[28/30] fbdev/core: Move file-I/O code into separate file

Commit Message

Thomas Zimmermann June 5, 2023, 2:48 p.m. UTC

Move fbdev's file-I/O code into a separate file and contain it in
init and cleanup helpers. No functional changes.

Signed-off-by: Thomas Zimmermann <[e-mail]>
---
 drivers/video/fbdev/core/Makefile      |   1 +
 drivers/video/fbdev/core/fb_devfs.c    | 484 +++++++++++++++++++++++++
 drivers/video/fbdev/core/fb_internal.h |   6 +
 drivers/video/fbdev/core/fbmem.c       | 478 +-----------------------
 4 files changed, 497 insertions(+), 472 deletions(-)
 create mode 100644 drivers/video/fbdev/core/fb_devfs.c

Comments

kernel test robot June 5, 2023, 9:35 p.m. UTC | #1

Hi Thomas,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20230605]
[cannot apply to drm-misc/drm-misc-next lee-backlight/for-backlight-next staging/staging-testing staging/staging-next staging/staging-linus linus/master lee-backlight/for-backlight-fixes v6.4-rc5 v6.4-rc4 v6.4-rc3 v6.4-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Thomas-Zimmermann/backlight-bd6107-Compare-against-struct-fb_info-device/20230605-225002
base:   next-20230605
patch link:    https://lore.kernel.org/r/20230605144812.15241-29-tzimmermann%40suse.de
patch subject: [PATCH 28/30] fbdev/core: Move file-I/O code into separate file
config: sparc-allyesconfig (https://download.01.org/0day-ci/archive/20230606/[e-mail]/config)
compiler: sparc64-linux-gcc (GCC) 12.3.0
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/34fb1357f6464f1173e12cd241310efa5577dd79
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Thomas-Zimmermann/backlight-bd6107-Compare-against-struct-fb_info-device/20230605-225002
        git checkout 34fb1357f6464f1173e12cd241310efa5577dd79
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=sparc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=sparc SHELL=/bin/bash drivers/video/fbdev/core/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[e-mail]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/

All warnings (new ones prefixed by >>):

   drivers/video/fbdev/core/fb_devfs.c:174:9: error: unknown type name 'compat_caddr_t'
     174 |         compat_caddr_t          smem_start;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:183:9: error: unknown type name 'compat_caddr_t'
     183 |         compat_caddr_t          mmio_start;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:192:9: error: unknown type name 'compat_caddr_t'
     192 |         compat_caddr_t  red;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:193:9: error: unknown type name 'compat_caddr_t'
     193 |         compat_caddr_t  green;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:194:9: error: unknown type name 'compat_caddr_t'
     194 |         compat_caddr_t  blue;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:195:9: error: unknown type name 'compat_caddr_t'
     195 |         compat_caddr_t  transp;
         |         ^~~~~~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c: In function 'fb_getput_cmap':
   drivers/video/fbdev/core/fb_devfs.c:205:37: error: implicit declaration of function 'compat_ptr' [-Werror=implicit-function-declaration]
     205 |         if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
         |                                     ^~~~~~~~~~
>> drivers/video/fbdev/core/fb_devfs.c:205:37: warning: passing argument 2 of 'copy_from_user' makes pointer from integer without a cast [-Wint-conversion]
     205 |         if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
         |                                     ^~~~~~~~~~~~~~~
         |                                     |
         |                                     int
   In file included from include/linux/sched/task.h:11,
                    from include/linux/sched/signal.h:9,
                    from include/linux/rcuwait.h:6,
                    from include/linux/percpu-rwsem.h:7,
                    from include/linux/fs.h:33,
                    from include/linux/huge_mm.h:8,
                    from include/linux/mm.h:989,
                    from include/linux/kallsyms.h:13,
                    from include/linux/ftrace.h:13,
                    from include/linux/kprobes.h:28,
                    from include/linux/kgdb.h:19,
                    from include/linux/fb.h:6,
                    from drivers/video/fbdev/core/fb_devfs.c:4:
   include/linux/uaccess.h:180:45: note: expected 'const void *' but argument is of type 'int'
     180 | copy_from_user(void *to, const void __user *from, unsigned long n)
         |                          ~~~~~~~~~~~~~~~~~~~^~~~
>> drivers/video/fbdev/core/fb_devfs.c:211:27: warning: initialization of '__u16 *' {aka 'short unsigned int *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
     211 |                 .red    = compat_ptr(cmap32.red),
         |                           ^~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:211:27: note: (near initialization for '(anonymous).red')
   drivers/video/fbdev/core/fb_devfs.c:212:27: warning: initialization of '__u16 *' {aka 'short unsigned int *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
     212 |                 .green  = compat_ptr(cmap32.green),
         |                           ^~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:212:27: note: (near initialization for '(anonymous).green')
   drivers/video/fbdev/core/fb_devfs.c:213:27: warning: initialization of '__u16 *' {aka 'short unsigned int *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
     213 |                 .blue   = compat_ptr(cmap32.blue),
         |                           ^~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:213:27: note: (near initialization for '(anonymous).blue')
   drivers/video/fbdev/core/fb_devfs.c:214:27: warning: initialization of '__u16 *' {aka 'short unsigned int *'} from 'int' makes pointer from integer without a cast [-Wint-conversion]
     214 |                 .transp = compat_ptr(cmap32.transp),
         |                           ^~~~~~~~~~
   drivers/video/fbdev/core/fb_devfs.c:214:27: note: (near initialization for '(anonymous).transp')
   drivers/video/fbdev/core/fb_devfs.c: In function 'fb_get_fscreeninfo':
>> drivers/video/fbdev/core/fb_devfs.c:270:45: warning: passing argument 2 of 'do_fscreeninfo_to_user' makes pointer from integer without a cast [-Wint-conversion]
     270 |         return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
         |                                             ^~~~~~~~~~~~~~~
         |                                             |
         |                                             int
   drivers/video/fbdev/core/fb_devfs.c:228:70: note: expected 'struct fb_fix_screeninfo32 *' but argument is of type 'int'
     228 |                                   struct fb_fix_screeninfo32 __user *fix32)
         |                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
   cc1: some warnings being treated as errors


vim +/copy_from_user +205 drivers/video/fbdev/core/fb_devfs.c

   197	
   198	static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
   199				  unsigned long arg)
   200	{
   201		struct fb_cmap32 cmap32;
   202		struct fb_cmap cmap_from;
   203		struct fb_cmap_user cmap;
   204	
 > 205		if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
   206			return -EFAULT;
   207	
   208		cmap = (struct fb_cmap_user) {
   209			.start	= cmap32.start,
   210			.len	= cmap32.len,
 > 211			.red	= compat_ptr(cmap32.red),
   212			.green	= compat_ptr(cmap32.green),
   213			.blue	= compat_ptr(cmap32.blue),
   214			.transp	= compat_ptr(cmap32.transp),
   215		};
   216	
   217		if (cmd == FBIOPUTCMAP)
   218			return fb_set_user_cmap(&cmap, info);
   219	
   220		lock_fb_info(info);
   221		cmap_from = info->cmap;
   222		unlock_fb_info(info);
   223	
   224		return fb_cmap_to_user(&cmap_from, &cmap);
   225	}
   226	
   227	static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
   228					  struct fb_fix_screeninfo32 __user *fix32)
   229	{
   230		__u32 data;
   231		int err;
   232	
   233		err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
   234	
   235		data = (__u32) (unsigned long) fix->smem_start;
   236		err |= put_user(data, &fix32->smem_start);
   237	
   238		err |= put_user(fix->smem_len, &fix32->smem_len);
   239		err |= put_user(fix->type, &fix32->type);
   240		err |= put_user(fix->type_aux, &fix32->type_aux);
   241		err |= put_user(fix->visual, &fix32->visual);
   242		err |= put_user(fix->xpanstep, &fix32->xpanstep);
   243		err |= put_user(fix->ypanstep, &fix32->ypanstep);
   244		err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
   245		err |= put_user(fix->line_length, &fix32->line_length);
   246	
   247		data = (__u32) (unsigned long) fix->mmio_start;
   248		err |= put_user(data, &fix32->mmio_start);
   249	
   250		err |= put_user(fix->mmio_len, &fix32->mmio_len);
   251		err |= put_user(fix->accel, &fix32->accel);
   252		err |= copy_to_user(fix32->reserved, fix->reserved,
   253				    sizeof(fix->reserved));
   254	
   255		if (err)
   256			return -EFAULT;
   257		return 0;
   258	}
   259	
   260	static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
   261				      unsigned long arg)
   262	{
   263		struct fb_fix_screeninfo fix;
   264	
   265		lock_fb_info(info);
   266		fix = info->fix;
   267		if (info->flags & FBINFO_HIDE_SMEM_START)
   268			fix.smem_start = 0;
   269		unlock_fb_info(info);
 > 270		return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
   271	}
   272

Sam Ravnborg June 7, 2023, 8:48 p.m. UTC | #2

Hi Thomas.

On Mon, Jun 05, 2023 at 04:48:10PM +0200, Thomas Zimmermann wrote:
> Move fbdev's file-I/O code into a separate file and contain it in
> init and cleanup helpers. No functional changes.
> 
> Signed-off-by: Thomas Zimmermann <[e-mail]>
Consider moving the two helps as noted below.
With or without this move:
Reviewed-by: Sam Ravnborg <[e-mail]>

> ---
>  drivers/video/fbdev/core/Makefile      |   1 +
>  drivers/video/fbdev/core/fb_devfs.c    | 484 +++++++++++++++++++++++++
>  drivers/video/fbdev/core/fb_internal.h |   6 +
>  drivers/video/fbdev/core/fbmem.c       | 478 +-----------------------
>  4 files changed, 497 insertions(+), 472 deletions(-)
>  create mode 100644 drivers/video/fbdev/core/fb_devfs.c
> 
> diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile
> index 665320160f70..125d24f50c36 100644
> --- a/drivers/video/fbdev/core/Makefile
> +++ b/drivers/video/fbdev/core/Makefile
> @@ -2,6 +2,7 @@
>  obj-$(CONFIG_FB_NOTIFY)           += fb_notify.o
>  obj-$(CONFIG_FB)                  += fb.o
>  fb-y                              := fb_backlight.o \
> +                                     fb_devfs.o \
>                                       fb_info.o \
>                                       fb_procfs.o \
>                                       fbmem.o fbmon.o fbcmap.o fbsysfs.o \
> diff --git a/drivers/video/fbdev/core/fb_devfs.c b/drivers/video/fbdev/core/fb_devfs.c
> new file mode 100644
> index 000000000000..5ab16cb24524
> --- /dev/null
> +++ b/drivers/video/fbdev/core/fb_devfs.c
devfs gives me another understanding of what this file is used for.
fb_ioctl.c?

> @@ -0,0 +1,484 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/console.h>
> +#include <linux/fb.h>
> +#include <linux/fbcon.h>
> +#include <linux/major.h>
> +
> +#include "fb_internal.h"
> +
> +/*
> + * We hold a reference to the fb_info in file->private_data,
> + * but if the current registered fb has changed, we don't
> + * actually want to use it.
> + *
> + * So look up the fb_info using the inode minor number,
> + * and just verify it against the reference we have.
> + */
> +static struct fb_info *file_fb_info(struct file *file)
> +{
> +	struct inode *inode = file_inode(file);
> +	int fbidx = iminor(inode);
> +	struct fb_info *info = registered_fb[fbidx];
> +
> +	if (info != file->private_data)
> +		info = NULL;
> +	return info;
> +}
> +
> +static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> +{
> +	struct fb_info *info = file_fb_info(file);
> +
> +	if (!info)
> +		return -ENODEV;
> +
> +	if (info->state != FBINFO_STATE_RUNNING)
> +		return -EPERM;
> +
> +	if (info->fbops->fb_read)
> +		return info->fbops->fb_read(info, buf, count, ppos);
> +
> +	return fb_io_read(info, buf, count, ppos);
> +}
> +
> +static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
> +{
> +	struct fb_info *info = file_fb_info(file);
> +
> +	if (!info)
> +		return -ENODEV;
> +
> +	if (info->state != FBINFO_STATE_RUNNING)
> +		return -EPERM;
> +
> +	if (info->fbops->fb_write)
> +		return info->fbops->fb_write(info, buf, count, ppos);
> +
> +	return fb_io_write(info, buf, count, ppos);
> +}
> +
> +static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
> +			unsigned long arg)
> +{
> +	const struct fb_ops *fb;
> +	struct fb_var_screeninfo var;
> +	struct fb_fix_screeninfo fix;
> +	struct fb_cmap cmap_from;
> +	struct fb_cmap_user cmap;
> +	void __user *argp = (void __user *)arg;
> +	long ret = 0;
> +
> +	switch (cmd) {
> +	case FBIOGET_VSCREENINFO:
> +		lock_fb_info(info);
> +		var = info->var;
> +		unlock_fb_info(info);
> +
> +		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
> +		break;
> +	case FBIOPUT_VSCREENINFO:
> +		if (copy_from_user(&var, argp, sizeof(var)))
> +			return -EFAULT;
> +		/* only for kernel-internal use */
> +		var.activate &= ~FB_ACTIVATE_KD_TEXT;
> +		console_lock();
> +		lock_fb_info(info);
> +		ret = fbcon_modechange_possible(info, &var);
> +		if (!ret)
> +			ret = fb_set_var(info, &var);
> +		if (!ret)
> +			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
> +		unlock_fb_info(info);
> +		console_unlock();
> +		if (!ret && copy_to_user(argp, &var, sizeof(var)))
> +			ret = -EFAULT;
> +		break;
> +	case FBIOGET_FSCREENINFO:
> +		lock_fb_info(info);
> +		memcpy(&fix, &info->fix, sizeof(fix));
> +		if (info->flags & FBINFO_HIDE_SMEM_START)
> +			fix.smem_start = 0;
> +		unlock_fb_info(info);
> +
> +		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
> +		break;
> +	case FBIOPUTCMAP:
> +		if (copy_from_user(&cmap, argp, sizeof(cmap)))
> +			return -EFAULT;
> +		ret = fb_set_user_cmap(&cmap, info);
> +		break;
> +	case FBIOGETCMAP:
> +		if (copy_from_user(&cmap, argp, sizeof(cmap)))
> +			return -EFAULT;
> +		lock_fb_info(info);
> +		cmap_from = info->cmap;
> +		unlock_fb_info(info);
> +		ret = fb_cmap_to_user(&cmap_from, &cmap);
> +		break;
> +	case FBIOPAN_DISPLAY:
> +		if (copy_from_user(&var, argp, sizeof(var)))
> +			return -EFAULT;
> +		console_lock();
> +		lock_fb_info(info);
> +		ret = fb_pan_display(info, &var);
> +		unlock_fb_info(info);
> +		console_unlock();
> +		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
> +			return -EFAULT;
> +		break;
> +	case FBIO_CURSOR:
> +		ret = -EINVAL;
> +		break;
> +	case FBIOGET_CON2FBMAP:
> +		ret = fbcon_get_con2fb_map_ioctl(argp);
> +		break;
> +	case FBIOPUT_CON2FBMAP:
> +		ret = fbcon_set_con2fb_map_ioctl(argp);
> +		break;
> +	case FBIOBLANK:
> +		if (arg > FB_BLANK_POWERDOWN)
> +			return -EINVAL;
> +		console_lock();
> +		lock_fb_info(info);
> +		ret = fb_blank(info, arg);
> +		/* might again call into fb_blank */
> +		fbcon_fb_blanked(info, arg);
> +		unlock_fb_info(info);
> +		console_unlock();
> +		break;
> +	default:
> +		lock_fb_info(info);
> +		fb = info->fbops;
> +		if (fb->fb_ioctl)
> +			ret = fb->fb_ioctl(info, cmd, arg);
> +		else
> +			ret = -ENOTTY;
> +		unlock_fb_info(info);
> +	}
> +	return ret;
> +}
> +
> +static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> +	struct fb_info *info = file_fb_info(file);
> +
> +	if (!info)
> +		return -ENODEV;
> +	return do_fb_ioctl(info, cmd, arg);
> +}
> +
> +#ifdef CONFIG_COMPAT
> +struct fb_fix_screeninfo32 {
> +	char			id[16];
> +	compat_caddr_t		smem_start;
> +	u32			smem_len;
> +	u32			type;
> +	u32			type_aux;
> +	u32			visual;
> +	u16			xpanstep;
> +	u16			ypanstep;
> +	u16			ywrapstep;
> +	u32			line_length;
> +	compat_caddr_t		mmio_start;
> +	u32			mmio_len;
> +	u32			accel;
> +	u16			reserved[3];
> +};
> +
> +struct fb_cmap32 {
> +	u32			start;
> +	u32			len;
> +	compat_caddr_t	red;
> +	compat_caddr_t	green;
> +	compat_caddr_t	blue;
> +	compat_caddr_t	transp;
> +};
> +
> +static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
> +			  unsigned long arg)
> +{
> +	struct fb_cmap32 cmap32;
> +	struct fb_cmap cmap_from;
> +	struct fb_cmap_user cmap;
> +
> +	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
> +		return -EFAULT;
> +
> +	cmap = (struct fb_cmap_user) {
> +		.start	= cmap32.start,
> +		.len	= cmap32.len,
> +		.red	= compat_ptr(cmap32.red),
> +		.green	= compat_ptr(cmap32.green),
> +		.blue	= compat_ptr(cmap32.blue),
> +		.transp	= compat_ptr(cmap32.transp),
> +	};
> +
> +	if (cmd == FBIOPUTCMAP)
> +		return fb_set_user_cmap(&cmap, info);
> +
> +	lock_fb_info(info);
> +	cmap_from = info->cmap;
> +	unlock_fb_info(info);
> +
> +	return fb_cmap_to_user(&cmap_from, &cmap);
> +}
> +
> +static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
> +				  struct fb_fix_screeninfo32 __user *fix32)
> +{
> +	__u32 data;
> +	int err;
> +
> +	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
> +
> +	data = (__u32) (unsigned long) fix->smem_start;
> +	err |= put_user(data, &fix32->smem_start);
> +
> +	err |= put_user(fix->smem_len, &fix32->smem_len);
> +	err |= put_user(fix->type, &fix32->type);
> +	err |= put_user(fix->type_aux, &fix32->type_aux);
> +	err |= put_user(fix->visual, &fix32->visual);
> +	err |= put_user(fix->xpanstep, &fix32->xpanstep);
> +	err |= put_user(fix->ypanstep, &fix32->ypanstep);
> +	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
> +	err |= put_user(fix->line_length, &fix32->line_length);
> +
> +	data = (__u32) (unsigned long) fix->mmio_start;
> +	err |= put_user(data, &fix32->mmio_start);
> +
> +	err |= put_user(fix->mmio_len, &fix32->mmio_len);
> +	err |= put_user(fix->accel, &fix32->accel);
> +	err |= copy_to_user(fix32->reserved, fix->reserved,
> +			    sizeof(fix->reserved));
> +
> +	if (err)
> +		return -EFAULT;
> +	return 0;
> +}
> +
> +static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
> +			      unsigned long arg)
> +{
> +	struct fb_fix_screeninfo fix;
> +
> +	lock_fb_info(info);
> +	fix = info->fix;
> +	if (info->flags & FBINFO_HIDE_SMEM_START)
> +		fix.smem_start = 0;
> +	unlock_fb_info(info);
> +	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
> +}
> +
> +static long fb_compat_ioctl(struct file *file, unsigned int cmd,
> +			    unsigned long arg)
> +{
> +	struct fb_info *info = file_fb_info(file);
> +	const struct fb_ops *fb;
> +	long ret = -ENOIOCTLCMD;
> +
> +	if (!info)
> +		return -ENODEV;
> +	fb = info->fbops;
> +	switch (cmd) {
> +	case FBIOGET_VSCREENINFO:
> +	case FBIOPUT_VSCREENINFO:
> +	case FBIOPAN_DISPLAY:
> +	case FBIOGET_CON2FBMAP:
> +	case FBIOPUT_CON2FBMAP:
> +		arg = (unsigned long) compat_ptr(arg);
> +		fallthrough;
> +	case FBIOBLANK:
> +		ret = do_fb_ioctl(info, cmd, arg);
> +		break;
> +
> +	case FBIOGET_FSCREENINFO:
> +		ret = fb_get_fscreeninfo(info, cmd, arg);
> +		break;
> +
> +	case FBIOGETCMAP:
> +	case FBIOPUTCMAP:
> +		ret = fb_getput_cmap(info, cmd, arg);
> +		break;
> +
> +	default:
> +		if (fb->fb_compat_ioctl)
> +			ret = fb->fb_compat_ioctl(info, cmd, arg);
> +		break;
> +	}
> +	return ret;
> +}
> +#endif
> +
> +static int fb_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> +	struct fb_info *info = file_fb_info(file);
> +	unsigned long mmio_pgoff;
> +	unsigned long start;
> +	u32 len;
> +
> +	if (!info)
> +		return -ENODEV;
> +	mutex_lock(&info->mm_lock);
> +
> +	if (info->fbops->fb_mmap) {
> +		int res;
> +
> +		/*
> +		 * The framebuffer needs to be accessed decrypted, be sure
> +		 * SME protection is removed ahead of the call
> +		 */
> +		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
> +		res = info->fbops->fb_mmap(info, vma);
> +		mutex_unlock(&info->mm_lock);
> +		return res;
> +#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
> +	} else if (info->fbdefio) {
> +		/*
> +		 * FB deferred I/O wants you to handle mmap in your drivers. At a
> +		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
> +		 */
> +		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
> +		mutex_unlock(&info->mm_lock);
> +		return -ENODEV;
> +#endif
> +	}
> +
> +	/*
> +	 * Ugh. This can be either the frame buffer mapping, or
> +	 * if pgoff points past it, the mmio mapping.
> +	 */
> +	start = info->fix.smem_start;
> +	len = info->fix.smem_len;
> +	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
> +	if (vma->vm_pgoff >= mmio_pgoff) {
> +		if (info->var.accel_flags) {
> +			mutex_unlock(&info->mm_lock);
> +			return -EINVAL;
> +		}
> +
> +		vma->vm_pgoff -= mmio_pgoff;
> +		start = info->fix.mmio_start;
> +		len = info->fix.mmio_len;
> +	}
> +	mutex_unlock(&info->mm_lock);
> +
> +	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> +	fb_pgprotect(file, vma, start);
> +
> +	return vm_iomap_memory(vma, start, len);
> +}
> +
> +static int fb_open(struct inode *inode, struct file *file)
> +__acquires(&info->lock)
> +__releases(&info->lock)
> +{
> +	int fbidx = iminor(inode);
> +	struct fb_info *info;
> +	int res = 0;
> +
> +	info = get_fb_info(fbidx);
> +	if (!info) {
> +		request_module("fb%d", fbidx);
> +		info = get_fb_info(fbidx);
> +		if (!info)
> +			return -ENODEV;
> +	}
> +	if (IS_ERR(info))
> +		return PTR_ERR(info);
> +
> +	lock_fb_info(info);
> +	if (!try_module_get(info->fbops->owner)) {
> +		res = -ENODEV;
> +		goto out;
> +	}
> +	file->private_data = info;
> +	if (info->fbops->fb_open) {
> +		res = info->fbops->fb_open(info, 1);
> +		if (res)
> +			module_put(info->fbops->owner);
> +	}
> +#ifdef CONFIG_FB_DEFERRED_IO
> +	if (info->fbdefio)
> +		fb_deferred_io_open(info, inode, file);
> +#endif
> +out:
> +	unlock_fb_info(info);
> +	if (res)
> +		put_fb_info(info);
> +	return res;
> +}
> +
> +static int fb_release(struct inode *inode, struct file *file)
> +__acquires(&info->lock)
> +__releases(&info->lock)
> +{
> +	struct fb_info * const info = file->private_data;
> +
> +	lock_fb_info(info);
> +#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
> +	if (info->fbdefio)
> +		fb_deferred_io_release(info);
> +#endif
> +	if (info->fbops->fb_release)
> +		info->fbops->fb_release(info, 1);
> +	module_put(info->fbops->owner);
> +	unlock_fb_info(info);
> +	put_fb_info(info);
> +	return 0;
> +}
> +
> +#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
> +static unsigned long get_fb_unmapped_area(struct file *filp,
> +				   unsigned long addr, unsigned long len,
> +				   unsigned long pgoff, unsigned long flags)
> +{
> +	struct fb_info * const info = filp->private_data;
> +	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
> +
> +	if (pgoff > fb_size || len > fb_size - pgoff)
> +		return -EINVAL;
> +
> +	return (unsigned long)info->screen_base + pgoff;
> +}
> +#endif
> +
> +static const struct file_operations fb_fops = {
> +	.owner = THIS_MODULE,
> +	.read = fb_read,
> +	.write = fb_write,
> +	.unlocked_ioctl = fb_ioctl,
> +#ifdef CONFIG_COMPAT
> +	.compat_ioctl = fb_compat_ioctl,
> +#endif
> +	.mmap = fb_mmap,
> +	.open = fb_open,
> +	.release = fb_release,
> +#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
> +	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
> +	 !defined(CONFIG_MMU))
> +	.get_unmapped_area = get_fb_unmapped_area,
> +#endif
> +#ifdef CONFIG_FB_DEFERRED_IO
> +	.fsync = fb_deferred_io_fsync,
> +#endif
> +	.llseek = default_llseek,
> +};
> +
> +int fb_register_chrdev(void)
> +{
> +	int ret;
> +
> +	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
> +	if (ret) {
> +		pr_err("Unable to get major %d for fb devs\n", FB_MAJOR);
> +		return ret;
> +	}
> +
> +	return ret;
> +}
> +
> +void fb_unregister_chrdev(void)
> +{
> +	unregister_chrdev(FB_MAJOR, "fb");
> +}
> diff --git a/drivers/video/fbdev/core/fb_internal.h b/drivers/video/fbdev/core/fb_internal.h
> index 51f7c9f04e45..abe06c9da36e 100644
> --- a/drivers/video/fbdev/core/fb_internal.h
> +++ b/drivers/video/fbdev/core/fb_internal.h
> @@ -6,10 +6,16 @@
>  #include <linux/fb.h>
>  #include <linux/mutex.h>
>  
> +/* fb_devfs.c */
> +int fb_register_chrdev(void);
> +void fb_unregister_chrdev(void);
> +
>  /* fbmem.c */
>  extern struct mutex registration_lock;
>  extern struct fb_info *registered_fb[FB_MAX];
>  extern int num_registered_fb;
> +struct fb_info *get_fb_info(unsigned int idx);
> +void put_fb_info(struct fb_info *fb_info);
The only users of get_fb_info() and put_fb_info() are now in fb_devfs.
So consider moving these two helpers too.

>  
>  /* fb_procfs.c */
>  int fb_init_procfs(void);
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index de1e45240161..2d26ac46337b 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -17,7 +17,6 @@
>  #include <linux/types.h>
>  #include <linux/errno.h>
>  #include <linux/kernel.h>
> -#include <linux/major.h>
>  #include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/mman.h>
> @@ -54,7 +53,7 @@ bool fb_center_logo __read_mostly;
>  
>  int fb_logo_count __read_mostly = -1;
>  
> -static struct fb_info *get_fb_info(unsigned int idx)
> +struct fb_info *get_fb_info(unsigned int idx)
>  {
>  	struct fb_info *fb_info;
>  
> @@ -70,7 +69,7 @@ static struct fb_info *get_fb_info(unsigned int idx)
>  	return fb_info;
>  }
>  
> -static void put_fb_info(struct fb_info *fb_info)
> +void put_fb_info(struct fb_info *fb_info)
>  {
>  	if (!refcount_dec_and_test(&fb_info->count))
>  		return;
> @@ -699,59 +698,6 @@ int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
>  EXPORT_SYMBOL(fb_prepare_logo);
>  EXPORT_SYMBOL(fb_show_logo);

Reminds me - consider moving logo stuff to a fb_logo file.
This would reduce fbmem with a lot of lines, and it is separate.
But it is outside the goal of this patchset.

>  
> -/*
> - * We hold a reference to the fb_info in file->private_data,
> - * but if the current registered fb has changed, we don't
> - * actually want to use it.
> - *
> - * So look up the fb_info using the inode minor number,
> - * and just verify it against the reference we have.
> - */
> -static struct fb_info *file_fb_info(struct file *file)
> -{
> -	struct inode *inode = file_inode(file);
> -	int fbidx = iminor(inode);
> -	struct fb_info *info = registered_fb[fbidx];
> -
> -	if (info != file->private_data)
> -		info = NULL;
> -	return info;
> -}
> -
> -static ssize_t
> -fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
> -{
> -	struct fb_info *info = file_fb_info(file);
> -
> -	if (!info)
> -		return -ENODEV;
> -
> -	if (info->state != FBINFO_STATE_RUNNING)
> -		return -EPERM;
> -
> -	if (info->fbops->fb_read)
> -		return info->fbops->fb_read(info, buf, count, ppos);
> -
> -	return fb_io_read(info, buf, count, ppos);
> -}
> -
> -static ssize_t
> -fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
> -{
> -	struct fb_info *info = file_fb_info(file);
> -
> -	if (!info)
> -		return -ENODEV;
> -
> -	if (info->state != FBINFO_STATE_RUNNING)
> -		return -EPERM;
> -
> -	if (info->fbops->fb_write)
> -		return info->fbops->fb_write(info, buf, count, ppos);
> -
> -	return fb_io_write(info, buf, count, ppos);
> -}
> -
>  int
>  fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
>  {
> @@ -951,416 +897,6 @@ fb_blank(struct fb_info *info, int blank)
>  }
>  EXPORT_SYMBOL(fb_blank);
>  
> -static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
> -			unsigned long arg)
> -{
> -	const struct fb_ops *fb;
> -	struct fb_var_screeninfo var;
> -	struct fb_fix_screeninfo fix;
> -	struct fb_cmap cmap_from;
> -	struct fb_cmap_user cmap;
> -	void __user *argp = (void __user *)arg;
> -	long ret = 0;
> -
> -	switch (cmd) {
> -	case FBIOGET_VSCREENINFO:
> -		lock_fb_info(info);
> -		var = info->var;
> -		unlock_fb_info(info);
> -
> -		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
> -		break;
> -	case FBIOPUT_VSCREENINFO:
> -		if (copy_from_user(&var, argp, sizeof(var)))
> -			return -EFAULT;
> -		/* only for kernel-internal use */
> -		var.activate &= ~FB_ACTIVATE_KD_TEXT;
> -		console_lock();
> -		lock_fb_info(info);
> -		ret = fbcon_modechange_possible(info, &var);
> -		if (!ret)
> -			ret = fb_set_var(info, &var);
> -		if (!ret)
> -			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
> -		unlock_fb_info(info);
> -		console_unlock();
> -		if (!ret && copy_to_user(argp, &var, sizeof(var)))
> -			ret = -EFAULT;
> -		break;
> -	case FBIOGET_FSCREENINFO:
> -		lock_fb_info(info);
> -		memcpy(&fix, &info->fix, sizeof(fix));
> -		if (info->flags & FBINFO_HIDE_SMEM_START)
> -			fix.smem_start = 0;
> -		unlock_fb_info(info);
> -
> -		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
> -		break;
> -	case FBIOPUTCMAP:
> -		if (copy_from_user(&cmap, argp, sizeof(cmap)))
> -			return -EFAULT;
> -		ret = fb_set_user_cmap(&cmap, info);
> -		break;
> -	case FBIOGETCMAP:
> -		if (copy_from_user(&cmap, argp, sizeof(cmap)))
> -			return -EFAULT;
> -		lock_fb_info(info);
> -		cmap_from = info->cmap;
> -		unlock_fb_info(info);
> -		ret = fb_cmap_to_user(&cmap_from, &cmap);
> -		break;
> -	case FBIOPAN_DISPLAY:
> -		if (copy_from_user(&var, argp, sizeof(var)))
> -			return -EFAULT;
> -		console_lock();
> -		lock_fb_info(info);
> -		ret = fb_pan_display(info, &var);
> -		unlock_fb_info(info);
> -		console_unlock();
> -		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
> -			return -EFAULT;
> -		break;
> -	case FBIO_CURSOR:
> -		ret = -EINVAL;
> -		break;
> -	case FBIOGET_CON2FBMAP:
> -		ret = fbcon_get_con2fb_map_ioctl(argp);
> -		break;
> -	case FBIOPUT_CON2FBMAP:
> -		ret = fbcon_set_con2fb_map_ioctl(argp);
> -		break;
> -	case FBIOBLANK:
> -		if (arg > FB_BLANK_POWERDOWN)
> -			return -EINVAL;
> -		console_lock();
> -		lock_fb_info(info);
> -		ret = fb_blank(info, arg);
> -		/* might again call into fb_blank */
> -		fbcon_fb_blanked(info, arg);
> -		unlock_fb_info(info);
> -		console_unlock();
> -		break;
> -	default:
> -		lock_fb_info(info);
> -		fb = info->fbops;
> -		if (fb->fb_ioctl)
> -			ret = fb->fb_ioctl(info, cmd, arg);
> -		else
> -			ret = -ENOTTY;
> -		unlock_fb_info(info);
> -	}
> -	return ret;
> -}
> -
> -static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> -{
> -	struct fb_info *info = file_fb_info(file);
> -
> -	if (!info)
> -		return -ENODEV;
> -	return do_fb_ioctl(info, cmd, arg);
> -}
> -
> -#ifdef CONFIG_COMPAT
> -struct fb_fix_screeninfo32 {
> -	char			id[16];
> -	compat_caddr_t		smem_start;
> -	u32			smem_len;
> -	u32			type;
> -	u32			type_aux;
> -	u32			visual;
> -	u16			xpanstep;
> -	u16			ypanstep;
> -	u16			ywrapstep;
> -	u32			line_length;
> -	compat_caddr_t		mmio_start;
> -	u32			mmio_len;
> -	u32			accel;
> -	u16			reserved[3];
> -};
> -
> -struct fb_cmap32 {
> -	u32			start;
> -	u32			len;
> -	compat_caddr_t	red;
> -	compat_caddr_t	green;
> -	compat_caddr_t	blue;
> -	compat_caddr_t	transp;
> -};
> -
> -static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
> -			  unsigned long arg)
> -{
> -	struct fb_cmap32 cmap32;
> -	struct fb_cmap cmap_from;
> -	struct fb_cmap_user cmap;
> -
> -	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
> -		return -EFAULT;
> -
> -	cmap = (struct fb_cmap_user) {
> -		.start	= cmap32.start,
> -		.len	= cmap32.len,
> -		.red	= compat_ptr(cmap32.red),
> -		.green	= compat_ptr(cmap32.green),
> -		.blue	= compat_ptr(cmap32.blue),
> -		.transp	= compat_ptr(cmap32.transp),
> -	};
> -
> -	if (cmd == FBIOPUTCMAP)
> -		return fb_set_user_cmap(&cmap, info);
> -
> -	lock_fb_info(info);
> -	cmap_from = info->cmap;
> -	unlock_fb_info(info);
> -
> -	return fb_cmap_to_user(&cmap_from, &cmap);
> -}
> -
> -static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
> -				  struct fb_fix_screeninfo32 __user *fix32)
> -{
> -	__u32 data;
> -	int err;
> -
> -	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
> -
> -	data = (__u32) (unsigned long) fix->smem_start;
> -	err |= put_user(data, &fix32->smem_start);
> -
> -	err |= put_user(fix->smem_len, &fix32->smem_len);
> -	err |= put_user(fix->type, &fix32->type);
> -	err |= put_user(fix->type_aux, &fix32->type_aux);
> -	err |= put_user(fix->visual, &fix32->visual);
> -	err |= put_user(fix->xpanstep, &fix32->xpanstep);
> -	err |= put_user(fix->ypanstep, &fix32->ypanstep);
> -	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
> -	err |= put_user(fix->line_length, &fix32->line_length);
> -
> -	data = (__u32) (unsigned long) fix->mmio_start;
> -	err |= put_user(data, &fix32->mmio_start);
> -
> -	err |= put_user(fix->mmio_len, &fix32->mmio_len);
> -	err |= put_user(fix->accel, &fix32->accel);
> -	err |= copy_to_user(fix32->reserved, fix->reserved,
> -			    sizeof(fix->reserved));
> -
> -	if (err)
> -		return -EFAULT;
> -	return 0;
> -}
> -
> -static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
> -			      unsigned long arg)
> -{
> -	struct fb_fix_screeninfo fix;
> -
> -	lock_fb_info(info);
> -	fix = info->fix;
> -	if (info->flags & FBINFO_HIDE_SMEM_START)
> -		fix.smem_start = 0;
> -	unlock_fb_info(info);
> -	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
> -}
> -
> -static long fb_compat_ioctl(struct file *file, unsigned int cmd,
> -			    unsigned long arg)
> -{
> -	struct fb_info *info = file_fb_info(file);
> -	const struct fb_ops *fb;
> -	long ret = -ENOIOCTLCMD;
> -
> -	if (!info)
> -		return -ENODEV;
> -	fb = info->fbops;
> -	switch(cmd) {
> -	case FBIOGET_VSCREENINFO:
> -	case FBIOPUT_VSCREENINFO:
> -	case FBIOPAN_DISPLAY:
> -	case FBIOGET_CON2FBMAP:
> -	case FBIOPUT_CON2FBMAP:
> -		arg = (unsigned long) compat_ptr(arg);
> -		fallthrough;
> -	case FBIOBLANK:
> -		ret = do_fb_ioctl(info, cmd, arg);
> -		break;
> -
> -	case FBIOGET_FSCREENINFO:
> -		ret = fb_get_fscreeninfo(info, cmd, arg);
> -		break;
> -
> -	case FBIOGETCMAP:
> -	case FBIOPUTCMAP:
> -		ret = fb_getput_cmap(info, cmd, arg);
> -		break;
> -
> -	default:
> -		if (fb->fb_compat_ioctl)
> -			ret = fb->fb_compat_ioctl(info, cmd, arg);
> -		break;
> -	}
> -	return ret;
> -}
> -#endif
> -
> -static int
> -fb_mmap(struct file *file, struct vm_area_struct * vma)
> -{
> -	struct fb_info *info = file_fb_info(file);
> -	unsigned long mmio_pgoff;
> -	unsigned long start;
> -	u32 len;
> -
> -	if (!info)
> -		return -ENODEV;
> -	mutex_lock(&info->mm_lock);
> -
> -	if (info->fbops->fb_mmap) {
> -		int res;
> -
> -		/*
> -		 * The framebuffer needs to be accessed decrypted, be sure
> -		 * SME protection is removed ahead of the call
> -		 */
> -		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
> -		res = info->fbops->fb_mmap(info, vma);
> -		mutex_unlock(&info->mm_lock);
> -		return res;
> -#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
> -	} else if (info->fbdefio) {
> -		/*
> -		 * FB deferred I/O wants you to handle mmap in your drivers. At a
> -		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
> -		 */
> -		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
> -		mutex_unlock(&info->mm_lock);
> -		return -ENODEV;
> -#endif
> -	}
> -
> -	/*
> -	 * Ugh. This can be either the frame buffer mapping, or
> -	 * if pgoff points past it, the mmio mapping.
> -	 */
> -	start = info->fix.smem_start;
> -	len = info->fix.smem_len;
> -	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
> -	if (vma->vm_pgoff >= mmio_pgoff) {
> -		if (info->var.accel_flags) {
> -			mutex_unlock(&info->mm_lock);
> -			return -EINVAL;
> -		}
> -
> -		vma->vm_pgoff -= mmio_pgoff;
> -		start = info->fix.mmio_start;
> -		len = info->fix.mmio_len;
> -	}
> -	mutex_unlock(&info->mm_lock);
> -
> -	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> -	fb_pgprotect(file, vma, start);
> -
> -	return vm_iomap_memory(vma, start, len);
> -}
> -
> -static int
> -fb_open(struct inode *inode, struct file *file)
> -__acquires(&info->lock)
> -__releases(&info->lock)
> -{
> -	int fbidx = iminor(inode);
> -	struct fb_info *info;
> -	int res = 0;
> -
> -	info = get_fb_info(fbidx);
> -	if (!info) {
> -		request_module("fb%d", fbidx);
> -		info = get_fb_info(fbidx);
> -		if (!info)
> -			return -ENODEV;
> -	}
> -	if (IS_ERR(info))
> -		return PTR_ERR(info);
> -
> -	lock_fb_info(info);
> -	if (!try_module_get(info->fbops->owner)) {
> -		res = -ENODEV;
> -		goto out;
> -	}
> -	file->private_data = info;
> -	if (info->fbops->fb_open) {
> -		res = info->fbops->fb_open(info,1);
> -		if (res)
> -			module_put(info->fbops->owner);
> -	}
> -#ifdef CONFIG_FB_DEFERRED_IO
> -	if (info->fbdefio)
> -		fb_deferred_io_open(info, inode, file);
> -#endif
> -out:
> -	unlock_fb_info(info);
> -	if (res)
> -		put_fb_info(info);
> -	return res;
> -}
> -
> -static int
> -fb_release(struct inode *inode, struct file *file)
> -__acquires(&info->lock)
> -__releases(&info->lock)
> -{
> -	struct fb_info * const info = file->private_data;
> -
> -	lock_fb_info(info);
> -#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
> -	if (info->fbdefio)
> -		fb_deferred_io_release(info);
> -#endif
> -	if (info->fbops->fb_release)
> -		info->fbops->fb_release(info,1);
> -	module_put(info->fbops->owner);
> -	unlock_fb_info(info);
> -	put_fb_info(info);
> -	return 0;
> -}
> -
> -#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
> -static unsigned long get_fb_unmapped_area(struct file *filp,
> -				   unsigned long addr, unsigned long len,
> -				   unsigned long pgoff, unsigned long flags)
> -{
> -	struct fb_info * const info = filp->private_data;
> -	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
> -
> -	if (pgoff > fb_size || len > fb_size - pgoff)
> -		return -EINVAL;
> -
> -	return (unsigned long)info->screen_base + pgoff;
> -}
> -#endif
> -
> -static const struct file_operations fb_fops = {
> -	.owner =	THIS_MODULE,
> -	.read =		fb_read,
> -	.write =	fb_write,
> -	.unlocked_ioctl = fb_ioctl,
> -#ifdef CONFIG_COMPAT
> -	.compat_ioctl = fb_compat_ioctl,
> -#endif
> -	.mmap =		fb_mmap,
> -	.open =		fb_open,
> -	.release =	fb_release,
> -#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
> -	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
> -	 !defined(CONFIG_MMU))
> -	.get_unmapped_area = get_fb_unmapped_area,
> -#endif
> -#ifdef CONFIG_FB_DEFERRED_IO
> -	.fsync =	fb_deferred_io_fsync,
> -#endif
> -	.llseek =	default_llseek,
> -};
> -
>  struct class *fb_class;
>  EXPORT_SYMBOL(fb_class);
>  
> @@ -1588,11 +1124,9 @@ fbmem_init(void)
>  	if (ret)
>  		return ret;
>  
> -	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
> -	if (ret) {
> -		printk("unable to get major %d for fb devs\n", FB_MAJOR);
> +	ret = fb_register_chrdev();
> +	if (ret)
>  		goto err_chrdev;
> -	}
>  
>  	fb_class = class_create("graphics");
>  	if (IS_ERR(fb_class)) {
> @@ -1607,7 +1141,7 @@ fbmem_init(void)
>  	return 0;
>  
>  err_class:
> -	unregister_chrdev(FB_MAJOR, "fb");
> +	fb_unregister_chrdev();
>  err_chrdev:
>  	fb_cleanup_procfs();
>  	return ret;
> @@ -1622,7 +1156,7 @@ fbmem_exit(void)
>  
>  	fb_cleanup_procfs();
>  	class_destroy(fb_class);
> -	unregister_chrdev(FB_MAJOR, "fb");
> +	fb_unregister_chrdev();
>  }
>  
>  module_exit(fbmem_exit);
> -- 
> 2.40.1

Javier Martinez Canillas June 7, 2023, 10:28 p.m. UTC | #3

Thomas Zimmermann <[e-mail]> writes:

> Move fbdev's file-I/O code into a separate file and contain it in
> init and cleanup helpers. No functional changes.
>
> Signed-off-by: Thomas Zimmermann <[e-mail]>
> ---

[...]

> +
> +#include <linux/console.h>

#include <linux/compat.h> here, the robot complained about:

   drivers/video/fbdev/core/fb_devfs.c:183:9: error: unknown type name 'compat_caddr_t'

Thomas Zimmermann June 12, 2023, 10:35 a.m. UTC | #4

Hi

Am 07.06.23 um 22:48 schrieb Sam Ravnborg:
> Hi Thomas.
> 
> On Mon, Jun 05, 2023 at 04:48:10PM +0200, Thomas Zimmermann wrote:
>> Move fbdev's file-I/O code into a separate file and contain it in
>> init and cleanup helpers. No functional changes.
>>
>> Signed-off-by: Thomas Zimmermann <[e-mail]>
> Consider moving the two helps as noted below.
> With or without this move:
> Reviewed-by: Sam Ravnborg <[e-mail]>
> 
>> ---
>>   drivers/video/fbdev/core/Makefile      |   1 +
>>   drivers/video/fbdev/core/fb_devfs.c    | 484 +++++++++++++++++++++++++
>>   drivers/video/fbdev/core/fb_internal.h |   6 +
>>   drivers/video/fbdev/core/fbmem.c       | 478 +-----------------------
>>   4 files changed, 497 insertions(+), 472 deletions(-)
>>   create mode 100644 drivers/video/fbdev/core/fb_devfs.c
>>
>> diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile
>> index 665320160f70..125d24f50c36 100644
>> --- a/drivers/video/fbdev/core/Makefile
>> +++ b/drivers/video/fbdev/core/Makefile
>> @@ -2,6 +2,7 @@
>>   obj-$(CONFIG_FB_NOTIFY)           += fb_notify.o
>>   obj-$(CONFIG_FB)                  += fb.o
>>   fb-y                              := fb_backlight.o \
>> +                                     fb_devfs.o \
>>                                        fb_info.o \
>>                                        fb_procfs.o \
>>                                        fbmem.o fbmon.o fbcmap.o fbsysfs.o \
>> diff --git a/drivers/video/fbdev/core/fb_devfs.c b/drivers/video/fbdev/core/fb_devfs.c
>> new file mode 100644
>> index 000000000000..5ab16cb24524
>> --- /dev/null
>> +++ b/drivers/video/fbdev/core/fb_devfs.c
> devfs gives me another understanding of what this file is used for.
> fb_ioctl.c?

I think fb_chrdev.c would be appropriate.

Best regards
Thomas

> 
>> @@ -0,0 +1,484 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/console.h>
>> +#include <linux/fb.h>
>> +#include <linux/fbcon.h>
>> +#include <linux/major.h>
>> +
>> +#include "fb_internal.h"
>> +
>> +/*
>> + * We hold a reference to the fb_info in file->private_data,
>> + * but if the current registered fb has changed, we don't
>> + * actually want to use it.
>> + *
>> + * So look up the fb_info using the inode minor number,
>> + * and just verify it against the reference we have.
>> + */
>> +static struct fb_info *file_fb_info(struct file *file)
>> +{
>> +	struct inode *inode = file_inode(file);
>> +	int fbidx = iminor(inode);
>> +	struct fb_info *info = registered_fb[fbidx];
>> +
>> +	if (info != file->private_data)
>> +		info = NULL;
>> +	return info;
>> +}
>> +
>> +static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> +{
>> +	struct fb_info *info = file_fb_info(file);
>> +
>> +	if (!info)
>> +		return -ENODEV;
>> +
>> +	if (info->state != FBINFO_STATE_RUNNING)
>> +		return -EPERM;
>> +
>> +	if (info->fbops->fb_read)
>> +		return info->fbops->fb_read(info, buf, count, ppos);
>> +
>> +	return fb_io_read(info, buf, count, ppos);
>> +}
>> +
>> +static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
>> +{
>> +	struct fb_info *info = file_fb_info(file);
>> +
>> +	if (!info)
>> +		return -ENODEV;
>> +
>> +	if (info->state != FBINFO_STATE_RUNNING)
>> +		return -EPERM;
>> +
>> +	if (info->fbops->fb_write)
>> +		return info->fbops->fb_write(info, buf, count, ppos);
>> +
>> +	return fb_io_write(info, buf, count, ppos);
>> +}
>> +
>> +static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>> +			unsigned long arg)
>> +{
>> +	const struct fb_ops *fb;
>> +	struct fb_var_screeninfo var;
>> +	struct fb_fix_screeninfo fix;
>> +	struct fb_cmap cmap_from;
>> +	struct fb_cmap_user cmap;
>> +	void __user *argp = (void __user *)arg;
>> +	long ret = 0;
>> +
>> +	switch (cmd) {
>> +	case FBIOGET_VSCREENINFO:
>> +		lock_fb_info(info);
>> +		var = info->var;
>> +		unlock_fb_info(info);
>> +
>> +		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
>> +		break;
>> +	case FBIOPUT_VSCREENINFO:
>> +		if (copy_from_user(&var, argp, sizeof(var)))
>> +			return -EFAULT;
>> +		/* only for kernel-internal use */
>> +		var.activate &= ~FB_ACTIVATE_KD_TEXT;
>> +		console_lock();
>> +		lock_fb_info(info);
>> +		ret = fbcon_modechange_possible(info, &var);
>> +		if (!ret)
>> +			ret = fb_set_var(info, &var);
>> +		if (!ret)
>> +			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
>> +		unlock_fb_info(info);
>> +		console_unlock();
>> +		if (!ret && copy_to_user(argp, &var, sizeof(var)))
>> +			ret = -EFAULT;
>> +		break;
>> +	case FBIOGET_FSCREENINFO:
>> +		lock_fb_info(info);
>> +		memcpy(&fix, &info->fix, sizeof(fix));
>> +		if (info->flags & FBINFO_HIDE_SMEM_START)
>> +			fix.smem_start = 0;
>> +		unlock_fb_info(info);
>> +
>> +		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
>> +		break;
>> +	case FBIOPUTCMAP:
>> +		if (copy_from_user(&cmap, argp, sizeof(cmap)))
>> +			return -EFAULT;
>> +		ret = fb_set_user_cmap(&cmap, info);
>> +		break;
>> +	case FBIOGETCMAP:
>> +		if (copy_from_user(&cmap, argp, sizeof(cmap)))
>> +			return -EFAULT;
>> +		lock_fb_info(info);
>> +		cmap_from = info->cmap;
>> +		unlock_fb_info(info);
>> +		ret = fb_cmap_to_user(&cmap_from, &cmap);
>> +		break;
>> +	case FBIOPAN_DISPLAY:
>> +		if (copy_from_user(&var, argp, sizeof(var)))
>> +			return -EFAULT;
>> +		console_lock();
>> +		lock_fb_info(info);
>> +		ret = fb_pan_display(info, &var);
>> +		unlock_fb_info(info);
>> +		console_unlock();
>> +		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
>> +			return -EFAULT;
>> +		break;
>> +	case FBIO_CURSOR:
>> +		ret = -EINVAL;
>> +		break;
>> +	case FBIOGET_CON2FBMAP:
>> +		ret = fbcon_get_con2fb_map_ioctl(argp);
>> +		break;
>> +	case FBIOPUT_CON2FBMAP:
>> +		ret = fbcon_set_con2fb_map_ioctl(argp);
>> +		break;
>> +	case FBIOBLANK:
>> +		if (arg > FB_BLANK_POWERDOWN)
>> +			return -EINVAL;
>> +		console_lock();
>> +		lock_fb_info(info);
>> +		ret = fb_blank(info, arg);
>> +		/* might again call into fb_blank */
>> +		fbcon_fb_blanked(info, arg);
>> +		unlock_fb_info(info);
>> +		console_unlock();
>> +		break;
>> +	default:
>> +		lock_fb_info(info);
>> +		fb = info->fbops;
>> +		if (fb->fb_ioctl)
>> +			ret = fb->fb_ioctl(info, cmd, arg);
>> +		else
>> +			ret = -ENOTTY;
>> +		unlock_fb_info(info);
>> +	}
>> +	return ret;
>> +}
>> +
>> +static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>> +{
>> +	struct fb_info *info = file_fb_info(file);
>> +
>> +	if (!info)
>> +		return -ENODEV;
>> +	return do_fb_ioctl(info, cmd, arg);
>> +}
>> +
>> +#ifdef CONFIG_COMPAT
>> +struct fb_fix_screeninfo32 {
>> +	char			id[16];
>> +	compat_caddr_t		smem_start;
>> +	u32			smem_len;
>> +	u32			type;
>> +	u32			type_aux;
>> +	u32			visual;
>> +	u16			xpanstep;
>> +	u16			ypanstep;
>> +	u16			ywrapstep;
>> +	u32			line_length;
>> +	compat_caddr_t		mmio_start;
>> +	u32			mmio_len;
>> +	u32			accel;
>> +	u16			reserved[3];
>> +};
>> +
>> +struct fb_cmap32 {
>> +	u32			start;
>> +	u32			len;
>> +	compat_caddr_t	red;
>> +	compat_caddr_t	green;
>> +	compat_caddr_t	blue;
>> +	compat_caddr_t	transp;
>> +};
>> +
>> +static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
>> +			  unsigned long arg)
>> +{
>> +	struct fb_cmap32 cmap32;
>> +	struct fb_cmap cmap_from;
>> +	struct fb_cmap_user cmap;
>> +
>> +	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
>> +		return -EFAULT;
>> +
>> +	cmap = (struct fb_cmap_user) {
>> +		.start	= cmap32.start,
>> +		.len	= cmap32.len,
>> +		.red	= compat_ptr(cmap32.red),
>> +		.green	= compat_ptr(cmap32.green),
>> +		.blue	= compat_ptr(cmap32.blue),
>> +		.transp	= compat_ptr(cmap32.transp),
>> +	};
>> +
>> +	if (cmd == FBIOPUTCMAP)
>> +		return fb_set_user_cmap(&cmap, info);
>> +
>> +	lock_fb_info(info);
>> +	cmap_from = info->cmap;
>> +	unlock_fb_info(info);
>> +
>> +	return fb_cmap_to_user(&cmap_from, &cmap);
>> +}
>> +
>> +static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
>> +				  struct fb_fix_screeninfo32 __user *fix32)
>> +{
>> +	__u32 data;
>> +	int err;
>> +
>> +	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
>> +
>> +	data = (__u32) (unsigned long) fix->smem_start;
>> +	err |= put_user(data, &fix32->smem_start);
>> +
>> +	err |= put_user(fix->smem_len, &fix32->smem_len);
>> +	err |= put_user(fix->type, &fix32->type);
>> +	err |= put_user(fix->type_aux, &fix32->type_aux);
>> +	err |= put_user(fix->visual, &fix32->visual);
>> +	err |= put_user(fix->xpanstep, &fix32->xpanstep);
>> +	err |= put_user(fix->ypanstep, &fix32->ypanstep);
>> +	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
>> +	err |= put_user(fix->line_length, &fix32->line_length);
>> +
>> +	data = (__u32) (unsigned long) fix->mmio_start;
>> +	err |= put_user(data, &fix32->mmio_start);
>> +
>> +	err |= put_user(fix->mmio_len, &fix32->mmio_len);
>> +	err |= put_user(fix->accel, &fix32->accel);
>> +	err |= copy_to_user(fix32->reserved, fix->reserved,
>> +			    sizeof(fix->reserved));
>> +
>> +	if (err)
>> +		return -EFAULT;
>> +	return 0;
>> +}
>> +
>> +static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
>> +			      unsigned long arg)
>> +{
>> +	struct fb_fix_screeninfo fix;
>> +
>> +	lock_fb_info(info);
>> +	fix = info->fix;
>> +	if (info->flags & FBINFO_HIDE_SMEM_START)
>> +		fix.smem_start = 0;
>> +	unlock_fb_info(info);
>> +	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
>> +}
>> +
>> +static long fb_compat_ioctl(struct file *file, unsigned int cmd,
>> +			    unsigned long arg)
>> +{
>> +	struct fb_info *info = file_fb_info(file);
>> +	const struct fb_ops *fb;
>> +	long ret = -ENOIOCTLCMD;
>> +
>> +	if (!info)
>> +		return -ENODEV;
>> +	fb = info->fbops;
>> +	switch (cmd) {
>> +	case FBIOGET_VSCREENINFO:
>> +	case FBIOPUT_VSCREENINFO:
>> +	case FBIOPAN_DISPLAY:
>> +	case FBIOGET_CON2FBMAP:
>> +	case FBIOPUT_CON2FBMAP:
>> +		arg = (unsigned long) compat_ptr(arg);
>> +		fallthrough;
>> +	case FBIOBLANK:
>> +		ret = do_fb_ioctl(info, cmd, arg);
>> +		break;
>> +
>> +	case FBIOGET_FSCREENINFO:
>> +		ret = fb_get_fscreeninfo(info, cmd, arg);
>> +		break;
>> +
>> +	case FBIOGETCMAP:
>> +	case FBIOPUTCMAP:
>> +		ret = fb_getput_cmap(info, cmd, arg);
>> +		break;
>> +
>> +	default:
>> +		if (fb->fb_compat_ioctl)
>> +			ret = fb->fb_compat_ioctl(info, cmd, arg);
>> +		break;
>> +	}
>> +	return ret;
>> +}
>> +#endif
>> +
>> +static int fb_mmap(struct file *file, struct vm_area_struct *vma)
>> +{
>> +	struct fb_info *info = file_fb_info(file);
>> +	unsigned long mmio_pgoff;
>> +	unsigned long start;
>> +	u32 len;
>> +
>> +	if (!info)
>> +		return -ENODEV;
>> +	mutex_lock(&info->mm_lock);
>> +
>> +	if (info->fbops->fb_mmap) {
>> +		int res;
>> +
>> +		/*
>> +		 * The framebuffer needs to be accessed decrypted, be sure
>> +		 * SME protection is removed ahead of the call
>> +		 */
>> +		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
>> +		res = info->fbops->fb_mmap(info, vma);
>> +		mutex_unlock(&info->mm_lock);
>> +		return res;
>> +#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
>> +	} else if (info->fbdefio) {
>> +		/*
>> +		 * FB deferred I/O wants you to handle mmap in your drivers. At a
>> +		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
>> +		 */
>> +		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
>> +		mutex_unlock(&info->mm_lock);
>> +		return -ENODEV;
>> +#endif
>> +	}
>> +
>> +	/*
>> +	 * Ugh. This can be either the frame buffer mapping, or
>> +	 * if pgoff points past it, the mmio mapping.
>> +	 */
>> +	start = info->fix.smem_start;
>> +	len = info->fix.smem_len;
>> +	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
>> +	if (vma->vm_pgoff >= mmio_pgoff) {
>> +		if (info->var.accel_flags) {
>> +			mutex_unlock(&info->mm_lock);
>> +			return -EINVAL;
>> +		}
>> +
>> +		vma->vm_pgoff -= mmio_pgoff;
>> +		start = info->fix.mmio_start;
>> +		len = info->fix.mmio_len;
>> +	}
>> +	mutex_unlock(&info->mm_lock);
>> +
>> +	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
>> +	fb_pgprotect(file, vma, start);
>> +
>> +	return vm_iomap_memory(vma, start, len);
>> +}
>> +
>> +static int fb_open(struct inode *inode, struct file *file)
>> +__acquires(&info->lock)
>> +__releases(&info->lock)
>> +{
>> +	int fbidx = iminor(inode);
>> +	struct fb_info *info;
>> +	int res = 0;
>> +
>> +	info = get_fb_info(fbidx);
>> +	if (!info) {
>> +		request_module("fb%d", fbidx);
>> +		info = get_fb_info(fbidx);
>> +		if (!info)
>> +			return -ENODEV;
>> +	}
>> +	if (IS_ERR(info))
>> +		return PTR_ERR(info);
>> +
>> +	lock_fb_info(info);
>> +	if (!try_module_get(info->fbops->owner)) {
>> +		res = -ENODEV;
>> +		goto out;
>> +	}
>> +	file->private_data = info;
>> +	if (info->fbops->fb_open) {
>> +		res = info->fbops->fb_open(info, 1);
>> +		if (res)
>> +			module_put(info->fbops->owner);
>> +	}
>> +#ifdef CONFIG_FB_DEFERRED_IO
>> +	if (info->fbdefio)
>> +		fb_deferred_io_open(info, inode, file);
>> +#endif
>> +out:
>> +	unlock_fb_info(info);
>> +	if (res)
>> +		put_fb_info(info);
>> +	return res;
>> +}
>> +
>> +static int fb_release(struct inode *inode, struct file *file)
>> +__acquires(&info->lock)
>> +__releases(&info->lock)
>> +{
>> +	struct fb_info * const info = file->private_data;
>> +
>> +	lock_fb_info(info);
>> +#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
>> +	if (info->fbdefio)
>> +		fb_deferred_io_release(info);
>> +#endif
>> +	if (info->fbops->fb_release)
>> +		info->fbops->fb_release(info, 1);
>> +	module_put(info->fbops->owner);
>> +	unlock_fb_info(info);
>> +	put_fb_info(info);
>> +	return 0;
>> +}
>> +
>> +#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
>> +static unsigned long get_fb_unmapped_area(struct file *filp,
>> +				   unsigned long addr, unsigned long len,
>> +				   unsigned long pgoff, unsigned long flags)
>> +{
>> +	struct fb_info * const info = filp->private_data;
>> +	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
>> +
>> +	if (pgoff > fb_size || len > fb_size - pgoff)
>> +		return -EINVAL;
>> +
>> +	return (unsigned long)info->screen_base + pgoff;
>> +}
>> +#endif
>> +
>> +static const struct file_operations fb_fops = {
>> +	.owner = THIS_MODULE,
>> +	.read = fb_read,
>> +	.write = fb_write,
>> +	.unlocked_ioctl = fb_ioctl,
>> +#ifdef CONFIG_COMPAT
>> +	.compat_ioctl = fb_compat_ioctl,
>> +#endif
>> +	.mmap = fb_mmap,
>> +	.open = fb_open,
>> +	.release = fb_release,
>> +#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
>> +	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
>> +	 !defined(CONFIG_MMU))
>> +	.get_unmapped_area = get_fb_unmapped_area,
>> +#endif
>> +#ifdef CONFIG_FB_DEFERRED_IO
>> +	.fsync = fb_deferred_io_fsync,
>> +#endif
>> +	.llseek = default_llseek,
>> +};
>> +
>> +int fb_register_chrdev(void)
>> +{
>> +	int ret;
>> +
>> +	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
>> +	if (ret) {
>> +		pr_err("Unable to get major %d for fb devs\n", FB_MAJOR);
>> +		return ret;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +void fb_unregister_chrdev(void)
>> +{
>> +	unregister_chrdev(FB_MAJOR, "fb");
>> +}
>> diff --git a/drivers/video/fbdev/core/fb_internal.h b/drivers/video/fbdev/core/fb_internal.h
>> index 51f7c9f04e45..abe06c9da36e 100644
>> --- a/drivers/video/fbdev/core/fb_internal.h
>> +++ b/drivers/video/fbdev/core/fb_internal.h
>> @@ -6,10 +6,16 @@
>>   #include <linux/fb.h>
>>   #include <linux/mutex.h>
>>   
>> +/* fb_devfs.c */
>> +int fb_register_chrdev(void);
>> +void fb_unregister_chrdev(void);
>> +
>>   /* fbmem.c */
>>   extern struct mutex registration_lock;
>>   extern struct fb_info *registered_fb[FB_MAX];
>>   extern int num_registered_fb;
>> +struct fb_info *get_fb_info(unsigned int idx);
>> +void put_fb_info(struct fb_info *fb_info);
> The only users of get_fb_info() and put_fb_info() are now in fb_devfs.
> So consider moving these two helpers too.
> 
>>   
>>   /* fb_procfs.c */
>>   int fb_init_procfs(void);
>> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
>> index de1e45240161..2d26ac46337b 100644
>> --- a/drivers/video/fbdev/core/fbmem.c
>> +++ b/drivers/video/fbdev/core/fbmem.c
>> @@ -17,7 +17,6 @@
>>   #include <linux/types.h>
>>   #include <linux/errno.h>
>>   #include <linux/kernel.h>
>> -#include <linux/major.h>
>>   #include <linux/slab.h>
>>   #include <linux/mm.h>
>>   #include <linux/mman.h>
>> @@ -54,7 +53,7 @@ bool fb_center_logo __read_mostly;
>>   
>>   int fb_logo_count __read_mostly = -1;
>>   
>> -static struct fb_info *get_fb_info(unsigned int idx)
>> +struct fb_info *get_fb_info(unsigned int idx)
>>   {
>>   	struct fb_info *fb_info;
>>   
>> @@ -70,7 +69,7 @@ static struct fb_info *get_fb_info(unsigned int idx)
>>   	return fb_info;
>>   }
>>   
>> -static void put_fb_info(struct fb_info *fb_info)
>> +void put_fb_info(struct fb_info *fb_info)
>>   {
>>   	if (!refcount_dec_and_test(&fb_info->count))
>>   		return;
>> @@ -699,59 +698,6 @@ int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
>>   EXPORT_SYMBOL(fb_prepare_logo);
>>   EXPORT_SYMBOL(fb_show_logo);
> 
> Reminds me - consider moving logo stuff to a fb_logo file.
> This would reduce fbmem with a lot of lines, and it is separate.
> But it is outside the goal of this patchset.
> 
>>   
>> -/*
>> - * We hold a reference to the fb_info in file->private_data,
>> - * but if the current registered fb has changed, we don't
>> - * actually want to use it.
>> - *
>> - * So look up the fb_info using the inode minor number,
>> - * and just verify it against the reference we have.
>> - */
>> -static struct fb_info *file_fb_info(struct file *file)
>> -{
>> -	struct inode *inode = file_inode(file);
>> -	int fbidx = iminor(inode);
>> -	struct fb_info *info = registered_fb[fbidx];
>> -
>> -	if (info != file->private_data)
>> -		info = NULL;
>> -	return info;
>> -}
>> -
>> -static ssize_t
>> -fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> -{
>> -	struct fb_info *info = file_fb_info(file);
>> -
>> -	if (!info)
>> -		return -ENODEV;
>> -
>> -	if (info->state != FBINFO_STATE_RUNNING)
>> -		return -EPERM;
>> -
>> -	if (info->fbops->fb_read)
>> -		return info->fbops->fb_read(info, buf, count, ppos);
>> -
>> -	return fb_io_read(info, buf, count, ppos);
>> -}
>> -
>> -static ssize_t
>> -fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
>> -{
>> -	struct fb_info *info = file_fb_info(file);
>> -
>> -	if (!info)
>> -		return -ENODEV;
>> -
>> -	if (info->state != FBINFO_STATE_RUNNING)
>> -		return -EPERM;
>> -
>> -	if (info->fbops->fb_write)
>> -		return info->fbops->fb_write(info, buf, count, ppos);
>> -
>> -	return fb_io_write(info, buf, count, ppos);
>> -}
>> -
>>   int
>>   fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
>>   {
>> @@ -951,416 +897,6 @@ fb_blank(struct fb_info *info, int blank)
>>   }
>>   EXPORT_SYMBOL(fb_blank);
>>   
>> -static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>> -			unsigned long arg)
>> -{
>> -	const struct fb_ops *fb;
>> -	struct fb_var_screeninfo var;
>> -	struct fb_fix_screeninfo fix;
>> -	struct fb_cmap cmap_from;
>> -	struct fb_cmap_user cmap;
>> -	void __user *argp = (void __user *)arg;
>> -	long ret = 0;
>> -
>> -	switch (cmd) {
>> -	case FBIOGET_VSCREENINFO:
>> -		lock_fb_info(info);
>> -		var = info->var;
>> -		unlock_fb_info(info);
>> -
>> -		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
>> -		break;
>> -	case FBIOPUT_VSCREENINFO:
>> -		if (copy_from_user(&var, argp, sizeof(var)))
>> -			return -EFAULT;
>> -		/* only for kernel-internal use */
>> -		var.activate &= ~FB_ACTIVATE_KD_TEXT;
>> -		console_lock();
>> -		lock_fb_info(info);
>> -		ret = fbcon_modechange_possible(info, &var);
>> -		if (!ret)
>> -			ret = fb_set_var(info, &var);
>> -		if (!ret)
>> -			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
>> -		unlock_fb_info(info);
>> -		console_unlock();
>> -		if (!ret && copy_to_user(argp, &var, sizeof(var)))
>> -			ret = -EFAULT;
>> -		break;
>> -	case FBIOGET_FSCREENINFO:
>> -		lock_fb_info(info);
>> -		memcpy(&fix, &info->fix, sizeof(fix));
>> -		if (info->flags & FBINFO_HIDE_SMEM_START)
>> -			fix.smem_start = 0;
>> -		unlock_fb_info(info);
>> -
>> -		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
>> -		break;
>> -	case FBIOPUTCMAP:
>> -		if (copy_from_user(&cmap, argp, sizeof(cmap)))
>> -			return -EFAULT;
>> -		ret = fb_set_user_cmap(&cmap, info);
>> -		break;
>> -	case FBIOGETCMAP:
>> -		if (copy_from_user(&cmap, argp, sizeof(cmap)))
>> -			return -EFAULT;
>> -		lock_fb_info(info);
>> -		cmap_from = info->cmap;
>> -		unlock_fb_info(info);
>> -		ret = fb_cmap_to_user(&cmap_from, &cmap);
>> -		break;
>> -	case FBIOPAN_DISPLAY:
>> -		if (copy_from_user(&var, argp, sizeof(var)))
>> -			return -EFAULT;
>> -		console_lock();
>> -		lock_fb_info(info);
>> -		ret = fb_pan_display(info, &var);
>> -		unlock_fb_info(info);
>> -		console_unlock();
>> -		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
>> -			return -EFAULT;
>> -		break;
>> -	case FBIO_CURSOR:
>> -		ret = -EINVAL;
>> -		break;
>> -	case FBIOGET_CON2FBMAP:
>> -		ret = fbcon_get_con2fb_map_ioctl(argp);
>> -		break;
>> -	case FBIOPUT_CON2FBMAP:
>> -		ret = fbcon_set_con2fb_map_ioctl(argp);
>> -		break;
>> -	case FBIOBLANK:
>> -		if (arg > FB_BLANK_POWERDOWN)
>> -			return -EINVAL;
>> -		console_lock();
>> -		lock_fb_info(info);
>> -		ret = fb_blank(info, arg);
>> -		/* might again call into fb_blank */
>> -		fbcon_fb_blanked(info, arg);
>> -		unlock_fb_info(info);
>> -		console_unlock();
>> -		break;
>> -	default:
>> -		lock_fb_info(info);
>> -		fb = info->fbops;
>> -		if (fb->fb_ioctl)
>> -			ret = fb->fb_ioctl(info, cmd, arg);
>> -		else
>> -			ret = -ENOTTY;
>> -		unlock_fb_info(info);
>> -	}
>> -	return ret;
>> -}
>> -
>> -static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>> -{
>> -	struct fb_info *info = file_fb_info(file);
>> -
>> -	if (!info)
>> -		return -ENODEV;
>> -	return do_fb_ioctl(info, cmd, arg);
>> -}
>> -
>> -#ifdef CONFIG_COMPAT
>> -struct fb_fix_screeninfo32 {
>> -	char			id[16];
>> -	compat_caddr_t		smem_start;
>> -	u32			smem_len;
>> -	u32			type;
>> -	u32			type_aux;
>> -	u32			visual;
>> -	u16			xpanstep;
>> -	u16			ypanstep;
>> -	u16			ywrapstep;
>> -	u32			line_length;
>> -	compat_caddr_t		mmio_start;
>> -	u32			mmio_len;
>> -	u32			accel;
>> -	u16			reserved[3];
>> -};
>> -
>> -struct fb_cmap32 {
>> -	u32			start;
>> -	u32			len;
>> -	compat_caddr_t	red;
>> -	compat_caddr_t	green;
>> -	compat_caddr_t	blue;
>> -	compat_caddr_t	transp;
>> -};
>> -
>> -static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
>> -			  unsigned long arg)
>> -{
>> -	struct fb_cmap32 cmap32;
>> -	struct fb_cmap cmap_from;
>> -	struct fb_cmap_user cmap;
>> -
>> -	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
>> -		return -EFAULT;
>> -
>> -	cmap = (struct fb_cmap_user) {
>> -		.start	= cmap32.start,
>> -		.len	= cmap32.len,
>> -		.red	= compat_ptr(cmap32.red),
>> -		.green	= compat_ptr(cmap32.green),
>> -		.blue	= compat_ptr(cmap32.blue),
>> -		.transp	= compat_ptr(cmap32.transp),
>> -	};
>> -
>> -	if (cmd == FBIOPUTCMAP)
>> -		return fb_set_user_cmap(&cmap, info);
>> -
>> -	lock_fb_info(info);
>> -	cmap_from = info->cmap;
>> -	unlock_fb_info(info);
>> -
>> -	return fb_cmap_to_user(&cmap_from, &cmap);
>> -}
>> -
>> -static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
>> -				  struct fb_fix_screeninfo32 __user *fix32)
>> -{
>> -	__u32 data;
>> -	int err;
>> -
>> -	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
>> -
>> -	data = (__u32) (unsigned long) fix->smem_start;
>> -	err |= put_user(data, &fix32->smem_start);
>> -
>> -	err |= put_user(fix->smem_len, &fix32->smem_len);
>> -	err |= put_user(fix->type, &fix32->type);
>> -	err |= put_user(fix->type_aux, &fix32->type_aux);
>> -	err |= put_user(fix->visual, &fix32->visual);
>> -	err |= put_user(fix->xpanstep, &fix32->xpanstep);
>> -	err |= put_user(fix->ypanstep, &fix32->ypanstep);
>> -	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
>> -	err |= put_user(fix->line_length, &fix32->line_length);
>> -
>> -	data = (__u32) (unsigned long) fix->mmio_start;
>> -	err |= put_user(data, &fix32->mmio_start);
>> -
>> -	err |= put_user(fix->mmio_len, &fix32->mmio_len);
>> -	err |= put_user(fix->accel, &fix32->accel);
>> -	err |= copy_to_user(fix32->reserved, fix->reserved,
>> -			    sizeof(fix->reserved));
>> -
>> -	if (err)
>> -		return -EFAULT;
>> -	return 0;
>> -}
>> -
>> -static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
>> -			      unsigned long arg)
>> -{
>> -	struct fb_fix_screeninfo fix;
>> -
>> -	lock_fb_info(info);
>> -	fix = info->fix;
>> -	if (info->flags & FBINFO_HIDE_SMEM_START)
>> -		fix.smem_start = 0;
>> -	unlock_fb_info(info);
>> -	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
>> -}
>> -
>> -static long fb_compat_ioctl(struct file *file, unsigned int cmd,
>> -			    unsigned long arg)
>> -{
>> -	struct fb_info *info = file_fb_info(file);
>> -	const struct fb_ops *fb;
>> -	long ret = -ENOIOCTLCMD;
>> -
>> -	if (!info)
>> -		return -ENODEV;
>> -	fb = info->fbops;
>> -	switch(cmd) {
>> -	case FBIOGET_VSCREENINFO:
>> -	case FBIOPUT_VSCREENINFO:
>> -	case FBIOPAN_DISPLAY:
>> -	case FBIOGET_CON2FBMAP:
>> -	case FBIOPUT_CON2FBMAP:
>> -		arg = (unsigned long) compat_ptr(arg);
>> -		fallthrough;
>> -	case FBIOBLANK:
>> -		ret = do_fb_ioctl(info, cmd, arg);
>> -		break;
>> -
>> -	case FBIOGET_FSCREENINFO:
>> -		ret = fb_get_fscreeninfo(info, cmd, arg);
>> -		break;
>> -
>> -	case FBIOGETCMAP:
>> -	case FBIOPUTCMAP:
>> -		ret = fb_getput_cmap(info, cmd, arg);
>> -		break;
>> -
>> -	default:
>> -		if (fb->fb_compat_ioctl)
>> -			ret = fb->fb_compat_ioctl(info, cmd, arg);
>> -		break;
>> -	}
>> -	return ret;
>> -}
>> -#endif
>> -
>> -static int
>> -fb_mmap(struct file *file, struct vm_area_struct * vma)
>> -{
>> -	struct fb_info *info = file_fb_info(file);
>> -	unsigned long mmio_pgoff;
>> -	unsigned long start;
>> -	u32 len;
>> -
>> -	if (!info)
>> -		return -ENODEV;
>> -	mutex_lock(&info->mm_lock);
>> -
>> -	if (info->fbops->fb_mmap) {
>> -		int res;
>> -
>> -		/*
>> -		 * The framebuffer needs to be accessed decrypted, be sure
>> -		 * SME protection is removed ahead of the call
>> -		 */
>> -		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
>> -		res = info->fbops->fb_mmap(info, vma);
>> -		mutex_unlock(&info->mm_lock);
>> -		return res;
>> -#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
>> -	} else if (info->fbdefio) {
>> -		/*
>> -		 * FB deferred I/O wants you to handle mmap in your drivers. At a
>> -		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
>> -		 */
>> -		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
>> -		mutex_unlock(&info->mm_lock);
>> -		return -ENODEV;
>> -#endif
>> -	}
>> -
>> -	/*
>> -	 * Ugh. This can be either the frame buffer mapping, or
>> -	 * if pgoff points past it, the mmio mapping.
>> -	 */
>> -	start = info->fix.smem_start;
>> -	len = info->fix.smem_len;
>> -	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
>> -	if (vma->vm_pgoff >= mmio_pgoff) {
>> -		if (info->var.accel_flags) {
>> -			mutex_unlock(&info->mm_lock);
>> -			return -EINVAL;
>> -		}
>> -
>> -		vma->vm_pgoff -= mmio_pgoff;
>> -		start = info->fix.mmio_start;
>> -		len = info->fix.mmio_len;
>> -	}
>> -	mutex_unlock(&info->mm_lock);
>> -
>> -	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
>> -	fb_pgprotect(file, vma, start);
>> -
>> -	return vm_iomap_memory(vma, start, len);
>> -}
>> -
>> -static int
>> -fb_open(struct inode *inode, struct file *file)
>> -__acquires(&info->lock)
>> -__releases(&info->lock)
>> -{
>> -	int fbidx = iminor(inode);
>> -	struct fb_info *info;
>> -	int res = 0;
>> -
>> -	info = get_fb_info(fbidx);
>> -	if (!info) {
>> -		request_module("fb%d", fbidx);
>> -		info = get_fb_info(fbidx);
>> -		if (!info)
>> -			return -ENODEV;
>> -	}
>> -	if (IS_ERR(info))
>> -		return PTR_ERR(info);
>> -
>> -	lock_fb_info(info);
>> -	if (!try_module_get(info->fbops->owner)) {
>> -		res = -ENODEV;
>> -		goto out;
>> -	}
>> -	file->private_data = info;
>> -	if (info->fbops->fb_open) {
>> -		res = info->fbops->fb_open(info,1);
>> -		if (res)
>> -			module_put(info->fbops->owner);
>> -	}
>> -#ifdef CONFIG_FB_DEFERRED_IO
>> -	if (info->fbdefio)
>> -		fb_deferred_io_open(info, inode, file);
>> -#endif
>> -out:
>> -	unlock_fb_info(info);
>> -	if (res)
>> -		put_fb_info(info);
>> -	return res;
>> -}
>> -
>> -static int
>> -fb_release(struct inode *inode, struct file *file)
>> -__acquires(&info->lock)
>> -__releases(&info->lock)
>> -{
>> -	struct fb_info * const info = file->private_data;
>> -
>> -	lock_fb_info(info);
>> -#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
>> -	if (info->fbdefio)
>> -		fb_deferred_io_release(info);
>> -#endif
>> -	if (info->fbops->fb_release)
>> -		info->fbops->fb_release(info,1);
>> -	module_put(info->fbops->owner);
>> -	unlock_fb_info(info);
>> -	put_fb_info(info);
>> -	return 0;
>> -}
>> -
>> -#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
>> -static unsigned long get_fb_unmapped_area(struct file *filp,
>> -				   unsigned long addr, unsigned long len,
>> -				   unsigned long pgoff, unsigned long flags)
>> -{
>> -	struct fb_info * const info = filp->private_data;
>> -	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
>> -
>> -	if (pgoff > fb_size || len > fb_size - pgoff)
>> -		return -EINVAL;
>> -
>> -	return (unsigned long)info->screen_base + pgoff;
>> -}
>> -#endif
>> -
>> -static const struct file_operations fb_fops = {
>> -	.owner =	THIS_MODULE,
>> -	.read =		fb_read,
>> -	.write =	fb_write,
>> -	.unlocked_ioctl = fb_ioctl,
>> -#ifdef CONFIG_COMPAT
>> -	.compat_ioctl = fb_compat_ioctl,
>> -#endif
>> -	.mmap =		fb_mmap,
>> -	.open =		fb_open,
>> -	.release =	fb_release,
>> -#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
>> -	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
>> -	 !defined(CONFIG_MMU))
>> -	.get_unmapped_area = get_fb_unmapped_area,
>> -#endif
>> -#ifdef CONFIG_FB_DEFERRED_IO
>> -	.fsync =	fb_deferred_io_fsync,
>> -#endif
>> -	.llseek =	default_llseek,
>> -};
>> -
>>   struct class *fb_class;
>>   EXPORT_SYMBOL(fb_class);
>>   
>> @@ -1588,11 +1124,9 @@ fbmem_init(void)
>>   	if (ret)
>>   		return ret;
>>   
>> -	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
>> -	if (ret) {
>> -		printk("unable to get major %d for fb devs\n", FB_MAJOR);
>> +	ret = fb_register_chrdev();
>> +	if (ret)
>>   		goto err_chrdev;
>> -	}
>>   
>>   	fb_class = class_create("graphics");
>>   	if (IS_ERR(fb_class)) {
>> @@ -1607,7 +1141,7 @@ fbmem_init(void)
>>   	return 0;
>>   
>>   err_class:
>> -	unregister_chrdev(FB_MAJOR, "fb");
>> +	fb_unregister_chrdev();
>>   err_chrdev:
>>   	fb_cleanup_procfs();
>>   	return ret;
>> @@ -1622,7 +1156,7 @@ fbmem_exit(void)
>>   
>>   	fb_cleanup_procfs();
>>   	class_destroy(fb_class);
>> -	unregister_chrdev(FB_MAJOR, "fb");
>> +	fb_unregister_chrdev();
>>   }
>>   
>>   module_exit(fbmem_exit);
>> -- 
>> 2.40.1

Patch

diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile
index 665320160f70..125d24f50c36 100644
--- a/drivers/video/fbdev/core/Makefile
+++ b/drivers/video/fbdev/core/Makefile
@@ -2,6 +2,7 @@ 
 obj-$(CONFIG_FB_NOTIFY)           += fb_notify.o
 obj-$(CONFIG_FB)                  += fb.o
 fb-y                              := fb_backlight.o \
+                                     fb_devfs.o \
                                      fb_info.o \
                                      fb_procfs.o \
                                      fbmem.o fbmon.o fbcmap.o fbsysfs.o \
diff --git a/drivers/video/fbdev/core/fb_devfs.c b/drivers/video/fbdev/core/fb_devfs.c
new file mode 100644
index 000000000000..5ab16cb24524
--- /dev/null
+++ b/drivers/video/fbdev/core/fb_devfs.c
@@ -0,0 +1,484 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/console.h>
+#include <linux/fb.h>
+#include <linux/fbcon.h>
+#include <linux/major.h>
+
+#include "fb_internal.h"
+
+/*
+ * We hold a reference to the fb_info in file->private_data,
+ * but if the current registered fb has changed, we don't
+ * actually want to use it.
+ *
+ * So look up the fb_info using the inode minor number,
+ * and just verify it against the reference we have.
+ */
+static struct fb_info *file_fb_info(struct file *file)
+{
+	struct inode *inode = file_inode(file);
+	int fbidx = iminor(inode);
+	struct fb_info *info = registered_fb[fbidx];
+
+	if (info != file->private_data)
+		info = NULL;
+	return info;
+}
+
+static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct fb_info *info = file_fb_info(file);
+
+	if (!info)
+		return -ENODEV;
+
+	if (info->state != FBINFO_STATE_RUNNING)
+		return -EPERM;
+
+	if (info->fbops->fb_read)
+		return info->fbops->fb_read(info, buf, count, ppos);
+
+	return fb_io_read(info, buf, count, ppos);
+}
+
+static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct fb_info *info = file_fb_info(file);
+
+	if (!info)
+		return -ENODEV;
+
+	if (info->state != FBINFO_STATE_RUNNING)
+		return -EPERM;
+
+	if (info->fbops->fb_write)
+		return info->fbops->fb_write(info, buf, count, ppos);
+
+	return fb_io_write(info, buf, count, ppos);
+}
+
+static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
+			unsigned long arg)
+{
+	const struct fb_ops *fb;
+	struct fb_var_screeninfo var;
+	struct fb_fix_screeninfo fix;
+	struct fb_cmap cmap_from;
+	struct fb_cmap_user cmap;
+	void __user *argp = (void __user *)arg;
+	long ret = 0;
+
+	switch (cmd) {
+	case FBIOGET_VSCREENINFO:
+		lock_fb_info(info);
+		var = info->var;
+		unlock_fb_info(info);
+
+		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
+		break;
+	case FBIOPUT_VSCREENINFO:
+		if (copy_from_user(&var, argp, sizeof(var)))
+			return -EFAULT;
+		/* only for kernel-internal use */
+		var.activate &= ~FB_ACTIVATE_KD_TEXT;
+		console_lock();
+		lock_fb_info(info);
+		ret = fbcon_modechange_possible(info, &var);
+		if (!ret)
+			ret = fb_set_var(info, &var);
+		if (!ret)
+			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
+		unlock_fb_info(info);
+		console_unlock();
+		if (!ret && copy_to_user(argp, &var, sizeof(var)))
+			ret = -EFAULT;
+		break;
+	case FBIOGET_FSCREENINFO:
+		lock_fb_info(info);
+		memcpy(&fix, &info->fix, sizeof(fix));
+		if (info->flags & FBINFO_HIDE_SMEM_START)
+			fix.smem_start = 0;
+		unlock_fb_info(info);
+
+		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
+		break;
+	case FBIOPUTCMAP:
+		if (copy_from_user(&cmap, argp, sizeof(cmap)))
+			return -EFAULT;
+		ret = fb_set_user_cmap(&cmap, info);
+		break;
+	case FBIOGETCMAP:
+		if (copy_from_user(&cmap, argp, sizeof(cmap)))
+			return -EFAULT;
+		lock_fb_info(info);
+		cmap_from = info->cmap;
+		unlock_fb_info(info);
+		ret = fb_cmap_to_user(&cmap_from, &cmap);
+		break;
+	case FBIOPAN_DISPLAY:
+		if (copy_from_user(&var, argp, sizeof(var)))
+			return -EFAULT;
+		console_lock();
+		lock_fb_info(info);
+		ret = fb_pan_display(info, &var);
+		unlock_fb_info(info);
+		console_unlock();
+		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
+			return -EFAULT;
+		break;
+	case FBIO_CURSOR:
+		ret = -EINVAL;
+		break;
+	case FBIOGET_CON2FBMAP:
+		ret = fbcon_get_con2fb_map_ioctl(argp);
+		break;
+	case FBIOPUT_CON2FBMAP:
+		ret = fbcon_set_con2fb_map_ioctl(argp);
+		break;
+	case FBIOBLANK:
+		if (arg > FB_BLANK_POWERDOWN)
+			return -EINVAL;
+		console_lock();
+		lock_fb_info(info);
+		ret = fb_blank(info, arg);
+		/* might again call into fb_blank */
+		fbcon_fb_blanked(info, arg);
+		unlock_fb_info(info);
+		console_unlock();
+		break;
+	default:
+		lock_fb_info(info);
+		fb = info->fbops;
+		if (fb->fb_ioctl)
+			ret = fb->fb_ioctl(info, cmd, arg);
+		else
+			ret = -ENOTTY;
+		unlock_fb_info(info);
+	}
+	return ret;
+}
+
+static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct fb_info *info = file_fb_info(file);
+
+	if (!info)
+		return -ENODEV;
+	return do_fb_ioctl(info, cmd, arg);
+}
+
+#ifdef CONFIG_COMPAT
+struct fb_fix_screeninfo32 {
+	char			id[16];
+	compat_caddr_t		smem_start;
+	u32			smem_len;
+	u32			type;
+	u32			type_aux;
+	u32			visual;
+	u16			xpanstep;
+	u16			ypanstep;
+	u16			ywrapstep;
+	u32			line_length;
+	compat_caddr_t		mmio_start;
+	u32			mmio_len;
+	u32			accel;
+	u16			reserved[3];
+};
+
+struct fb_cmap32 {
+	u32			start;
+	u32			len;
+	compat_caddr_t	red;
+	compat_caddr_t	green;
+	compat_caddr_t	blue;
+	compat_caddr_t	transp;
+};
+
+static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
+			  unsigned long arg)
+{
+	struct fb_cmap32 cmap32;
+	struct fb_cmap cmap_from;
+	struct fb_cmap_user cmap;
+
+	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
+		return -EFAULT;
+
+	cmap = (struct fb_cmap_user) {
+		.start	= cmap32.start,
+		.len	= cmap32.len,
+		.red	= compat_ptr(cmap32.red),
+		.green	= compat_ptr(cmap32.green),
+		.blue	= compat_ptr(cmap32.blue),
+		.transp	= compat_ptr(cmap32.transp),
+	};
+
+	if (cmd == FBIOPUTCMAP)
+		return fb_set_user_cmap(&cmap, info);
+
+	lock_fb_info(info);
+	cmap_from = info->cmap;
+	unlock_fb_info(info);
+
+	return fb_cmap_to_user(&cmap_from, &cmap);
+}
+
+static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
+				  struct fb_fix_screeninfo32 __user *fix32)
+{
+	__u32 data;
+	int err;
+
+	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
+
+	data = (__u32) (unsigned long) fix->smem_start;
+	err |= put_user(data, &fix32->smem_start);
+
+	err |= put_user(fix->smem_len, &fix32->smem_len);
+	err |= put_user(fix->type, &fix32->type);
+	err |= put_user(fix->type_aux, &fix32->type_aux);
+	err |= put_user(fix->visual, &fix32->visual);
+	err |= put_user(fix->xpanstep, &fix32->xpanstep);
+	err |= put_user(fix->ypanstep, &fix32->ypanstep);
+	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
+	err |= put_user(fix->line_length, &fix32->line_length);
+
+	data = (__u32) (unsigned long) fix->mmio_start;
+	err |= put_user(data, &fix32->mmio_start);
+
+	err |= put_user(fix->mmio_len, &fix32->mmio_len);
+	err |= put_user(fix->accel, &fix32->accel);
+	err |= copy_to_user(fix32->reserved, fix->reserved,
+			    sizeof(fix->reserved));
+
+	if (err)
+		return -EFAULT;
+	return 0;
+}
+
+static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
+			      unsigned long arg)
+{
+	struct fb_fix_screeninfo fix;
+
+	lock_fb_info(info);
+	fix = info->fix;
+	if (info->flags & FBINFO_HIDE_SMEM_START)
+		fix.smem_start = 0;
+	unlock_fb_info(info);
+	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
+}
+
+static long fb_compat_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg)
+{
+	struct fb_info *info = file_fb_info(file);
+	const struct fb_ops *fb;
+	long ret = -ENOIOCTLCMD;
+
+	if (!info)
+		return -ENODEV;
+	fb = info->fbops;
+	switch (cmd) {
+	case FBIOGET_VSCREENINFO:
+	case FBIOPUT_VSCREENINFO:
+	case FBIOPAN_DISPLAY:
+	case FBIOGET_CON2FBMAP:
+	case FBIOPUT_CON2FBMAP:
+		arg = (unsigned long) compat_ptr(arg);
+		fallthrough;
+	case FBIOBLANK:
+		ret = do_fb_ioctl(info, cmd, arg);
+		break;
+
+	case FBIOGET_FSCREENINFO:
+		ret = fb_get_fscreeninfo(info, cmd, arg);
+		break;
+
+	case FBIOGETCMAP:
+	case FBIOPUTCMAP:
+		ret = fb_getput_cmap(info, cmd, arg);
+		break;
+
+	default:
+		if (fb->fb_compat_ioctl)
+			ret = fb->fb_compat_ioctl(info, cmd, arg);
+		break;
+	}
+	return ret;
+}
+#endif
+
+static int fb_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct fb_info *info = file_fb_info(file);
+	unsigned long mmio_pgoff;
+	unsigned long start;
+	u32 len;
+
+	if (!info)
+		return -ENODEV;
+	mutex_lock(&info->mm_lock);
+
+	if (info->fbops->fb_mmap) {
+		int res;
+
+		/*
+		 * The framebuffer needs to be accessed decrypted, be sure
+		 * SME protection is removed ahead of the call
+		 */
+		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
+		res = info->fbops->fb_mmap(info, vma);
+		mutex_unlock(&info->mm_lock);
+		return res;
+#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
+	} else if (info->fbdefio) {
+		/*
+		 * FB deferred I/O wants you to handle mmap in your drivers. At a
+		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
+		 */
+		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
+		mutex_unlock(&info->mm_lock);
+		return -ENODEV;
+#endif
+	}
+
+	/*
+	 * Ugh. This can be either the frame buffer mapping, or
+	 * if pgoff points past it, the mmio mapping.
+	 */
+	start = info->fix.smem_start;
+	len = info->fix.smem_len;
+	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
+	if (vma->vm_pgoff >= mmio_pgoff) {
+		if (info->var.accel_flags) {
+			mutex_unlock(&info->mm_lock);
+			return -EINVAL;
+		}
+
+		vma->vm_pgoff -= mmio_pgoff;
+		start = info->fix.mmio_start;
+		len = info->fix.mmio_len;
+	}
+	mutex_unlock(&info->mm_lock);
+
+	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+	fb_pgprotect(file, vma, start);
+
+	return vm_iomap_memory(vma, start, len);
+}
+
+static int fb_open(struct inode *inode, struct file *file)
+__acquires(&info->lock)
+__releases(&info->lock)
+{
+	int fbidx = iminor(inode);
+	struct fb_info *info;
+	int res = 0;
+
+	info = get_fb_info(fbidx);
+	if (!info) {
+		request_module("fb%d", fbidx);
+		info = get_fb_info(fbidx);
+		if (!info)
+			return -ENODEV;
+	}
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	lock_fb_info(info);
+	if (!try_module_get(info->fbops->owner)) {
+		res = -ENODEV;
+		goto out;
+	}
+	file->private_data = info;
+	if (info->fbops->fb_open) {
+		res = info->fbops->fb_open(info, 1);
+		if (res)
+			module_put(info->fbops->owner);
+	}
+#ifdef CONFIG_FB_DEFERRED_IO
+	if (info->fbdefio)
+		fb_deferred_io_open(info, inode, file);
+#endif
+out:
+	unlock_fb_info(info);
+	if (res)
+		put_fb_info(info);
+	return res;
+}
+
+static int fb_release(struct inode *inode, struct file *file)
+__acquires(&info->lock)
+__releases(&info->lock)
+{
+	struct fb_info * const info = file->private_data;
+
+	lock_fb_info(info);
+#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
+	if (info->fbdefio)
+		fb_deferred_io_release(info);
+#endif
+	if (info->fbops->fb_release)
+		info->fbops->fb_release(info, 1);
+	module_put(info->fbops->owner);
+	unlock_fb_info(info);
+	put_fb_info(info);
+	return 0;
+}
+
+#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
+static unsigned long get_fb_unmapped_area(struct file *filp,
+				   unsigned long addr, unsigned long len,
+				   unsigned long pgoff, unsigned long flags)
+{
+	struct fb_info * const info = filp->private_data;
+	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
+
+	if (pgoff > fb_size || len > fb_size - pgoff)
+		return -EINVAL;
+
+	return (unsigned long)info->screen_base + pgoff;
+}
+#endif
+
+static const struct file_operations fb_fops = {
+	.owner = THIS_MODULE,
+	.read = fb_read,
+	.write = fb_write,
+	.unlocked_ioctl = fb_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = fb_compat_ioctl,
+#endif
+	.mmap = fb_mmap,
+	.open = fb_open,
+	.release = fb_release,
+#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
+	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
+	 !defined(CONFIG_MMU))
+	.get_unmapped_area = get_fb_unmapped_area,
+#endif
+#ifdef CONFIG_FB_DEFERRED_IO
+	.fsync = fb_deferred_io_fsync,
+#endif
+	.llseek = default_llseek,
+};
+
+int fb_register_chrdev(void)
+{
+	int ret;
+
+	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
+	if (ret) {
+		pr_err("Unable to get major %d for fb devs\n", FB_MAJOR);
+		return ret;
+	}
+
+	return ret;
+}
+
+void fb_unregister_chrdev(void)
+{
+	unregister_chrdev(FB_MAJOR, "fb");
+}
diff --git a/drivers/video/fbdev/core/fb_internal.h b/drivers/video/fbdev/core/fb_internal.h
index 51f7c9f04e45..abe06c9da36e 100644
--- a/drivers/video/fbdev/core/fb_internal.h
+++ b/drivers/video/fbdev/core/fb_internal.h
@@ -6,10 +6,16 @@ 
 #include <linux/fb.h>
 #include <linux/mutex.h>
 
+/* fb_devfs.c */
+int fb_register_chrdev(void);
+void fb_unregister_chrdev(void);
+
 /* fbmem.c */
 extern struct mutex registration_lock;
 extern struct fb_info *registered_fb[FB_MAX];
 extern int num_registered_fb;
+struct fb_info *get_fb_info(unsigned int idx);
+void put_fb_info(struct fb_info *fb_info);
 
 /* fb_procfs.c */
 int fb_init_procfs(void);
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index de1e45240161..2d26ac46337b 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -17,7 +17,6 @@ 
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
-#include <linux/major.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
@@ -54,7 +53,7 @@  bool fb_center_logo __read_mostly;
 
 int fb_logo_count __read_mostly = -1;
 
-static struct fb_info *get_fb_info(unsigned int idx)
+struct fb_info *get_fb_info(unsigned int idx)
 {
 	struct fb_info *fb_info;
 
@@ -70,7 +69,7 @@  static struct fb_info *get_fb_info(unsigned int idx)
 	return fb_info;
 }
 
-static void put_fb_info(struct fb_info *fb_info)
+void put_fb_info(struct fb_info *fb_info)
 {
 	if (!refcount_dec_and_test(&fb_info->count))
 		return;
@@ -699,59 +698,6 @@  int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
 EXPORT_SYMBOL(fb_prepare_logo);
 EXPORT_SYMBOL(fb_show_logo);
 
-/*
- * We hold a reference to the fb_info in file->private_data,
- * but if the current registered fb has changed, we don't
- * actually want to use it.
- *
- * So look up the fb_info using the inode minor number,
- * and just verify it against the reference we have.
- */
-static struct fb_info *file_fb_info(struct file *file)
-{
-	struct inode *inode = file_inode(file);
-	int fbidx = iminor(inode);
-	struct fb_info *info = registered_fb[fbidx];
-
-	if (info != file->private_data)
-		info = NULL;
-	return info;
-}
-
-static ssize_t
-fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
-{
-	struct fb_info *info = file_fb_info(file);
-
-	if (!info)
-		return -ENODEV;
-
-	if (info->state != FBINFO_STATE_RUNNING)
-		return -EPERM;
-
-	if (info->fbops->fb_read)
-		return info->fbops->fb_read(info, buf, count, ppos);
-
-	return fb_io_read(info, buf, count, ppos);
-}
-
-static ssize_t
-fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
-{
-	struct fb_info *info = file_fb_info(file);
-
-	if (!info)
-		return -ENODEV;
-
-	if (info->state != FBINFO_STATE_RUNNING)
-		return -EPERM;
-
-	if (info->fbops->fb_write)
-		return info->fbops->fb_write(info, buf, count, ppos);
-
-	return fb_io_write(info, buf, count, ppos);
-}
-
 int
 fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
 {
@@ -951,416 +897,6 @@  fb_blank(struct fb_info *info, int blank)
 }
 EXPORT_SYMBOL(fb_blank);
 
-static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
-			unsigned long arg)
-{
-	const struct fb_ops *fb;
-	struct fb_var_screeninfo var;
-	struct fb_fix_screeninfo fix;
-	struct fb_cmap cmap_from;
-	struct fb_cmap_user cmap;
-	void __user *argp = (void __user *)arg;
-	long ret = 0;
-
-	switch (cmd) {
-	case FBIOGET_VSCREENINFO:
-		lock_fb_info(info);
-		var = info->var;
-		unlock_fb_info(info);
-
-		ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
-		break;
-	case FBIOPUT_VSCREENINFO:
-		if (copy_from_user(&var, argp, sizeof(var)))
-			return -EFAULT;
-		/* only for kernel-internal use */
-		var.activate &= ~FB_ACTIVATE_KD_TEXT;
-		console_lock();
-		lock_fb_info(info);
-		ret = fbcon_modechange_possible(info, &var);
-		if (!ret)
-			ret = fb_set_var(info, &var);
-		if (!ret)
-			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
-		unlock_fb_info(info);
-		console_unlock();
-		if (!ret && copy_to_user(argp, &var, sizeof(var)))
-			ret = -EFAULT;
-		break;
-	case FBIOGET_FSCREENINFO:
-		lock_fb_info(info);
-		memcpy(&fix, &info->fix, sizeof(fix));
-		if (info->flags & FBINFO_HIDE_SMEM_START)
-			fix.smem_start = 0;
-		unlock_fb_info(info);
-
-		ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
-		break;
-	case FBIOPUTCMAP:
-		if (copy_from_user(&cmap, argp, sizeof(cmap)))
-			return -EFAULT;
-		ret = fb_set_user_cmap(&cmap, info);
-		break;
-	case FBIOGETCMAP:
-		if (copy_from_user(&cmap, argp, sizeof(cmap)))
-			return -EFAULT;
-		lock_fb_info(info);
-		cmap_from = info->cmap;
-		unlock_fb_info(info);
-		ret = fb_cmap_to_user(&cmap_from, &cmap);
-		break;
-	case FBIOPAN_DISPLAY:
-		if (copy_from_user(&var, argp, sizeof(var)))
-			return -EFAULT;
-		console_lock();
-		lock_fb_info(info);
-		ret = fb_pan_display(info, &var);
-		unlock_fb_info(info);
-		console_unlock();
-		if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
-			return -EFAULT;
-		break;
-	case FBIO_CURSOR:
-		ret = -EINVAL;
-		break;
-	case FBIOGET_CON2FBMAP:
-		ret = fbcon_get_con2fb_map_ioctl(argp);
-		break;
-	case FBIOPUT_CON2FBMAP:
-		ret = fbcon_set_con2fb_map_ioctl(argp);
-		break;
-	case FBIOBLANK:
-		if (arg > FB_BLANK_POWERDOWN)
-			return -EINVAL;
-		console_lock();
-		lock_fb_info(info);
-		ret = fb_blank(info, arg);
-		/* might again call into fb_blank */
-		fbcon_fb_blanked(info, arg);
-		unlock_fb_info(info);
-		console_unlock();
-		break;
-	default:
-		lock_fb_info(info);
-		fb = info->fbops;
-		if (fb->fb_ioctl)
-			ret = fb->fb_ioctl(info, cmd, arg);
-		else
-			ret = -ENOTTY;
-		unlock_fb_info(info);
-	}
-	return ret;
-}
-
-static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	struct fb_info *info = file_fb_info(file);
-
-	if (!info)
-		return -ENODEV;
-	return do_fb_ioctl(info, cmd, arg);
-}
-
-#ifdef CONFIG_COMPAT
-struct fb_fix_screeninfo32 {
-	char			id[16];
-	compat_caddr_t		smem_start;
-	u32			smem_len;
-	u32			type;
-	u32			type_aux;
-	u32			visual;
-	u16			xpanstep;
-	u16			ypanstep;
-	u16			ywrapstep;
-	u32			line_length;
-	compat_caddr_t		mmio_start;
-	u32			mmio_len;
-	u32			accel;
-	u16			reserved[3];
-};
-
-struct fb_cmap32 {
-	u32			start;
-	u32			len;
-	compat_caddr_t	red;
-	compat_caddr_t	green;
-	compat_caddr_t	blue;
-	compat_caddr_t	transp;
-};
-
-static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
-			  unsigned long arg)
-{
-	struct fb_cmap32 cmap32;
-	struct fb_cmap cmap_from;
-	struct fb_cmap_user cmap;
-
-	if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
-		return -EFAULT;
-
-	cmap = (struct fb_cmap_user) {
-		.start	= cmap32.start,
-		.len	= cmap32.len,
-		.red	= compat_ptr(cmap32.red),
-		.green	= compat_ptr(cmap32.green),
-		.blue	= compat_ptr(cmap32.blue),
-		.transp	= compat_ptr(cmap32.transp),
-	};
-
-	if (cmd == FBIOPUTCMAP)
-		return fb_set_user_cmap(&cmap, info);
-
-	lock_fb_info(info);
-	cmap_from = info->cmap;
-	unlock_fb_info(info);
-
-	return fb_cmap_to_user(&cmap_from, &cmap);
-}
-
-static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
-				  struct fb_fix_screeninfo32 __user *fix32)
-{
-	__u32 data;
-	int err;
-
-	err = copy_to_user(&fix32->id, &fix->id, sizeof(fix32->id));
-
-	data = (__u32) (unsigned long) fix->smem_start;
-	err |= put_user(data, &fix32->smem_start);
-
-	err |= put_user(fix->smem_len, &fix32->smem_len);
-	err |= put_user(fix->type, &fix32->type);
-	err |= put_user(fix->type_aux, &fix32->type_aux);
-	err |= put_user(fix->visual, &fix32->visual);
-	err |= put_user(fix->xpanstep, &fix32->xpanstep);
-	err |= put_user(fix->ypanstep, &fix32->ypanstep);
-	err |= put_user(fix->ywrapstep, &fix32->ywrapstep);
-	err |= put_user(fix->line_length, &fix32->line_length);
-
-	data = (__u32) (unsigned long) fix->mmio_start;
-	err |= put_user(data, &fix32->mmio_start);
-
-	err |= put_user(fix->mmio_len, &fix32->mmio_len);
-	err |= put_user(fix->accel, &fix32->accel);
-	err |= copy_to_user(fix32->reserved, fix->reserved,
-			    sizeof(fix->reserved));
-
-	if (err)
-		return -EFAULT;
-	return 0;
-}
-
-static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
-			      unsigned long arg)
-{
-	struct fb_fix_screeninfo fix;
-
-	lock_fb_info(info);
-	fix = info->fix;
-	if (info->flags & FBINFO_HIDE_SMEM_START)
-		fix.smem_start = 0;
-	unlock_fb_info(info);
-	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
-}
-
-static long fb_compat_ioctl(struct file *file, unsigned int cmd,
-			    unsigned long arg)
-{
-	struct fb_info *info = file_fb_info(file);
-	const struct fb_ops *fb;
-	long ret = -ENOIOCTLCMD;
-
-	if (!info)
-		return -ENODEV;
-	fb = info->fbops;
-	switch(cmd) {
-	case FBIOGET_VSCREENINFO:
-	case FBIOPUT_VSCREENINFO:
-	case FBIOPAN_DISPLAY:
-	case FBIOGET_CON2FBMAP:
-	case FBIOPUT_CON2FBMAP:
-		arg = (unsigned long) compat_ptr(arg);
-		fallthrough;
-	case FBIOBLANK:
-		ret = do_fb_ioctl(info, cmd, arg);
-		break;
-
-	case FBIOGET_FSCREENINFO:
-		ret = fb_get_fscreeninfo(info, cmd, arg);
-		break;
-
-	case FBIOGETCMAP:
-	case FBIOPUTCMAP:
-		ret = fb_getput_cmap(info, cmd, arg);
-		break;
-
-	default:
-		if (fb->fb_compat_ioctl)
-			ret = fb->fb_compat_ioctl(info, cmd, arg);
-		break;
-	}
-	return ret;
-}
-#endif
-
-static int
-fb_mmap(struct file *file, struct vm_area_struct * vma)
-{
-	struct fb_info *info = file_fb_info(file);
-	unsigned long mmio_pgoff;
-	unsigned long start;
-	u32 len;
-
-	if (!info)
-		return -ENODEV;
-	mutex_lock(&info->mm_lock);
-
-	if (info->fbops->fb_mmap) {
-		int res;
-
-		/*
-		 * The framebuffer needs to be accessed decrypted, be sure
-		 * SME protection is removed ahead of the call
-		 */
-		vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
-		res = info->fbops->fb_mmap(info, vma);
-		mutex_unlock(&info->mm_lock);
-		return res;
-#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
-	} else if (info->fbdefio) {
-		/*
-		 * FB deferred I/O wants you to handle mmap in your drivers. At a
-		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
-		 */
-		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
-		mutex_unlock(&info->mm_lock);
-		return -ENODEV;
-#endif
-	}
-
-	/*
-	 * Ugh. This can be either the frame buffer mapping, or
-	 * if pgoff points past it, the mmio mapping.
-	 */
-	start = info->fix.smem_start;
-	len = info->fix.smem_len;
-	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;
-	if (vma->vm_pgoff >= mmio_pgoff) {
-		if (info->var.accel_flags) {
-			mutex_unlock(&info->mm_lock);
-			return -EINVAL;
-		}
-
-		vma->vm_pgoff -= mmio_pgoff;
-		start = info->fix.mmio_start;
-		len = info->fix.mmio_len;
-	}
-	mutex_unlock(&info->mm_lock);
-
-	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-	fb_pgprotect(file, vma, start);
-
-	return vm_iomap_memory(vma, start, len);
-}
-
-static int
-fb_open(struct inode *inode, struct file *file)
-__acquires(&info->lock)
-__releases(&info->lock)
-{
-	int fbidx = iminor(inode);
-	struct fb_info *info;
-	int res = 0;
-
-	info = get_fb_info(fbidx);
-	if (!info) {
-		request_module("fb%d", fbidx);
-		info = get_fb_info(fbidx);
-		if (!info)
-			return -ENODEV;
-	}
-	if (IS_ERR(info))
-		return PTR_ERR(info);
-
-	lock_fb_info(info);
-	if (!try_module_get(info->fbops->owner)) {
-		res = -ENODEV;
-		goto out;
-	}
-	file->private_data = info;
-	if (info->fbops->fb_open) {
-		res = info->fbops->fb_open(info,1);
-		if (res)
-			module_put(info->fbops->owner);
-	}
-#ifdef CONFIG_FB_DEFERRED_IO
-	if (info->fbdefio)
-		fb_deferred_io_open(info, inode, file);
-#endif
-out:
-	unlock_fb_info(info);
-	if (res)
-		put_fb_info(info);
-	return res;
-}
-
-static int
-fb_release(struct inode *inode, struct file *file)
-__acquires(&info->lock)
-__releases(&info->lock)
-{
-	struct fb_info * const info = file->private_data;
-
-	lock_fb_info(info);
-#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
-	if (info->fbdefio)
-		fb_deferred_io_release(info);
-#endif
-	if (info->fbops->fb_release)
-		info->fbops->fb_release(info,1);
-	module_put(info->fbops->owner);
-	unlock_fb_info(info);
-	put_fb_info(info);
-	return 0;
-}
-
-#if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
-static unsigned long get_fb_unmapped_area(struct file *filp,
-				   unsigned long addr, unsigned long len,
-				   unsigned long pgoff, unsigned long flags)
-{
-	struct fb_info * const info = filp->private_data;
-	unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
-
-	if (pgoff > fb_size || len > fb_size - pgoff)
-		return -EINVAL;
-
-	return (unsigned long)info->screen_base + pgoff;
-}
-#endif
-
-static const struct file_operations fb_fops = {
-	.owner =	THIS_MODULE,
-	.read =		fb_read,
-	.write =	fb_write,
-	.unlocked_ioctl = fb_ioctl,
-#ifdef CONFIG_COMPAT
-	.compat_ioctl = fb_compat_ioctl,
-#endif
-	.mmap =		fb_mmap,
-	.open =		fb_open,
-	.release =	fb_release,
-#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) || \
-	(defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && \
-	 !defined(CONFIG_MMU))
-	.get_unmapped_area = get_fb_unmapped_area,
-#endif
-#ifdef CONFIG_FB_DEFERRED_IO
-	.fsync =	fb_deferred_io_fsync,
-#endif
-	.llseek =	default_llseek,
-};
-
 struct class *fb_class;
 EXPORT_SYMBOL(fb_class);
 
@@ -1588,11 +1124,9 @@  fbmem_init(void)
 	if (ret)
 		return ret;
 
-	ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
-	if (ret) {
-		printk("unable to get major %d for fb devs\n", FB_MAJOR);
+	ret = fb_register_chrdev();
+	if (ret)
 		goto err_chrdev;
-	}
 
 	fb_class = class_create("graphics");
 	if (IS_ERR(fb_class)) {
@@ -1607,7 +1141,7 @@  fbmem_init(void)
 	return 0;
 
 err_class:
-	unregister_chrdev(FB_MAJOR, "fb");
+	fb_unregister_chrdev();
 err_chrdev:
 	fb_cleanup_procfs();
 	return ret;
@@ -1622,7 +1156,7 @@  fbmem_exit(void)
 
 	fb_cleanup_procfs();
 	class_destroy(fb_class);
-	unregister_chrdev(FB_MAJOR, "fb");
+	fb_unregister_chrdev();
 }
 
 module_exit(fbmem_exit);