diff mbox series

PM / hibernate: Remove unnecessary compat ioctl overrides

Message ID 20200308032701.998434-1-ebiggers@kernel.org (mailing list archive)
State Mainlined, archived
Headers show
Series PM / hibernate: Remove unnecessary compat ioctl overrides | expand

Commit Message

Eric Biggers March 8, 2020, 3:27 a.m. UTC
From: Eric Biggers <ebiggers@google.com>

Since the SNAPSHOT_GET_IMAGE_SIZE, SNAPSHOT_AVAIL_SWAP_SIZE, and
SNAPSHOT_ALLOC_SWAP_PAGE ioctls produce an loff_t result, and loff_t is
always 64-bit even in the compat case, there's no reason to have the
special compat handling for these ioctls.  Just remove this unneeded
code so that these ioctls call into snapshot_ioctl() directly, doing
just the compat_ptr() conversion on the argument.

(This unnecessary code was also causing a KMSAN false positive.)

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 kernel/power/user.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

Comments

Rafael J. Wysocki March 14, 2020, 10:57 a.m. UTC | #1
On Sunday, March 8, 2020 4:27:01 AM CET Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Since the SNAPSHOT_GET_IMAGE_SIZE, SNAPSHOT_AVAIL_SWAP_SIZE, and
> SNAPSHOT_ALLOC_SWAP_PAGE ioctls produce an loff_t result, and loff_t is
> always 64-bit even in the compat case, there's no reason to have the
> special compat handling for these ioctls.  Just remove this unneeded
> code so that these ioctls call into snapshot_ioctl() directly, doing
> just the compat_ptr() conversion on the argument.
> 
> (This unnecessary code was also causing a KMSAN false positive.)
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  kernel/power/user.c | 16 +---------------
>  1 file changed, 1 insertion(+), 15 deletions(-)
> 
> diff --git a/kernel/power/user.c b/kernel/power/user.c
> index 77438954cc2b..58ed9478787f 100644
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -409,21 +409,7 @@ snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  	switch (cmd) {
>  	case SNAPSHOT_GET_IMAGE_SIZE:
>  	case SNAPSHOT_AVAIL_SWAP_SIZE:
> -	case SNAPSHOT_ALLOC_SWAP_PAGE: {
> -		compat_loff_t __user *uoffset = compat_ptr(arg);
> -		loff_t offset;
> -		mm_segment_t old_fs;
> -		int err;
> -
> -		old_fs = get_fs();
> -		set_fs(KERNEL_DS);
> -		err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
> -		set_fs(old_fs);
> -		if (!err && put_user(offset, uoffset))
> -			err = -EFAULT;
> -		return err;
> -	}
> -
> +	case SNAPSHOT_ALLOC_SWAP_PAGE:
>  	case SNAPSHOT_CREATE_IMAGE:
>  		return snapshot_ioctl(file, cmd,
>  				      (unsigned long) compat_ptr(arg));
> 

Applied as 5.7 material, thanks!
diff mbox series

Patch

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 77438954cc2b..58ed9478787f 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -409,21 +409,7 @@  snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	switch (cmd) {
 	case SNAPSHOT_GET_IMAGE_SIZE:
 	case SNAPSHOT_AVAIL_SWAP_SIZE:
-	case SNAPSHOT_ALLOC_SWAP_PAGE: {
-		compat_loff_t __user *uoffset = compat_ptr(arg);
-		loff_t offset;
-		mm_segment_t old_fs;
-		int err;
-
-		old_fs = get_fs();
-		set_fs(KERNEL_DS);
-		err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
-		set_fs(old_fs);
-		if (!err && put_user(offset, uoffset))
-			err = -EFAULT;
-		return err;
-	}
-
+	case SNAPSHOT_ALLOC_SWAP_PAGE:
 	case SNAPSHOT_CREATE_IMAGE:
 		return snapshot_ioctl(file, cmd,
 				      (unsigned long) compat_ptr(arg));