[v5,05/18] watchdog: cpwd: use generic compat_ptr_ioctl
diff mbox series

Message ID 20190814204259.120942-6-arnd@arndb.de
State New
Headers show
Series
  • compat_ioctl.c removal, part 2/3
Related show

Commit Message

Arnd Bergmann Aug. 14, 2019, 8:42 p.m. UTC
The cpwd_compat_ioctl() contains a bogus mutex that dates
back to a leftover BKL instance.

Simplify the implementation by using the new compat_ptr_ioctl()
helper function that will do the right thing for all calls
here.

Note that WIOCSTART/WIOCSTOP don't take any arguments, so
the compat_ptr() conversion is not needed here, but it also
doesn't hurt.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/watchdog/cpwd.c | 25 +------------------------
 1 file changed, 1 insertion(+), 24 deletions(-)

Comments

Guenter Roeck Aug. 15, 2019, 6:06 p.m. UTC | #1
On Wed, Aug 14, 2019 at 10:42:32PM +0200, Arnd Bergmann wrote:
> The cpwd_compat_ioctl() contains a bogus mutex that dates
> back to a leftover BKL instance.
> 
> Simplify the implementation by using the new compat_ptr_ioctl()
> helper function that will do the right thing for all calls
> here.
> 
> Note that WIOCSTART/WIOCSTOP don't take any arguments, so
> the compat_ptr() conversion is not needed here, but it also
> doesn't hurt.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Guenter Roeck Oct. 7, 2019, 11:28 p.m. UTC | #2
Arnd,

On Wed, Aug 14, 2019 at 10:42:32PM +0200, Arnd Bergmann wrote:
> The cpwd_compat_ioctl() contains a bogus mutex that dates
> back to a leftover BKL instance.
> 
> Simplify the implementation by using the new compat_ptr_ioctl()
> helper function that will do the right thing for all calls
> here.
> 
> Note that WIOCSTART/WIOCSTOP don't take any arguments, so
> the compat_ptr() conversion is not needed here, but it also
> doesn't hurt.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>

This patch made it into the kernel, but the infrastructure didn't make it.
Do we need to revert it ?

Guenter

> ---
>  drivers/watchdog/cpwd.c | 25 +------------------------
>  1 file changed, 1 insertion(+), 24 deletions(-)
> 
> diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
> index b973b31179df..9393be584e72 100644
> --- a/drivers/watchdog/cpwd.c
> +++ b/drivers/watchdog/cpwd.c
> @@ -473,29 +473,6 @@ static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>  	return 0;
>  }
>  
> -static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
> -			      unsigned long arg)
> -{
> -	int rval = -ENOIOCTLCMD;
> -
> -	switch (cmd) {
> -	/* solaris ioctls are specific to this driver */
> -	case WIOCSTART:
> -	case WIOCSTOP:
> -	case WIOCGSTAT:
> -		mutex_lock(&cpwd_mutex);
> -		rval = cpwd_ioctl(file, cmd, arg);
> -		mutex_unlock(&cpwd_mutex);
> -		break;
> -
> -	/* everything else is handled by the generic compat layer */
> -	default:
> -		break;
> -	}
> -
> -	return rval;
> -}
> -
>  static ssize_t cpwd_write(struct file *file, const char __user *buf,
>  			  size_t count, loff_t *ppos)
>  {
> @@ -520,7 +497,7 @@ static ssize_t cpwd_read(struct file *file, char __user *buffer,
>  static const struct file_operations cpwd_fops = {
>  	.owner =		THIS_MODULE,
>  	.unlocked_ioctl =	cpwd_ioctl,
> -	.compat_ioctl =		cpwd_compat_ioctl,
> +	.compat_ioctl =		compat_ptr_ioctl,
>  	.open =			cpwd_open,
>  	.write =		cpwd_write,
>  	.read =			cpwd_read,
Arnd Bergmann Oct. 8, 2019, 7:38 a.m. UTC | #3
On Tue, Oct 8, 2019 at 1:30 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Wed, Aug 14, 2019 at 10:42:32PM +0200, Arnd Bergmann wrote:
> > The cpwd_compat_ioctl() contains a bogus mutex that dates
> > back to a leftover BKL instance.
> >
> > Simplify the implementation by using the new compat_ptr_ioctl()
> > helper function that will do the right thing for all calls
> > here.
> >
> > Note that WIOCSTART/WIOCSTOP don't take any arguments, so
> > the compat_ptr() conversion is not needed here, but it also
> > doesn't hurt.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > Reviewed-by: Guenter Roeck <linux@roeck-us.net>
>
> This patch made it into the kernel, but the infrastructure didn't make it.
> Do we need to revert it ?

Sorry I had not realized that this patch got queued in the watchdog tree
and relied on the other patches. I ended up not sending the series after
a runtime regression in another driver, combined with the series not
having spent much time in linux-next before the merge window.

I've sent a fixup patch now that will make it do the right thing
regardless of my series, please apply that for v5.4.

        Arnd

Patch
diff mbox series

diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
index b973b31179df..9393be584e72 100644
--- a/drivers/watchdog/cpwd.c
+++ b/drivers/watchdog/cpwd.c
@@ -473,29 +473,6 @@  static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return 0;
 }
 
-static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
-			      unsigned long arg)
-{
-	int rval = -ENOIOCTLCMD;
-
-	switch (cmd) {
-	/* solaris ioctls are specific to this driver */
-	case WIOCSTART:
-	case WIOCSTOP:
-	case WIOCGSTAT:
-		mutex_lock(&cpwd_mutex);
-		rval = cpwd_ioctl(file, cmd, arg);
-		mutex_unlock(&cpwd_mutex);
-		break;
-
-	/* everything else is handled by the generic compat layer */
-	default:
-		break;
-	}
-
-	return rval;
-}
-
 static ssize_t cpwd_write(struct file *file, const char __user *buf,
 			  size_t count, loff_t *ppos)
 {
@@ -520,7 +497,7 @@  static ssize_t cpwd_read(struct file *file, char __user *buffer,
 static const struct file_operations cpwd_fops = {
 	.owner =		THIS_MODULE,
 	.unlocked_ioctl =	cpwd_ioctl,
-	.compat_ioctl =		cpwd_compat_ioctl,
+	.compat_ioctl =		compat_ptr_ioctl,
 	.open =			cpwd_open,
 	.write =		cpwd_write,
 	.read =			cpwd_read,