diff mbox series

[v2] gpiolib: Switch to use compat_need_64bit_alignment_fixup() helper

Message ID 20201008134105.51387-1-andriy.shevchenko@linux.intel.com
State Superseded
Headers show
Series [v2] gpiolib: Switch to use compat_need_64bit_alignment_fixup() helper | expand

Commit Message

Andy Shevchenko Oct. 8, 2020, 1:41 p.m. UTC
The new compat_need_64bit_alignment_fixup() helper allows to avoid
ugly ifdeffery in IOCTL compatible code. Use it in GPIO cdev code.

Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")
Depends-on: cc7886d25bca ("compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: removed lineevent_get_size() completely, fixed typo in commit message
 drivers/gpio/gpiolib-cdev.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

Comments

Kent Gibson Oct. 12, 2020, 4:20 a.m. UTC | #1
On Thu, Oct 08, 2020 at 04:41:05PM +0300, Andy Shevchenko wrote:
> The new compat_need_64bit_alignment_fixup() helper allows to avoid
> ugly ifdeffery in IOCTL compatible code. Use it in GPIO cdev code.
> 
> Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")
> Depends-on: cc7886d25bca ("compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>")

Where can I find these?

Cheers,
Kent.
Andy Shevchenko Oct. 12, 2020, 10:03 a.m. UTC | #2
On Mon, Oct 12, 2020 at 12:20:10PM +0800, Kent Gibson wrote:
> On Thu, Oct 08, 2020 at 04:41:05PM +0300, Andy Shevchenko wrote:
> > The new compat_need_64bit_alignment_fixup() helper allows to avoid
> > ugly ifdeffery in IOCTL compatible code. Use it in GPIO cdev code.
> > 
> > Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")
> > Depends-on: cc7886d25bca ("compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>")
> 
> Where can I find these?

Soon in Linux upstream, but currently in Al Viro's tree: https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/log/?h=work.quota-compat
Kent Gibson Oct. 12, 2020, 1:07 p.m. UTC | #3
On Thu, Oct 08, 2020 at 04:41:05PM +0300, Andy Shevchenko wrote:
> The new compat_need_64bit_alignment_fixup() helper allows to avoid
> ugly ifdeffery in IOCTL compatible code. Use it in GPIO cdev code.
> 

I'd re-arrange that checkin comment to

"Use the new compat_need_64bit_alignment_fixup() helper to avoid
ugly ifdeffery in IOCTL compatibility code."

but otherwise all good.

+1 on the deuglification, and it still works too.

Tested-by: Kent Gibson <warthog618@gmail.com>

> Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")
> Depends-on: cc7886d25bca ("compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> v2: removed lineevent_get_size() completely, fixed typo in commit message
>  drivers/gpio/gpiolib-cdev.c | 24 ++++++++----------------
>  1 file changed, 8 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index e9faeaf65d14..192721f829a3 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -1479,21 +1479,10 @@ static __poll_t lineevent_poll(struct file *file,
>  	return events;
>  }
>  
> -static ssize_t lineevent_get_size(void)
> -{
> -#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
> -	/* i386 has no padding after 'id' */
> -	if (in_ia32_syscall()) {
> -		struct compat_gpioeevent_data {
> -			compat_u64	timestamp;
> -			u32		id;
> -		};
> -
> -		return sizeof(struct compat_gpioeevent_data);
> -	}
> -#endif
> -	return sizeof(struct gpioevent_data);
> -}
> +struct compat_gpioeevent_data {
> +	compat_u64	timestamp;
> +	u32		id;
> +};
>  
>  static ssize_t lineevent_read(struct file *file,
>  			      char __user *buf,
> @@ -1515,7 +1504,10 @@ static ssize_t lineevent_read(struct file *file,
>  	 * actual sizeof() and pass this as an argument to copy_to_user() to
>  	 * drop unneeded bytes from the output.
>  	 */
> -	ge_size = lineevent_get_size();
> +	if (compat_need_64bit_alignment_fixup())
> +		ge_size = sizeof(struct compat_gpioeevent_data);
> +	else
> +		ge_size = sizeof(struct gpioevent_data);
>  	if (count < ge_size)
>  		return -EINVAL;
>  
> -- 
> 2.28.0
>
Andy Shevchenko Oct. 12, 2020, 2 p.m. UTC | #4
On Mon, Oct 12, 2020 at 09:07:41PM +0800, Kent Gibson wrote:
> On Thu, Oct 08, 2020 at 04:41:05PM +0300, Andy Shevchenko wrote:
> > The new compat_need_64bit_alignment_fixup() helper allows to avoid
> > ugly ifdeffery in IOCTL compatible code. Use it in GPIO cdev code.

> I'd re-arrange that checkin comment to
> 
> "Use the new compat_need_64bit_alignment_fixup() helper to avoid
> ugly ifdeffery in IOCTL compatibility code."

OK!

> but otherwise all good.
> 
> +1 on the deuglification, and it still works too.
> 
> Tested-by: Kent Gibson <warthog618@gmail.com>

Thanks.

> > Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")

> > Depends-on: cc7886d25bca ("compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>")

I'll also drop this one, since former is dependent on latter.
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index e9faeaf65d14..192721f829a3 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1479,21 +1479,10 @@  static __poll_t lineevent_poll(struct file *file,
 	return events;
 }
 
-static ssize_t lineevent_get_size(void)
-{
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
-	/* i386 has no padding after 'id' */
-	if (in_ia32_syscall()) {
-		struct compat_gpioeevent_data {
-			compat_u64	timestamp;
-			u32		id;
-		};
-
-		return sizeof(struct compat_gpioeevent_data);
-	}
-#endif
-	return sizeof(struct gpioevent_data);
-}
+struct compat_gpioeevent_data {
+	compat_u64	timestamp;
+	u32		id;
+};
 
 static ssize_t lineevent_read(struct file *file,
 			      char __user *buf,
@@ -1515,7 +1504,10 @@  static ssize_t lineevent_read(struct file *file,
 	 * actual sizeof() and pass this as an argument to copy_to_user() to
 	 * drop unneeded bytes from the output.
 	 */
-	ge_size = lineevent_get_size();
+	if (compat_need_64bit_alignment_fixup())
+		ge_size = sizeof(struct compat_gpioeevent_data);
+	else
+		ge_size = sizeof(struct gpioevent_data);
 	if (count < ge_size)
 		return -EINVAL;