[PATCH 2/5] video: Add missing annotation for cyber2000fb_enable_ddc() and cyber2000fb_disable_ddc()

[PATCH 2/5] video: Add missing annotation for cyber2000fb_enable_ddc() and cyber2000fb_disable_ddc()

[Jules Irenge]

Sparse reports warnings at cyber2000fb_enable_ddc()
	and cyber2000fb_disable_ddc()

warning: context imbalance in cyber2000fb_enable_ddc()
	- wrong count at exit

warning: context imbalance in cyber2000fb_disable_ddc()
	- unexpected unlock

The root cause is the missing annotation at cyber2000fb_enable_ddc()
	and cyber2000fb_disable_ddc()

Add the missing __acquires(&cfb->reg_b0_lock) annotation
Add the missing __releases(&cfb->reg_b0_lock) annotation

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
---
 drivers/video/fbdev/cyber2000fb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/video/fbdev/cyber2000fb.c b/drivers/video/fbdev/cyber2000fb.c
index 460826a7ad55..513f58f28b0f 100644
--- a/drivers/video/fbdev/cyber2000fb.c
+++ b/drivers/video/fbdev/cyber2000fb.c
@@ -1160,12 +1160,14 @@ EXPORT_SYMBOL(cyber2000fb_detach);
 #define DDC_SDA_IN	(1 << 6)
 
 static void cyber2000fb_enable_ddc(struct cfb_info *cfb)
+	__acquires(&cfb->reg_b0_lock)
 {
 	spin_lock(&cfb->reg_b0_lock);
 	cyber2000fb_writew(0x1bf, 0x3ce, cfb);
 }
 
 static void cyber2000fb_disable_ddc(struct cfb_info *cfb)
+	__releases(&cfb->reg_b0_lock)
 {
 	cyber2000fb_writew(0x0bf, 0x3ce, cfb);
 	spin_unlock(&cfb->reg_b0_lock);
-- 
2.24.1


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Re: [PATCH 2/5] video: Add missing annotation for cyber2000fb_enable_ddc() and cyber2000fb_disable_ddc()

[Sam Ravnborg]

Hi Jules.

On Fri, Apr 03, 2020 at 05:05:02PM +0100, Jules Irenge wrote:
> Sparse reports warnings at cyber2000fb_enable_ddc()
> 	and cyber2000fb_disable_ddc()
> 
> warning: context imbalance in cyber2000fb_enable_ddc()
> 	- wrong count at exit
> 
> warning: context imbalance in cyber2000fb_disable_ddc()
> 	- unexpected unlock
> 
> The root cause is the missing annotation at cyber2000fb_enable_ddc()
> 	and cyber2000fb_disable_ddc()
> 
> Add the missing __acquires(&cfb->reg_b0_lock) annotation
> Add the missing __releases(&cfb->reg_b0_lock) annotation
> 
> Signed-off-by: Jules Irenge <jbi.octave@gmail.com>

Thanks, added to drm-misc-next, so the patch will hit the kernel
when the merge windows opens the next time.

Was this the only locking relevant warning in fbdev?
I would expect a few more.

	Sam

> ---
>  drivers/video/fbdev/cyber2000fb.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/video/fbdev/cyber2000fb.c b/drivers/video/fbdev/cyber2000fb.c
> index 460826a7ad55..513f58f28b0f 100644
> --- a/drivers/video/fbdev/cyber2000fb.c
> +++ b/drivers/video/fbdev/cyber2000fb.c
> @@ -1160,12 +1160,14 @@ EXPORT_SYMBOL(cyber2000fb_detach);
>  #define DDC_SDA_IN	(1 << 6)
>  
>  static void cyber2000fb_enable_ddc(struct cfb_info *cfb)
> +	__acquires(&cfb->reg_b0_lock)
>  {
>  	spin_lock(&cfb->reg_b0_lock);
>  	cyber2000fb_writew(0x1bf, 0x3ce, cfb);
>  }
>  
>  static void cyber2000fb_disable_ddc(struct cfb_info *cfb)
> +	__releases(&cfb->reg_b0_lock)
>  {
>  	cyber2000fb_writew(0x0bf, 0x3ce, cfb);
>  	spin_unlock(&cfb->reg_b0_lock);
> -- 
> 2.24.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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