[PATCH] drm/vkms: Suppress context imbalance sparse warning

[PATCH] drm/vkms: Suppress context imbalance sparse warning

[Louis Chauvet]

The functions `vkms_crtc_atomic_begin` and `vkms_crtc_atomic_flush` are
responsible for locking and unlocking a mutex, respectively. Add the
`__acquires` and `__releases` annotations to these functions to prevent
the associated sparse warning about context imbalance.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_crtc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 40b4d084e3ceef9e1e24b7338efdd9253afee8d6..2ad164b518fb93f5b6b86948116ff7ed97770b60 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -232,6 +232,7 @@ static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
 
 static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
 				   struct drm_atomic_state *state)
+	__acquires(&vkms_output->lock)
 {
 	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
 
@@ -243,6 +244,7 @@ static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
 
 static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
 				   struct drm_atomic_state *state)
+	__releases(&vkms_output->lock)
 {
 	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
 

---
base-commit: d2194256049910d286cd6c308c2689df521d8842
change-id: 20240912-vkms-warnings-e0e331bc5e6d

Best regards,
-- 
Louis Chauvet <louis.chauvet@bootlin.com>

[PATCH] drm/vkms: Suppress context imbalance sparse warning

[José Expósito]

Hi Louis,

> The functions `vkms_crtc_atomic_begin` and `vkms_crtc_atomic_flush` are
> responsible for locking and unlocking a mutex, respectively. Add the
> `__acquires` and `__releases` annotations to these functions to prevent
> the associated sparse warning about context imbalance.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

Thanks for fixing this warning. Tested it and I can confirm that these
warnings are fixed now:

  drivers/gpu/drm/vkms/vkms_crtc.c:233:13: warning: context imbalance in 'vkms_crtc_atomic_begin' - wrong count at exit
  drivers/gpu/drm/vkms/vkms_crtc.c:262:39: warning: context imbalance in 'vkms_crtc_atomic_flush' - unexpected unlock

Feel free to add:
Reviewed-by: José Expósito <jose.exposito89@gmail.com>

> ---
>  drivers/gpu/drm/vkms/vkms_crtc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> 
> ---
> base-commit: d2194256049910d286cd6c308c2689df521d8842
> change-id: 20240912-vkms-warnings-e0e331bc5e6d
> 
> Best regards,
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index 40b4d084e3ceef9e1e24b7338efdd9253afee8d6..2ad164b518fb93f5b6b86948116ff7ed97770b60 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -232,6 +232,7 @@ static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
>  
>  static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
>  				   struct drm_atomic_state *state)
> +	__acquires(&vkms_output->lock)
>  {
>  	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
>  
> @@ -243,6 +244,7 @@ static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
>  
>  static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
>  				   struct drm_atomic_state *state)
> +	__releases(&vkms_output->lock)
>  {
>  	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
>  
> 

Re: [PATCH] drm/vkms: Suppress context imbalance sparse warning

[Maíra Canal]

Hi Louis,

On 9/12/24 12:25, Louis Chauvet wrote:
> The functions `vkms_crtc_atomic_begin` and `vkms_crtc_atomic_flush` are
> responsible for locking and unlocking a mutex, respectively. Add the
> `__acquires` and `__releases` annotations to these functions to prevent
> the associated sparse warning about context imbalance.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

When I was applying this patch, I got the following warning:

137f51649b04 (HEAD -> drm-misc-next) drm/vkms: Suppress context 
imbalance sparse warning
-:4: WARNING:EMAIL_SUBJECT: A patch subject line should describe the 
change not the tool that found it
#4:
Subject: [PATCH] drm/vkms: Suppress context imbalance sparse warning

total: 0 errors, 1 warnings, 0 checks, 14 lines checked

Therefore, before pushing the patch, I changed the commit title to
"drm/vkms: Suppress context imbalance detected by sparse warning". Hope
you don't mind.

Applied to misc/kernel.git (drm-misc-next).

Best Regards,
- Maíra

> ---
>   drivers/gpu/drm/vkms/vkms_crtc.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
> index 40b4d084e3ceef9e1e24b7338efdd9253afee8d6..2ad164b518fb93f5b6b86948116ff7ed97770b60 100644
> --- a/drivers/gpu/drm/vkms/vkms_crtc.c
> +++ b/drivers/gpu/drm/vkms/vkms_crtc.c
> @@ -232,6 +232,7 @@ static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
>   
>   static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
>   				   struct drm_atomic_state *state)
> +	__acquires(&vkms_output->lock)
>   {
>   	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
>   
> @@ -243,6 +244,7 @@ static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
>   
>   static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
>   				   struct drm_atomic_state *state)
> +	__releases(&vkms_output->lock)
>   {
>   	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
>   
> 
> ---
> base-commit: d2194256049910d286cd6c308c2689df521d8842
> change-id: 20240912-vkms-warnings-e0e331bc5e6d
> 
> Best regards,