diff mbox

drm/i915: Fix kzalloc() smatch warnings in get_initial_plane_config()

Message ID 1421848254-586-1-git-send-email-damien.lespiau@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Lespiau, Damien Jan. 21, 2015, 1:50 p.m. UTC
Smatch doesn't like:

  struct drm_framebuffer *fb;
  fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);

and warns with:

  warn: struct type mismatch 'drm_framebuffer vs intel_framebuffer'

This implicit cast was correct as struct intel_framebuffer has struct
drm_framebuffer as its first member, but in case someone want to reorder
the fields for some reason, it's slightly safer to access the underlying
drm_framebuffer through intel_fb->base.

Also, having fewer static analysis warnings is a worthy goal.

Cc: kbuild@01.org
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

Comments

Daniel Vetter Jan. 21, 2015, 1:54 p.m. UTC | #1
On Wed, Jan 21, 2015 at 01:50:54PM +0000, Damien Lespiau wrote:
> Smatch doesn't like:
> 
>   struct drm_framebuffer *fb;
>   fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> 
> and warns with:
> 
>   warn: struct type mismatch 'drm_framebuffer vs intel_framebuffer'
> 
> This implicit cast was correct as struct intel_framebuffer has struct
> drm_framebuffer as its first member, but in case someone want to reorder
> the fields for some reason, it's slightly safer to access the underlying
> drm_framebuffer through intel_fb->base.
> 
> Also, having fewer static analysis warnings is a worthy goal.
> 
> Cc: kbuild@01.org
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_display.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 65fce56..01dc80b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6584,13 +6584,16 @@ i9xx_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(DSPCNTR(plane));
>  
>  	if (INTEL_INFO(dev)->gen >= 4)
> @@ -7613,13 +7616,16 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(PLANE_CTL(pipe, 0));
>  	if (val & PLANE_CTL_TILED_MASK)
>  		plane_config->tiling = I915_TILING_X;
> @@ -7706,13 +7712,16 @@ ironlake_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(DSPCNTR(pipe));
>  
>  	if (INTEL_INFO(dev)->gen >= 4)
> -- 
> 1.8.3.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Ville Syrjälä Jan. 21, 2015, 1:57 p.m. UTC | #2
On Wed, Jan 21, 2015 at 01:50:54PM +0000, Damien Lespiau wrote:
> Smatch doesn't like:
> 
>   struct drm_framebuffer *fb;
>   fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> 
> and warns with:
> 
>   warn: struct type mismatch 'drm_framebuffer vs intel_framebuffer'
> 
> This implicit cast was correct as struct intel_framebuffer has struct
> drm_framebuffer as its first member, but in case someone want to reorder
> the fields for some reason, it's slightly safer to access the underlying
> drm_framebuffer through intel_fb->base.
> 
> Also, having fewer static analysis warnings is a worthy goal.
> 
> Cc: kbuild@01.org
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 65fce56..01dc80b 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6584,13 +6584,16 @@ i9xx_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);

sizeof(*intel_fb) while at it?

> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(DSPCNTR(plane));
>  
>  	if (INTEL_INFO(dev)->gen >= 4)
> @@ -7613,13 +7616,16 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(PLANE_CTL(pipe, 0));
>  	if (val & PLANE_CTL_TILED_MASK)
>  		plane_config->tiling = I915_TILING_X;
> @@ -7706,13 +7712,16 @@ ironlake_get_initial_plane_config(struct intel_crtc *crtc,
>  	int fourcc, pixel_format;
>  	int aligned_height;
>  	struct drm_framebuffer *fb;
> +	struct intel_framebuffer *intel_fb;
>  
> -	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> -	if (!fb) {
> +	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
> +	if (!intel_fb) {
>  		DRM_DEBUG_KMS("failed to alloc fb\n");
>  		return;
>  	}
>  
> +	fb = &intel_fb->base;
> +
>  	val = I915_READ(DSPCNTR(pipe));
>  
>  	if (INTEL_INFO(dev)->gen >= 4)
> -- 
> 1.8.3.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 65fce56..01dc80b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6584,13 +6584,16 @@  i9xx_get_initial_plane_config(struct intel_crtc *crtc,
 	int fourcc, pixel_format;
 	int aligned_height;
 	struct drm_framebuffer *fb;
+	struct intel_framebuffer *intel_fb;
 
-	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
-	if (!fb) {
+	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
+	if (!intel_fb) {
 		DRM_DEBUG_KMS("failed to alloc fb\n");
 		return;
 	}
 
+	fb = &intel_fb->base;
+
 	val = I915_READ(DSPCNTR(plane));
 
 	if (INTEL_INFO(dev)->gen >= 4)
@@ -7613,13 +7616,16 @@  skylake_get_initial_plane_config(struct intel_crtc *crtc,
 	int fourcc, pixel_format;
 	int aligned_height;
 	struct drm_framebuffer *fb;
+	struct intel_framebuffer *intel_fb;
 
-	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
-	if (!fb) {
+	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
+	if (!intel_fb) {
 		DRM_DEBUG_KMS("failed to alloc fb\n");
 		return;
 	}
 
+	fb = &intel_fb->base;
+
 	val = I915_READ(PLANE_CTL(pipe, 0));
 	if (val & PLANE_CTL_TILED_MASK)
 		plane_config->tiling = I915_TILING_X;
@@ -7706,13 +7712,16 @@  ironlake_get_initial_plane_config(struct intel_crtc *crtc,
 	int fourcc, pixel_format;
 	int aligned_height;
 	struct drm_framebuffer *fb;
+	struct intel_framebuffer *intel_fb;
 
-	fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
-	if (!fb) {
+	intel_fb = kzalloc(sizeof(struct intel_framebuffer), GFP_KERNEL);
+	if (!intel_fb) {
 		DRM_DEBUG_KMS("failed to alloc fb\n");
 		return;
 	}
 
+	fb = &intel_fb->base;
+
 	val = I915_READ(DSPCNTR(pipe));
 
 	if (INTEL_INFO(dev)->gen >= 4)