[RFC PATCH 1/6] drm/gma500: use the common dumb-buffer size helper

[Gabriel Gama <operatingsystemsdepression@gmail.com>]

Use drm_mode_size_dumb() instead of unchecked size_t arithmetic when
calculating dumb-buffer pitch and size. Preserve 64-byte pitch alignment
and page-aligned allocations through the common DRM helper.

Signed-off-by: Gabriel Gama <operatingsystemsdepression@gmail.com>

---
 drivers/gpu/drm/gma500/gem.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c
index 2708e8c68..7250bf660 100644
--- a/drivers/gpu/drm/gma500/gem.c
+++ b/drivers/gpu/drm/gma500/gem.c
@@ -16,6 +16,7 @@
 #include <asm/set_memory.h>
 
 #include <drm/drm.h>
+#include <drm/drm_dumb_buffers.h>
 #include <drm/drm_print.h>
 #include <drm/drm_vma_manager.h>
 
@@ -200,21 +201,16 @@ psb_gem_create(struct drm_device *dev, u64 size, const char *name, bool stolen,
 int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
 			struct drm_mode_create_dumb *args)
 {
-	size_t pitch, size;
 	struct psb_gem_object *pobj;
 	struct drm_gem_object *obj;
 	u32 handle;
 	int ret;
 
-	pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
-	pitch = ALIGN(pitch, 64);
-
-	size = pitch * args->height;
-	size = roundup(size, PAGE_SIZE);
-	if (!size)
-		return -EINVAL;
+	ret = drm_mode_size_dumb(dev, args, 64, 0);
+	if (ret)
+		return ret;
 
-	pobj = psb_gem_create(dev, size, "gem", false, PAGE_SIZE);
+	pobj = psb_gem_create(dev, args->size, "gem", false, PAGE_SIZE);
 	if (IS_ERR(pobj))
 		return PTR_ERR(pobj);
 	obj = &pobj->base;
@@ -225,8 +221,6 @@ int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
 
 	drm_gem_object_put(obj);
 
-	args->pitch = pitch;
-	args->size = size;
 	args->handle = handle;
 
 	return 0;