drm/i915: Use kcalloc more

No buffer overflows here, but better safe than sorry.

v2:
- Fixup the sizeof conversion, I've missed the pointer deref (Jani).
- Drop the redundant GFP_ZERO, kcalloc alreads memsets (Jani).
- Use kmalloc_array for the execbuf fastpath to avoid the memset
  (Chris). I've opted to leave all other conversions as-is since they
  aren't in a fastpath and dealing with cleared memory instead of
  random garbage is just generally nicer.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Drop the contentious kmalloc_array hunk in execbuf.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -1047,7 +1047,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 			return -EINVAL;
 		}
 
-		cliprects = kmalloc(args->num_cliprects * sizeof(*cliprects),
+		cliprects = kcalloc(args->num_cliprects,
+				    sizeof(*cliprects),
 				    GFP_KERNEL);
 		if (cliprects == NULL) {
 			ret = -ENOMEM;

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -336,7 +336,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 	ppgtt->base.insert_entries = gen6_ppgtt_insert_entries;
 	ppgtt->base.cleanup = gen6_ppgtt_cleanup;
 	ppgtt->base.scratch = dev_priv->gtt.base.scratch;
-	ppgtt->pt_pages = kzalloc(sizeof(struct page *)*ppgtt->num_pd_entries,
+	ppgtt->pt_pages = kcalloc(ppgtt->num_pd_entries, sizeof(struct page *),
 				  GFP_KERNEL);
 	if (!ppgtt->pt_pages)
 		return -ENOMEM;
@@ -347,7 +347,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
 			goto err_pt_alloc;
 	}
 
-	ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t) *ppgtt->num_pd_entries,
+	ppgtt->pt_dma_addr = kcalloc(ppgtt->num_pd_entries, sizeof(dma_addr_t),
 				     GFP_KERNEL);
 	if (!ppgtt->pt_dma_addr)
 		goto err_pt_alloc;

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -393,7 +393,7 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
 	/* Try to preallocate memory required to save swizzling on put-pages */
 	if (i915_gem_object_needs_bit17_swizzle(obj)) {
 		if (obj->bit_17 == NULL) {
-			obj->bit_17 = kmalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT) *
+			obj->bit_17 = kcalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT),
 					      sizeof(long), GFP_KERNEL);
 		}
 	} else {
@@ -504,8 +504,8 @@ i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
 	int i;
 
 	if (obj->bit_17 == NULL) {
-		obj->bit_17 = kmalloc(BITS_TO_LONGS(page_count) *
-					   sizeof(long), GFP_KERNEL);
+		obj->bit_17 = kcalloc(BITS_TO_LONGS(page_count),
+				      sizeof(long), GFP_KERNEL);
 		if (obj->bit_17 == NULL) {
 			DRM_ERROR("Failed to allocate memory for bit 17 "
 				  "record\n");

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -793,7 +793,7 @@ static void i915_gem_record_rings(struct drm_device *dev,
 
 		error->ring[i].num_requests = count;
 		error->ring[i].requests =
-			kmalloc(count*sizeof(struct drm_i915_error_request),
+			kcalloc(count, sizeof(*error->ring[i].requests),
 				GFP_ATOMIC);
 		if (error->ring[i].requests == NULL) {
 			error->ring[i].num_requests = 0;
@@ -835,7 +835,7 @@ static void i915_gem_capture_vm(struct drm_i915_private *dev_priv,
 	error->pinned_bo_count[ndx] = i - error->active_bo_count[ndx];
 
 	if (i) {
-		active_bo = kmalloc(sizeof(*active_bo)*i, GFP_ATOMIC);
+		active_bo = kcalloc(i, sizeof(*active_bo), GFP_ATOMIC);
 		if (active_bo)
 			pinned_bo = active_bo + error->active_bo_count[ndx];
 	}

drivers/gpu/drm/i915/intel_display.c

@@ -9052,7 +9052,7 @@ static int __intel_set_mode(struct drm_crtc *crtc,
 	unsigned disable_pipes, prepare_pipes, modeset_pipes;
 	int ret = 0;
 
-	saved_mode = kmalloc(2 * sizeof(*saved_mode), GFP_KERNEL);
+	saved_mode = kcalloc(2, sizeof(*saved_mode), GFP_KERNEL);
 	if (!saved_mode)
 		return -ENOMEM;
 	saved_hwmode = saved_mode + 1;