Re: [PATCH 2/5] drm/i915: Use kcalloc more

Jani Nikula
2013-09-19T10:36:03Z

On Thu, 19 Sep 2013, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> No buffer overflows here, but better safe than sorry.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 5 +++--
> drivers/gpu/drm/i915/i915_gem_gtt.c | 8 ++++----
> drivers/gpu/drm/i915/i915_gem_tiling.c | 6 +++---
> drivers/gpu/drm/i915/i915_gpu_error.c | 4 ++--
> drivers/gpu/drm/i915/intel_display.c | 2 +-
> 5 files changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index ee93357..a733118 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/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;
> @@ -1302,7 +1303,7 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data,
> return -EINVAL;
> }
>
> - exec2_list = kmalloc(sizeof(*exec2_list)*args->buffer_count,
> + exec2_list = kcalloc(args->buffer_count, sizeof(*exec2_list),
> GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
> if (exec2_list == NULL)
> exec2_list = drm_malloc_ab(sizeof(*exec2_list),
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 212f6d8..dafbdb7 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -336,8 +336,8 @@ 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,
> - GFP_KERNEL);
> + ppgtt->pt_pages = kcalloc(ppgtt->num_pd_entries, sizeof(struct page *),
> + GFP_KERNEL | __GFP_ZERO);

kcalloc implies __GFP_ZERO, specifying it is redundant. Ditto
below. This also means this patch does a bunch of zeroing that's
strictly not necessary.

> if (!ppgtt->pt_pages)
> return -ENOMEM;
>
> @@ -347,8 +347,8 @@ 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,
> - GFP_KERNEL);
> + ppgtt->pt_dma_addr = kcalloc(ppgtt->num_pd_entries, sizeof(dma_addr_t),
> + GFP_KERNEL | __GFP_ZERO);
> if (!ppgtt->pt_dma_addr)
> goto err_pt_alloc;
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
> index 032e9ef..ac9ebe9 100644
> --- a/drivers/gpu/drm/i915/i915_gem_tiling.c
> +++ b/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");
> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
> index c38d575..763283e 100644
> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
> @@ -791,7 +791,7 @@ 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),

Crash boom bang.

BR,
Jani.

> GFP_ATOMIC);
> if (error->ring[i].requests == NULL) {
> error->ring[i].num_requests = 0;
> @@ -833,7 +833,7 @@ 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];
> }
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index fe8db37..6b8a107 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9031,7 +9031,7 @@ 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;
> --
> 1.8.4.rc3
>
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--
Jani Nikula, Intel Open Source Technology Center