The advantage of kcalloc is, that will prevent integer overflows which could result from the multiplication of number of elements and size and it is also a bit nicer to read.
The semantic patch that makes this change is available in https://lkml.org/lkml/2011/11/25/107 Signed-off-by: Thomas Meyer <thomas at m3y3r.de> --- diff -u -p a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c --- a/drivers/gpu/drm/drm_bufs.c 2011-11-13 11:07:23.536775743 +0100 +++ b/drivers/gpu/drm/drm_bufs.c 2011-11-28 19:50:05.523467782 +0100 @@ -679,7 +679,7 @@ int drm_addbufs_agp(struct drm_device * return -EINVAL; } - entry->buflist = kzalloc(count * sizeof(*entry->buflist), GFP_KERNEL); + entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL); if (!entry->buflist) { mutex_unlock(&dev->struct_mutex); atomic_dec(&dev->buf_alloc); @@ -831,14 +831,14 @@ int drm_addbufs_pci(struct drm_device * return -EINVAL; } - entry->buflist = kzalloc(count * sizeof(*entry->buflist), GFP_KERNEL); + entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL); if (!entry->buflist) { mutex_unlock(&dev->struct_mutex); atomic_dec(&dev->buf_alloc); return -ENOMEM; } - entry->seglist = kzalloc(count * sizeof(*entry->seglist), GFP_KERNEL); + entry->seglist = kcalloc(count, sizeof(*entry->seglist), GFP_KERNEL); if (!entry->seglist) { kfree(entry->buflist); mutex_unlock(&dev->struct_mutex); @@ -1044,8 +1044,7 @@ static int drm_addbufs_sg(struct drm_dev return -EINVAL; } - entry->buflist = kzalloc(count * sizeof(*entry->buflist), - GFP_KERNEL); + entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL); if (!entry->buflist) { mutex_unlock(&dev->struct_mutex); atomic_dec(&dev->buf_alloc); @@ -1202,8 +1201,7 @@ static int drm_addbufs_fb(struct drm_dev return -EINVAL; } - entry->buflist = kzalloc(count * sizeof(*entry->buflist), - GFP_KERNEL); + entry->buflist = kcalloc(count, sizeof(*entry->buflist), GFP_KERNEL); if (!entry->buflist) { mutex_unlock(&dev->struct_mutex); atomic_dec(&dev->buf_alloc); diff -u -p a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c --- a/drivers/gpu/drm/drm_crtc.c 2011-11-28 19:36:47.383431617 +0100 +++ b/drivers/gpu/drm/drm_crtc.c 2011-11-28 19:50:03.813436083 +0100 @@ -1877,7 +1877,7 @@ int drm_mode_dirtyfb_ioctl(struct drm_de ret = -EINVAL; goto out_err1; } - clips = kzalloc(num_clips * sizeof(*clips), GFP_KERNEL); + clips = kcalloc(num_clips, sizeof(*clips), GFP_KERNEL); if (!clips) { ret = -ENOMEM; goto out_err1;
