[patch] drm/radeon: check for allocation failure in radeon_ring_backup()

[Dan Carpenter]

Static checkers complain if this we don't check for allocation failure.
Also we can use the new kmalloc_array() function here as a cleanup.

Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

diff --git a/drivers/gpu/drm/radeon/radeon_ring.c 
b/drivers/gpu/drm/radeon/radeon_ring.c
index 75cbe46..5a0ef24 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -402,7 +402,11 @@ unsigned radeon_ring_backup(struct radeon_device *rdev, 
struct radeon_ring *ring
        }

        /* and then save the content of the ring */
-       *data = kmalloc(size * 4, GFP_KERNEL);
+       *data = kmalloc_array(size, sizeof(uint32_t), GFP_KERNEL);
+       if (!*data) {
+               mutex_unlock(&rdev->ring_lock);
+               return 0;
+       }
        for (i = 0; i < size; ++i) {
                (*data)[i] = ring->ring[ptr++];
                ptr &= ring->ptr_mask;