dma-buf: use krealloc_array()

Use the helper that checks for overflows internally instead of manually
calculating the size of the new array.

Link: https://lkml.kernel.org/r/20201109110654.12547-10-brgl@bgdev.plSigned-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: David Rientjes <rientjes@google.com>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/dma-buf/sync_file.c

@@ -270,8 +270,7 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
 		fences[i++] = dma_fence_get(a_fences[0]);
 
 	if (num_fences > i) {
-		nfences = krealloc(fences, i * sizeof(*fences),
-				  GFP_KERNEL);
+		nfences = krealloc_array(fences, i, sizeof(*fences), GFP_KERNEL);
 		if (!nfences)
 			goto err;