mm: cma: fix incorrect type conversion for size during dma allocation

This was found during userspace fuzzing test when a large size dma cma
allocation is made by driver(like ion) through userspace.

  show_stack+0x10/0x1c
  dump_stack+0x74/0xc8
  kasan_report_error+0x2b0/0x408
  kasan_report+0x34/0x40
  __asan_storeN+0x15c/0x168
  memset+0x20/0x44
  __dma_alloc_coherent+0x114/0x18c

Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/cma.c b/mm/cma.c
index e7d1db5..4eb56ba 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -361,7 +361,7 @@
  * This function allocates part of contiguous memory on specific
  * contiguous memory area.
  */
-struct page *cma_alloc(struct cma *cma, unsigned int count, unsigned int align)
+struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
 {
 	unsigned long mask, offset, pfn, start = 0;
 	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
@@ -371,7 +371,7 @@
 	if (!cma || !cma->count)
 		return NULL;
 
-	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+	pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
 		 count, align);
 
 	if (!count)