block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

In blk_stack_limits(), we check that the t->chunk_sectors value is a
multiple of the t->physical_block_size value.

However, by finding the chunk_sectors value in bytes, we may overflow
the unsigned int which holds chunk_sectors, so change the check to be
based on sectors.

Signed-off-by: John Garry <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>

Author: johnpgarry

block/blk-settings.c

@@ -779,7 +779,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	}
 
 	/* chunk_sectors a multiple of the physical block size? */
-	if ((t->chunk_sectors << 9) & (t->physical_block_size - 1)) {
+	if (t->chunk_sectors % (t->physical_block_size >> SECTOR_SHIFT)) {
 		t->chunk_sectors = 0;
 		t->flags |= BLK_FLAG_MISALIGNED;
 		ret = -1;