dm-stripe: fix a possible integer overflow

There's a possible integer overflow in stripe_io_hints if we have too
large chunk size. Test if the overflow happened, and if it did, don't set
limits->io_min and limits->io_opt;

Signed-off-by: Mikulas Patocka <[e-mail]>
Reviewed-by: John Garry <[e-mail]>
Suggested-by: Dongsheng Yang <[e-mail]>
Cc: [e-mail]

drivers/md/dm-stripe.c

···
 			    struct queue_limits *limits)
 {
 	struct stripe_c *sc = ti->private;
-	unsigned int chunk_size = sc->chunk_size << SECTOR_SHIFT;
+	unsigned int io_min, io_opt;
 
 	limits->chunk_sectors = sc->chunk_size;
-	limits->io_min = chunk_size;
-	limits->io_opt = chunk_size * sc->stripes;
+
+	if (!check_shl_overflow(sc->chunk_size, SECTOR_SHIFT, &io_min) &&
+	    !check_mul_overflow(io_min, sc->stripes, &io_opt)) {
+		limits->io_min = io_min;
+		limits->io_opt = io_opt;
+	}
 }
 
 static struct target_type stripe_target = {