mtd: Raise limit on block device minor numbers

add_mtd_blktrans_dev() imposes a maximum of 257 devices per block translator. This was presumably meant to prevent overflow back in the days of 8-bit minor numbers. Instead, check against MINORMASK and the limits of the partition naming scheme. Signed-off-by: Ben Hutchings <[email protected]> Signed-off-by: Artem Bityutskiy <[email protected]> Signed-off-by: David Woodhouse <[email protected]>
goeke · Feb 25, 2010 · 4d3a853 · 4d3a853
1 parent b520e41
commit 4d3a853
Showing 1 changed file with 5 additions and 2 deletions.
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
@@ -242,9 +242,12 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	if (new->devnum == -1)
 		new->devnum = last_devnum+1;
 
-	if ((new->devnum << tr->part_bits) > 256) {
+	/* Check that the device and any partitions will get valid
+	 * minor numbers and that the disk naming code below can cope
+	 * with this number. */
+	if (new->devnum > (MINORMASK >> tr->part_bits) ||
+	    (tr->part_bits && new->devnum >= 27 * 26))
 		return -EBUSY;
-	}
 
 	list_add_tail(&new->list, &tr->devs);
  added: