Patchwork [PATCHv3,8/9] mtd: Raise limit on block device minor numbers

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Submitter Ben Hutchings
Date Jan. 29, 2010, 8:59 p.m.
Message ID <1264798793.2785.40.camel@achroite.uk.solarflarecom.com>
Download mbox | patch
Permalink /patch/44031/
State Accepted
Commit 4d3a8534bdbcf4843fc8ad05c9a81a964fc65237
Headers show

Comments

Ben Hutchings - Jan. 29, 2010, 8:59 p.m.
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 <bhutchings@solarflare.com>
---
 drivers/mtd/mtd_blkdevs.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 85a52b3..2f8c202 100644
--- 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: