[PATCH 5.1 104/122] dm init: fix max devices/targets checks

Greg Kroah-Hartman
2019-05-23T19:31:09Z

From: Helen Koike <helen.koike@collabora.com>

commit 8e890c1ab1b1e0f765cd8da82c4dee011698a5e8 upstream.

dm-init should allow up to DM_MAX_{DEVICES,TARGETS} for devices/targets,
and not DM_MAX_{DEVICES,TARGETS} - 1.

Fix the checks and also fix the error message when the number of devices
is surpassed.

Fixes: 6bbc923dfcf57d ("dm: add support to directly boot to a mapped device")
Cc: stable@vger.kernel.org
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-init.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/md/dm-init.c
+++ b/drivers/md/dm-init.c
@@ -160,7 +160,7 @@ static int __init dm_parse_table(struct

while (table_entry) {
DMDEBUG("parsing table \"%s\"", str);
- if (++dev->dmi.target_count >= DM_MAX_TARGETS) {
+ if (++dev->dmi.target_count > DM_MAX_TARGETS) {
DMERR("too many targets %u > %d",
dev->dmi.target_count, DM_MAX_TARGETS);
return -EINVAL;
@@ -242,9 +242,9 @@ static int __init dm_parse_devices(struc
return -ENOMEM;
list_add_tail(&dev->list, devices);

- if (++ndev >= DM_MAX_DEVICES) {
- DMERR("too many targets %u > %d",
- dev->dmi.target_count, DM_MAX_TARGETS);
+ if (++ndev > DM_MAX_DEVICES) {
+ DMERR("too many devices %lu > %d",
+ ndev, DM_MAX_DEVICES);
return -EINVAL;
}