aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJeff Mahoney <jeffm@suse.com>2006-06-26 00:27:25 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 09:58:35 -0700
commit10da4f795f965f22039aa2930b6f80964aad3ee5 (patch)
tree6f4bfd27cdcdad15b53df997476fae539383bf4a
parent7ec75f254742766eb729f1d1024a5b4e6692fc5f (diff)
downloadmrst-s0i3-test-10da4f795f965f22039aa2930b6f80964aad3ee5.tar.gz
mrst-s0i3-test-10da4f795f965f22039aa2930b6f80964aad3ee5.tar.xz
mrst-s0i3-test-10da4f795f965f22039aa2930b6f80964aad3ee5.zip
[PATCH] dm: add module ref counting
The reference counting on dm-mod is zero if no mapped devices are open. This is incorrect, and can lead to an oops if the module is unloaded while mapped devices exist. This patch claims a reference to the module whenever a device is created, and drops it again when the device is freed. Devices must be removed before dm-mod is unloaded. [akpm: too late for 2.6.17 - suitable for 2.6.17.x after it has settled] Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--drivers/md/dm.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a5cc4c8462f..29af584ae83 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -852,6 +852,9 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
return NULL;
}
+ if (!try_module_get(THIS_MODULE))
+ goto bad0;
+
/* get a minor number for the dev */
r = persistent ? specific_minor(md, minor) : next_free_minor(md, &minor);
if (r < 0)
@@ -918,6 +921,8 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
blk_cleanup_queue(md->queue);
free_minor(minor);
bad1:
+ module_put(THIS_MODULE);
+ bad0:
kfree(md);
return NULL;
}
@@ -941,6 +946,7 @@ static void free_dev(struct mapped_device *md)
put_disk(md->disk);
blk_cleanup_queue(md->queue);
+ module_put(THIS_MODULE);
kfree(md);
}