From: Mike Snitzer Date: Sat, 25 Nov 2017 05:27:26 +0000 (-0500) Subject: dm table: fix regression from improper dm_dev_internal.count refcount_t conversion X-Git-Tag: v4.15-rc4~17^2~3 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=afc567a4977b2d798e05153dd131a3c8d4758c0c;p=linux.git dm table: fix regression from improper dm_dev_internal.count refcount_t conversion Multiple refcounts are needed if the device was already added. The micro-optimization of setting the refcount to 1 on first added (rather than fall thru to a common refcount_inc) lost sight of the fact that the refcount_inc is also needed for the case when the device already exists and the mode need not be upgraded. Fixes: 2a0b4682e0 ("dm: convert dm_dev_internal.count from atomic_t to refcount_t") Reported-by: Zdenek Kabelac Signed-off-by: Mike Snitzer --- diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 88130b5d95f9..aaffd0c0ee9a 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -453,14 +453,15 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, refcount_set(&dd->count, 1); list_add(&dd->list, &t->devices); + goto out; } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) { r = upgrade_mode(dd, mode, t->md); if (r) return r; - refcount_inc(&dd->count); } - + refcount_inc(&dd->count); +out: *result = dd->dm_dev; return 0; }