[PATCH 6.1.y] dm-verity: avoid double increment of &use_bh_wq_enabled

[Sasha Levin <sashal@kernel.org>]

From: Mikulas Patocka <mpatocka@redhat.com>

[ Upstream commit 72e9ec2fe32b00994f41719cf77423fca67d48b2 ]

verity_parse_opt_args is called twice, first with the only_modifier_opts,
first with only_modifier_opts == true and then with only_modifier_opts ==
false. Thus, the static branch &use_bh_wq_enabled was incremented twice
and the destructor verity_dtr would only decrement it once.

Fix tihs bug by only incrementing it on the first call, on the second
call, when v->use_bh_wq is true, do nothing.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Cc: stable@vger.kernel.org
Fixes: df326e7a0699 ("dm verity: allow optional args to alter primary args handling")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/dm-verity-target.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 53150024d2dd4e..54f9adaf5fcdc6 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1151,6 +1151,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_TASKLET_VERIFY)) {
+			if (v->use_tasklet)
+				continue;
 			v->use_tasklet = true;
 			static_branch_inc(&use_tasklet_enabled);
 			continue;
-- 
2.53.0