[PATCH v3 3/4] scsi: qla2xxx: always wait for qlt_sess_work_fn() from qlt_stop_phase1()

From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Nilesh Javali <njavali@marvell.com>,
	GR-QLogic-Storage-Upstream@marvell.com,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Subject: [PATCH v3 3/4] scsi: qla2xxx: always wait for qlt_sess_work_fn() from qlt_stop_phase1()
Date: Sat, 2 Jul 2022 14:00:20 +0900	[thread overview]
Message-ID: <9e454c72-5af2-5de3-db86-d27f699fa0c0@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <46629616-be04-9a53-b9d8-b2b947adf9d0@I-love.SAKURA.ne.jp>

Currently qlt_stop_phase1() may fail to call flush_scheduled_work(), for
list_empty() may return true as soon as qlt_sess_work_fn() called
list_del(). In order to close this race window, check list_empty() after
calling flush_scheduled_work().

If this patch causes problems, please check commit c4f135d643823a86
("workqueue: Wrap flush_workqueue() using a macro"). We are on the way to
remove all flush_scheduled_work() calls from the kernel.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
This patch is only compile tested.

 drivers/scsi/qla2xxx/qla_target.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index b170ebbd05b7..9013c162d4aa 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -1557,11 +1557,11 @@ int qlt_stop_phase1(struct qla_tgt *tgt)
 	ql_dbg(ql_dbg_tgt_mgt, vha, 0xf009,
 	    "Waiting for sess works (tgt %p)", tgt);
 	spin_lock_irqsave(&tgt->sess_work_lock, flags);
-	while (!list_empty(&tgt->sess_works_list)) {
+	do {
 		spin_unlock_irqrestore(&tgt->sess_work_lock, flags);
 		flush_scheduled_work();
 		spin_lock_irqsave(&tgt->sess_work_lock, flags);
-	}
+	} while (!list_empty(&tgt->sess_works_list));
 	spin_unlock_irqrestore(&tgt->sess_work_lock, flags);
 
 	ql_dbg(ql_dbg_tgt_mgt, vha, 0xf00a,
-- 
2.18.4

