netdev - [PATCH net-next 1/3] qed: Replace wq_active Boolean with an atomic QED_SLOWPATH

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Date:   Tue, 24 Mar 2020 16:13:46 +0200
From:   Yuval Basson <ybason@...vell.com>
To:     <davem@...emloft.net>, <netdev@...r.kernel.org>
CC:     Yuval Basson <ybason@...vell.com>,
        Denis Bolotin <dbolotin@...vell.com>
Subject: [PATCH net-next 1/3] qed: Replace wq_active Boolean with an atomic QED_SLOWPATH_ACTIVE flag

The atomic opertaion might prevent a potential race condition.

Signed-off-by: Yuval Basson <ybason@...vell.com>
Signed-off-by: Denis Bolotin <dbolotin@...vell.com>
---
 drivers/net/ethernet/qlogic/qed/qed.h      | 2 +-
 drivers/net/ethernet/qlogic/qed/qed_main.c | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed.h b/drivers/net/ethernet/qlogic/qed/qed.h
index fa41bf0..ca866c2 100644
--- a/drivers/net/ethernet/qlogic/qed/qed.h
+++ b/drivers/net/ethernet/qlogic/qed/qed.h
@@ -565,6 +565,7 @@ struct qed_simd_fp_handler {
 enum qed_slowpath_wq_flag {
 	QED_SLOWPATH_MFW_TLV_REQ,
 	QED_SLOWPATH_PERIODIC_DB_REC,
+	QED_SLOWPATH_ACTIVE,
 };
 
 struct qed_hwfn {
@@ -700,7 +701,6 @@ struct qed_hwfn {
 	unsigned long iov_task_flags;
 #endif
 	struct z_stream_s *stream;
-	bool slowpath_wq_active;
 	struct workqueue_struct *slowpath_wq;
 	struct delayed_work slowpath_task;
 	unsigned long slowpath_task_flags;
diff --git a/drivers/net/ethernet/qlogic/qed/qed_main.c b/drivers/net/ethernet/qlogic/qed/qed_main.c
index 2c189c6..016d658 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_main.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_main.c
@@ -1095,7 +1095,7 @@ static int qed_slowpath_delayed_work(struct qed_hwfn *hwfn,
 				     enum qed_slowpath_wq_flag wq_flag,
 				     unsigned long delay)
 {
-	if (!hwfn->slowpath_wq_active)
+	if (!test_bit(QED_SLOWPATH_ACTIVE, &hwfn->slowpath_task_flags))
 		return -EINVAL;
 
 	/* Memory barrier for setting atomic bit */
@@ -1133,7 +1133,8 @@ static void qed_slowpath_wq_stop(struct qed_dev *cdev)
 			continue;
 
 		/* Stop queuing new delayed works */
-		cdev->hwfns[i].slowpath_wq_active = false;
+		clear_bit(QED_SLOWPATH_ACTIVE,
+			  &cdev->hwfns[i].slowpath_task_flags);
 
 		/* Wait until the last periodic doorbell recovery is executed */
 		while (test_bit(QED_SLOWPATH_PERIODIC_DB_REC,
@@ -1153,7 +1154,7 @@ static void qed_slowpath_task(struct work_struct *work)
 	struct qed_ptt *ptt = qed_ptt_acquire(hwfn);
 
 	if (!ptt) {
-		if (hwfn->slowpath_wq_active)
+		if (test_bit(QED_SLOWPATH_ACTIVE, &hwfn->slowpath_task_flags))
 			queue_delayed_work(hwfn->slowpath_wq,
 					   &hwfn->slowpath_task, 0);
 
@@ -1199,7 +1200,7 @@ static int qed_slowpath_wq_start(struct qed_dev *cdev)
 		}
 
 		INIT_DELAYED_WORK(&hwfn->slowpath_task, qed_slowpath_task);
-		hwfn->slowpath_wq_active = true;
+		set_bit(QED_SLOWPATH_ACTIVE, &hwfn->slowpath_task_flags);
 	}
 
 	return 0;
-- 
1.8.3.1