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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: target-devel@vger.kernel.org
Cc: linux-scsi@vger.kernel.org,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Ahmed S . Darwish" <a.darwish@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 1/6] scsi: target: iscsi: Avoid in_interrupt() usage in iscsit_close_session().
Date: Sun, 20 Dec 2020 21:36:33 +0100
Message-ID: <20201220203638.43615-2-bigeasy@linutronix.de> (raw)
In-Reply-To: <20201220203638.43615-1-bigeasy@linutronix.de>

iscsit_close_session() uses in_interrupt() to decide if it needs to
check the return value of iscsit_check_session_usage_count() if it was
not able to sleep.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

iscsit_close_session() has two callers:
- iscsit_handle_time2retain_timeout()
  A timer_list callback.

- iscsit_close_connection()
  Runs in preemptible context, acquires a mutex.

Add an argument to iscsit_close_session() indicating if sleeping is
possible.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/target/iscsi/iscsi_target.c      | 10 +++++-----
 drivers/target/iscsi/iscsi_target.h      |  2 +-
 drivers/target/iscsi/iscsi_target_erl0.c |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 518fac4864cfa..5abf03125388a 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -4327,7 +4327,7 @@ int iscsit_close_connection(
 	     atomic_read(&sess->session_fall_back_to_erl0)) {
 		spin_unlock_bh(&sess->conn_lock);
 		complete_all(&sess->session_wait_comp);
-		iscsit_close_session(sess);
+		iscsit_close_session(sess, true);
 
 		return 0;
 	} else if (atomic_read(&sess->session_logout)) {
@@ -4337,7 +4337,7 @@ int iscsit_close_connection(
 		if (atomic_read(&sess->session_close)) {
 			spin_unlock_bh(&sess->conn_lock);
 			complete_all(&sess->session_wait_comp);
-			iscsit_close_session(sess);
+			iscsit_close_session(sess, true);
 		} else {
 			spin_unlock_bh(&sess->conn_lock);
 		}
@@ -4353,7 +4353,7 @@ int iscsit_close_connection(
 		if (atomic_read(&sess->session_close)) {
 			spin_unlock_bh(&sess->conn_lock);
 			complete_all(&sess->session_wait_comp);
-			iscsit_close_session(sess);
+			iscsit_close_session(sess, true);
 		} else {
 			spin_unlock_bh(&sess->conn_lock);
 		}
@@ -4366,7 +4366,7 @@ int iscsit_close_connection(
  * If the iSCSI Session for the iSCSI Initiator Node exists,
  * forcefully shutdown the iSCSI NEXUS.
  */
-int iscsit_close_session(struct iscsi_session *sess)
+int iscsit_close_session(struct iscsi_session *sess, bool can_sleep)
 {
 	struct iscsi_portal_group *tpg = sess->tpg;
 	struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
@@ -4399,7 +4399,7 @@ int iscsit_close_session(struct iscsi_session *sess)
 	 * time2retain handler) and contain and active session usage count we
 	 * restart the timer and exit.
 	 */
-	if (!in_interrupt()) {
+	if (can_sleep) {
 		iscsit_check_session_usage_count(sess);
 	} else {
 		if (iscsit_check_session_usage_count(sess) == 2) {
diff --git a/drivers/target/iscsi/iscsi_target.h b/drivers/target/iscsi/iscsi_target.h
index 7409ce2a66078..b35a96ded9c19 100644
--- a/drivers/target/iscsi/iscsi_target.h
+++ b/drivers/target/iscsi/iscsi_target.h
@@ -41,7 +41,7 @@ extern void iscsit_thread_get_cpumask(struct iscsi_conn *);
 extern int iscsi_target_tx_thread(void *);
 extern int iscsi_target_rx_thread(void *);
 extern int iscsit_close_connection(struct iscsi_conn *);
-extern int iscsit_close_session(struct iscsi_session *);
+extern int iscsit_close_session(struct iscsi_session *, bool can_sleep);
 extern void iscsit_fail_session(struct iscsi_session *);
 extern void iscsit_stop_session(struct iscsi_session *, int, int);
 extern int iscsit_release_sessions_for_tpg(struct iscsi_portal_group *, int);
diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index b4abd7b68e6da..102c9cbf59f38 100644
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -765,7 +765,7 @@ void iscsit_handle_time2retain_timeout(struct timer_list *t)
 
 	iscsit_fill_cxn_timeout_err_stats(sess);
 	spin_unlock_bh(&se_tpg->session_lock);
-	iscsit_close_session(sess);
+	iscsit_close_session(sess, false);
 }
 
 void iscsit_start_time2retain_handler(struct iscsi_session *sess)
-- 
2.29.2


  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-20 20:36 [PATCH 0/6] scsi: target: Remove in_interrupt() usage Sebastian Andrzej Siewior
2020-12-20 20:36 ` Sebastian Andrzej Siewior [this message]
2020-12-20 20:36 ` [PATCH 2/6] scsi: target: iscsi: Avoid in_interrupt() usage in iscsit_check_session_usage_count() Sebastian Andrzej Siewior
2020-12-20 20:36 ` [PATCH 3/6] scsi: target: iscsi: Redo iscsit_check_session_usage_count() return code Sebastian Andrzej Siewior
2020-12-20 20:36 ` [PATCH 4/6] scsi: target: Remove in_interrupt() usage in core_alua_check_nonop_delay() Sebastian Andrzej Siewior
2020-12-20 20:36 ` [PATCH 5/6] scsi: target: Replace in_interrupt() usage in target_submit_cmd_map_sgls() Sebastian Andrzej Siewior
2020-12-20 20:36 ` [PATCH 6/6] scsi: target: Remove in_interrupt() check in transport_handle_cdb_direct() Sebastian Andrzej Siewior
2021-01-22 16:51 ` [PATCH 0/6] scsi: target: Remove in_interrupt() usage Sebastian Andrzej Siewior
2021-01-23  1:28   ` Martin K. Petersen
2021-01-27  4:54 ` Martin K. Petersen

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