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From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: target-devel@vger.kernel.org,
	Bart Van Assche <bvanassche@acm.org>,
	Pavel Zakharov <pavel.zakharov@delphix.com>,
	Mike Christie <mchristi@redhat.com>,
	stable@vger.kernel.org
Subject: [PATCH] Revert "target/core: Inline transport_lun_remove_cmd()"
Date: Mon, 10 Feb 2020 05:12:02 +0000	[thread overview]
Message-ID: <20200210051202.12934-1-bvanassche@acm.org> (raw)

Commit 83f85b8ec305 postponed the percpu_ref_put(&se_cmd->se_lun->lun_ref)
call from command completion to the time when the final command reference
is dropped. That approach is not compatible with the iSCSI target driver
because the iSCSI target driver keeps the command with the highest stat_sn
after it has completed until the next command is received (see also
iscsit_ack_from_expstatsn()). Fix this regression by reverting commit
83f85b8ec305.

Reported-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Cc: Pavel Zakharov <pavel.zakharov@delphix.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: <stable@vger.kernel.org>
Fixes: 83f85b8ec305 ("scsi: target/core: Inline transport_lun_remove_cmd()")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/target/target_core_transport.c | 31 +++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index ea482d4b1f00..0ae9e60fc4d5 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -666,6 +666,11 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 
 	target_remove_from_state_list(cmd);
 
+	/*
+	 * Clear struct se_cmd->se_lun before the handoff to FE.
+	 */
+	cmd->se_lun = NULL;
+
 	spin_lock_irqsave(&cmd->t_state_lock, flags);
 	/*
 	 * Determine if frontend context caller is requesting the stopping of
@@ -693,6 +698,17 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 	return cmd->se_tfo->check_stop_free(cmd);
 }
 
+static void transport_lun_remove_cmd(struct se_cmd *cmd)
+{
+	struct se_lun *lun = cmd->se_lun;
+
+	if (!lun)
+		return;
+
+	if (cmpxchg(&cmd->lun_ref_active, true, false))
+		percpu_ref_put(&lun->lun_ref);
+}
+
 static void target_complete_failure_work(struct work_struct *work)
 {
 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
@@ -783,6 +799,8 @@ static void target_handle_abort(struct se_cmd *cmd)
 
 	WARN_ON_ONCE(kref_read(&cmd->cmd_kref) = 0);
 
+	transport_lun_remove_cmd(cmd);
+
 	transport_cmd_check_stop_to_fabric(cmd);
 }
 
@@ -1708,6 +1726,7 @@ static void target_complete_tmr_failure(struct work_struct *work)
 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
 
+	transport_lun_remove_cmd(se_cmd);
 	transport_cmd_check_stop_to_fabric(se_cmd);
 }
 
@@ -1898,6 +1917,7 @@ void transport_generic_request_failure(struct se_cmd *cmd,
 		goto queue_full;
 
 check_stop:
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 	return;
 
@@ -2195,6 +2215,7 @@ static void transport_complete_qf(struct se_cmd *cmd)
 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
 		return;
 	}
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 }
 
@@ -2289,6 +2310,7 @@ static void target_complete_ok_work(struct work_struct *work)
 		if (ret)
 			goto queue_full;
 
+		transport_lun_remove_cmd(cmd);
 		transport_cmd_check_stop_to_fabric(cmd);
 		return;
 	}
@@ -2314,6 +2336,7 @@ static void target_complete_ok_work(struct work_struct *work)
 			if (ret)
 				goto queue_full;
 
+			transport_lun_remove_cmd(cmd);
 			transport_cmd_check_stop_to_fabric(cmd);
 			return;
 		}
@@ -2349,6 +2372,7 @@ static void target_complete_ok_work(struct work_struct *work)
 			if (ret)
 				goto queue_full;
 
+			transport_lun_remove_cmd(cmd);
 			transport_cmd_check_stop_to_fabric(cmd);
 			return;
 		}
@@ -2384,6 +2408,7 @@ static void target_complete_ok_work(struct work_struct *work)
 		break;
 	}
 
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 	return;
 
@@ -2710,6 +2735,9 @@ int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
 		 */
 		if (cmd->state_active)
 			target_remove_from_state_list(cmd);
+
+		if (cmd->se_lun)
+			transport_lun_remove_cmd(cmd);
 	}
 	if (aborted)
 		cmd->free_compl = &compl;
@@ -2781,9 +2809,6 @@ static void target_release_cmd_kref(struct kref *kref)
 	struct completion *abrt_compl = se_cmd->abrt_compl;
 	unsigned long flags;
 
-	if (se_cmd->lun_ref_active)
-		percpu_ref_put(&se_cmd->se_lun->lun_ref);
-
 	if (se_sess) {
 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 		list_del_init(&se_cmd->se_cmd_list);

WARNING: multiple messages have this Message-ID
From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: target-devel@vger.kernel.org,
	Bart Van Assche <bvanassche@acm.org>,
	Pavel Zakharov <pavel.zakharov@delphix.com>,
	Mike Christie <mchristi@redhat.com>,
	stable@vger.kernel.org
Subject: [PATCH] Revert "target/core: Inline transport_lun_remove_cmd()"
Date: Sun,  9 Feb 2020 21:12:02 -0800	[thread overview]
Message-ID: <20200210051202.12934-1-bvanassche@acm.org> (raw)

Commit 83f85b8ec305 postponed the percpu_ref_put(&se_cmd->se_lun->lun_ref)
call from command completion to the time when the final command reference
is dropped. That approach is not compatible with the iSCSI target driver
because the iSCSI target driver keeps the command with the highest stat_sn
after it has completed until the next command is received (see also
iscsit_ack_from_expstatsn()). Fix this regression by reverting commit
83f85b8ec305.

Reported-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Cc: Pavel Zakharov <pavel.zakharov@delphix.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: <stable@vger.kernel.org>
Fixes: 83f85b8ec305 ("scsi: target/core: Inline transport_lun_remove_cmd()")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/target/target_core_transport.c | 31 +++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index ea482d4b1f00..0ae9e60fc4d5 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -666,6 +666,11 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 
 	target_remove_from_state_list(cmd);
 
+	/*
+	 * Clear struct se_cmd->se_lun before the handoff to FE.
+	 */
+	cmd->se_lun = NULL;
+
 	spin_lock_irqsave(&cmd->t_state_lock, flags);
 	/*
 	 * Determine if frontend context caller is requesting the stopping of
@@ -693,6 +698,17 @@ static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 	return cmd->se_tfo->check_stop_free(cmd);
 }
 
+static void transport_lun_remove_cmd(struct se_cmd *cmd)
+{
+	struct se_lun *lun = cmd->se_lun;
+
+	if (!lun)
+		return;
+
+	if (cmpxchg(&cmd->lun_ref_active, true, false))
+		percpu_ref_put(&lun->lun_ref);
+}
+
 static void target_complete_failure_work(struct work_struct *work)
 {
 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
@@ -783,6 +799,8 @@ static void target_handle_abort(struct se_cmd *cmd)
 
 	WARN_ON_ONCE(kref_read(&cmd->cmd_kref) == 0);
 
+	transport_lun_remove_cmd(cmd);
+
 	transport_cmd_check_stop_to_fabric(cmd);
 }
 
@@ -1708,6 +1726,7 @@ static void target_complete_tmr_failure(struct work_struct *work)
 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
 
+	transport_lun_remove_cmd(se_cmd);
 	transport_cmd_check_stop_to_fabric(se_cmd);
 }
 
@@ -1898,6 +1917,7 @@ void transport_generic_request_failure(struct se_cmd *cmd,
 		goto queue_full;
 
 check_stop:
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 	return;
 
@@ -2195,6 +2215,7 @@ static void transport_complete_qf(struct se_cmd *cmd)
 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
 		return;
 	}
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 }
 
@@ -2289,6 +2310,7 @@ static void target_complete_ok_work(struct work_struct *work)
 		if (ret)
 			goto queue_full;
 
+		transport_lun_remove_cmd(cmd);
 		transport_cmd_check_stop_to_fabric(cmd);
 		return;
 	}
@@ -2314,6 +2336,7 @@ static void target_complete_ok_work(struct work_struct *work)
 			if (ret)
 				goto queue_full;
 
+			transport_lun_remove_cmd(cmd);
 			transport_cmd_check_stop_to_fabric(cmd);
 			return;
 		}
@@ -2349,6 +2372,7 @@ static void target_complete_ok_work(struct work_struct *work)
 			if (ret)
 				goto queue_full;
 
+			transport_lun_remove_cmd(cmd);
 			transport_cmd_check_stop_to_fabric(cmd);
 			return;
 		}
@@ -2384,6 +2408,7 @@ static void target_complete_ok_work(struct work_struct *work)
 		break;
 	}
 
+	transport_lun_remove_cmd(cmd);
 	transport_cmd_check_stop_to_fabric(cmd);
 	return;
 
@@ -2710,6 +2735,9 @@ int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
 		 */
 		if (cmd->state_active)
 			target_remove_from_state_list(cmd);
+
+		if (cmd->se_lun)
+			transport_lun_remove_cmd(cmd);
 	}
 	if (aborted)
 		cmd->free_compl = &compl;
@@ -2781,9 +2809,6 @@ static void target_release_cmd_kref(struct kref *kref)
 	struct completion *abrt_compl = se_cmd->abrt_compl;
 	unsigned long flags;
 
-	if (se_cmd->lun_ref_active)
-		percpu_ref_put(&se_cmd->se_lun->lun_ref);
-
 	if (se_sess) {
 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 		list_del_init(&se_cmd->se_cmd_list);

             reply	other threads:[~2020-02-10  5:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10  5:12 Bart Van Assche [this message]
2020-02-10  5:12 ` Bart Van Assche
2020-02-10 15:35 ` Pavel Zakharov
2020-02-10 15:35   ` Pavel Zakharov
2020-02-12 23:51 ` Martin K. Petersen
2020-02-12 23:51   ` Martin K. Petersen

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