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From: Mike Christie <michael.christie@oracle.com>
To: lduncan@suse.com, cleech@redhat.com, njavali@marvell.com,
	mrangankar@marvell.com, GR-QLogic-Storage-Upstream@marvell.com,
	varun@chelsio.com, martin.petersen@oracle.com,
	linux-scsi@vger.kernel.org, jejb@linux.ibm.com
Subject: [PATCH 21/22] libiscsi: drop back_lock from xmit path
Date: Thu, 17 Dec 2020 00:42:11 -0600	[thread overview]
Message-ID: <1608187332-4434-22-git-send-email-michael.christie@oracle.com> (raw)
In-Reply-To: <1608187332-4434-1-git-send-email-michael.christie@oracle.com>

We have a proper refcount on the task so if we get a rsp while R2Ts are
queued then we will not crash. We only need to check if a rsp has been
processed and if we race it's ok since with a bad target we could get
this rsp at any time like after dropping the lock and starting to send
data so the lock use doesn't matter.

This patch just drops the lock since we will eventually either see
the updated state and stop early or we will send all the data. Either
way we will not free the task until all refs have been dropped.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
 drivers/scsi/libiscsi.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 869c38d..6516900 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1473,8 +1473,6 @@ static int iscsi_xmit_task(struct iscsi_conn *conn, bool has_extra_ref)
 		/* done with this task */
 		task->last_xfer = jiffies;
 	}
-	/* regular RX path uses back_lock */
-	spin_lock(&conn->session->back_lock);
 	if (rc && task->state == ISCSI_TASK_RUNNING) {
 		/*
 		 * get an extra ref that is released next time we access it
@@ -1483,7 +1481,6 @@ static int iscsi_xmit_task(struct iscsi_conn *conn, bool has_extra_ref)
 		iscsi_get_task(task);
 		conn->task = task;
 	}
-	spin_unlock(&conn->session->back_lock);
 
 put_task:
 	iscsi_put_task(task);
-- 
1.8.3.1


  parent reply	other threads:[~2020-12-17  6:43 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-17  6:41 [RFC PATCH 00/22 V3] iscsi: lock clean ups Mike Christie
2020-12-17  6:41 ` [PATCH 01/22] libiscsi: fix iscsi_prep_scsi_cmd_pdu error handling Mike Christie
2020-12-17  6:41 ` [PATCH 02/22] libiscsi: drop taskqueuelock Mike Christie
2020-12-17  6:41 ` [PATCH 03/22] libiscsi: fix iscsi_task use after free Mike Christie
2020-12-17  6:41 ` [PATCH 04/22] qla4xxx: use iscsi_is_session_online Mike Christie
2020-12-17  6:41 ` [PATCH 05/22] iscsi class: drop session lock in iscsi_session_chkready Mike Christie
2020-12-17  6:41 ` [PATCH 06/22] libiscsi: remove queued_cmdsn Mike Christie
2020-12-17  6:41 ` [PATCH 07/22] libiscsi: drop frwd lock for session state Mike Christie
2020-12-17  6:41 ` [PATCH 08/22] libiscsi: add task prealloc/free callouts Mike Christie
2020-12-17  6:41 ` [PATCH 09/22] qedi: implement alloc_task_priv/free_task_priv Mike Christie
2020-12-17  6:42 ` [PATCH 10/22] bnx2i: " Mike Christie
2020-12-17  6:42 ` [PATCH 11/22] iser, be2iscsi, qla4xxx: set scsi_host_template cmd_size Mike Christie
2020-12-17  6:42 ` [PATCH 12/22] bnx2i: " Mike Christie
2020-12-17  6:42 ` [PATCH 13/22] qedi: " Mike Christie
2020-12-17  6:42 ` [PATCH 14/22] iscsi_tcp, libcxgbi: " Mike Christie
2020-12-17  6:42 ` [PATCH 15/22] libiscsi: use scsi_host_busy_iter Mike Christie
2020-12-17  6:42 ` [PATCH 16/22] be2iscsi: " Mike Christie
2020-12-17  6:42 ` [PATCH 17/22] bnx2i: prep driver for switch to blk tags Mike Christie
2020-12-17  6:42 ` [PATCH 18/22] qedi: " Mike Christie
2020-12-17  6:42 ` [PATCH 19/22] libiscsi: use blk/scsi-ml mq cmd pre-allocator Mike Christie
2020-12-17  6:42 ` [PATCH 20/22] libiscsi: rm iscsi_put_task back_lock requirement Mike Christie
2020-12-17  6:42 ` Mike Christie [this message]
2020-12-17  6:42 ` [PATCH 22/22] libiscsi: fix conn_send_pdu API Mike Christie

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