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authorMike Christie <michaelc@cs.wisc.edu>2009-08-20 15:11:03 -0500
committerJames Bottomley <James.Bottomley@suse.de>2009-09-05 09:42:48 -0500
commit70b31c152dc49ef70bd2b34ad53ccbd9bb4116d4 (patch)
tree9d3c857ed4604b7843a0bec05e85afb095228082
parentd1af8a328755f51c9b76157a8692e56520d3fd94 (diff)
[SCSI] libiscsi, iscsi_tcp: check suspend bit before each call to xmit_task
If we had multiple tasks on the cmd or requeue lists, and iscsi_tcp returns a error, the write_space function can still run and queue iscsi_data_xmit. If it was a legetimate problem and iscsi_conn_failure was run but we raced and iscsi_data_xmit was run first it could miss the suspend bit checks, and start trying to send data again and hit another timeout. A similar problem is present when using cxgb3i. This has libiscsi check the suspend bit before calling the xmit task callout, so we at least do not try sending multiple tasks (one could be sent). Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
-rw-r--r--drivers/scsi/libiscsi.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 1d7a8b7e8a7..a7ee4bb4070 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1280,6 +1280,9 @@ static int iscsi_xmit_task(struct iscsi_conn *conn)
struct iscsi_task *task = conn->task;
int rc;
+ if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx))
+ return -ENODATA;
+
__iscsi_get_task(task);
spin_unlock_bh(&conn->session->lock);
rc = conn->session->tt->xmit_task(task);
@@ -1329,7 +1332,7 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
int rc = 0;
spin_lock_bh(&conn->session->lock);
- if (unlikely(conn->suspend_tx)) {
+ if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
spin_unlock_bh(&conn->session->lock);
return -ENODATA;
@@ -1338,7 +1341,7 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
if (conn->task) {
rc = iscsi_xmit_task(conn);
if (rc)
- goto again;
+ goto done;
}
/*
@@ -1358,7 +1361,7 @@ check_mgmt:
}
rc = iscsi_xmit_task(conn);
if (rc)
- goto again;
+ goto done;
}
/* process pending command queue */
@@ -1379,14 +1382,14 @@ check_mgmt:
list_add_tail(&conn->task->running,
&conn->cmdqueue);
conn->task = NULL;
- goto again;
+ goto done;
} else
fail_scsi_task(conn->task, DID_ABORT);
continue;
}
rc = iscsi_xmit_task(conn);
if (rc)
- goto again;
+ goto done;
/*
* we could continuously get new task requests so
* we need to check the mgmt queue for nops that need to
@@ -1412,16 +1415,14 @@ check_mgmt:
conn->task->state = ISCSI_TASK_RUNNING;
rc = iscsi_xmit_task(conn);
if (rc)
- goto again;
+ goto done;
if (!list_empty(&conn->mgmtqueue))
goto check_mgmt;
}
spin_unlock_bh(&conn->session->lock);
return -ENODATA;
-again:
- if (unlikely(conn->suspend_tx))
- rc = -ENODATA;
+done:
spin_unlock_bh(&conn->session->lock);
return rc;
}