[SCSI] iscsi: fix writepsace race
We can race and misset the suspend bit if iscsi_write_space is
called then iscsi_send returns with a failure indicating
there is no space.
To handle this this patch returns a error upwards allowing xmitworker
to decide if we need to try and transmit again. For the no
write space case xmitworker will not retry, and instead
let iscsi_write_space queue it back up if needed (this relies
on the work queue code to properly requeue us if needed).
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 256b87a..2673a11 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -513,10 +513,11 @@
static int iscsi_data_xmit(struct iscsi_conn *conn)
{
struct iscsi_transport *tt;
+ int rc = 0;
if (unlikely(conn->suspend_tx)) {
debug_scsi("conn %d Tx suspended!\n", conn->id);
- return 0;
+ return -ENODATA;
}
tt = conn->session->tt;
@@ -536,13 +537,15 @@
BUG_ON(conn->ctask && conn->mtask);
if (conn->ctask) {
- if (tt->xmit_cmd_task(conn, conn->ctask))
+ rc = tt->xmit_cmd_task(conn, conn->ctask);
+ if (rc)
goto again;
/* done with this in-progress ctask */
conn->ctask = NULL;
}
if (conn->mtask) {
- if (tt->xmit_mgmt_task(conn, conn->mtask))
+ rc = tt->xmit_mgmt_task(conn, conn->mtask);
+ if (rc)
goto again;
/* done with this in-progress mtask */
conn->mtask = NULL;
@@ -556,7 +559,8 @@
list_add_tail(&conn->mtask->running,
&conn->mgmt_run_list);
spin_unlock_bh(&conn->session->lock);
- if (tt->xmit_mgmt_task(conn, conn->mtask))
+ rc = tt->xmit_mgmt_task(conn, conn->mtask);
+ if (rc)
goto again;
}
/* done with this mtask */
@@ -574,7 +578,8 @@
if (list_empty(&conn->ctask->running))
list_add_tail(&conn->ctask->running, &conn->run_list);
spin_unlock_bh(&conn->session->lock);
- if (tt->xmit_cmd_task(conn, conn->ctask))
+ rc = tt->xmit_cmd_task(conn, conn->ctask);
+ if (rc)
goto again;
}
/* done with this ctask */
@@ -588,32 +593,34 @@
list_add_tail(&conn->mtask->running,
&conn->mgmt_run_list);
spin_unlock_bh(&conn->session->lock);
- if (tt->xmit_mgmt_task(conn, conn->mtask))
+ rc = tt->xmit_mgmt_task(conn, conn->mtask);
+ if (rc)
goto again;
}
/* done with this mtask */
conn->mtask = NULL;
}
- return 0;
+ return -ENODATA;
again:
if (unlikely(conn->suspend_tx))
- return 0;
+ return -ENODATA;
- return -EAGAIN;
+ return rc;
}
static void iscsi_xmitworker(void *data)
{
struct iscsi_conn *conn = data;
-
+ int rc;
/*
* serialize Xmit worker on a per-connection basis.
*/
mutex_lock(&conn->xmitmutex);
- if (iscsi_data_xmit(conn))
- scsi_queue_work(conn->session->host, &conn->xmitwork);
+ do {
+ rc = iscsi_data_xmit(conn);
+ } while (rc >= 0 || rc == -EAGAIN);
mutex_unlock(&conn->xmitmutex);
}