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[SCSI] iscsi: fix writepsace race

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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>
This commit is contained in:
Mike Christie
2006-05-30 00:37:28 -05:00
committed by James Bottomley
parent 040515f53c
commit 3219e52941
3 changed files with 126 additions and 95 deletions
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31
drivers/scsi/libiscsi.c
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@@ -513,10 +513,11 @@ EXPORT_SYMBOL_GPL(iscsi_conn_failure);
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 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
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 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
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 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
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 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
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);
}