lkml.org 
[lkml]   [2017]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/6] target: Fix quiese during transport_write_pending_qf endless loop
Date
From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a potential end-less loop during QUEUE_FULL,
where cmd->se_tfo->write_pending() callback fails repeatedly
but __transport_wait_for_tasks() has already been invoked to
quiese the outstanding se_cmd descriptor.

To address this bug, this patch adds a CMD_T_STOP|CMD_T_ABORTED
check within transport_write_pending_qf() and invokes the
existing se_cmd->t_transport_stop_comp to signal quiese
completion back to __transport_wait_for_tasks().

Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Cc: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: Potnuri Bharat Teja <bharat@chelsio.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/target/target_core_transport.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d02218c..0e89db8 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2560,7 +2560,20 @@ void transport_kunmap_data_sg(struct se_cmd *cmd)

static void transport_write_pending_qf(struct se_cmd *cmd)
{
+ unsigned long flags;
int ret;
+ bool stop;
+
+ spin_lock_irqsave(&cmd->t_state_lock, flags);
+ stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
+ spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+
+ if (stop) {
+ pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
+ __func__, __LINE__, cmd->tag);
+ complete_all(&cmd->t_transport_stop_comp);
+ return;
+ }

ret = cmd->se_tfo->write_pending(cmd);
if (ret) {
--
1.9.1
\
 
 \ /
  Last update: 2017-11-08 21:08    [W:0.079 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site