2017-11-08 04:36:00

by Nicholas A. Bellinger

[permalink] [raw]
Subject: [PATCH 3/6] target: Fix quiese during transport_write_pending_qf endless loop

From: Nicholas Bellinger <[email protected]>

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 <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Bryant G. Ly <[email protected]>
Cc: Michael Cyr <[email protected]>
Cc: Potnuri Bharat Teja <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Signed-off-by: Nicholas Bellinger <[email protected]>
---
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


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