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Message-Id: <1384308703-10034-1-git-send-email-nab@daterainc.com>
Date: Wed, 13 Nov 2013 02:11:41 +0000
From: "Nicholas A. Bellinger" <nab@...erainc.com>
To: target-devel <target-devel@...r.kernel.org>
Cc: linux-scsi <linux-scsi@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
Moussa Ba <moussaba@...ron.com>,
Or Gerlitz <ogerlitz@...lanox.com>,
Mike Christie <michaelc@...wisc.edu>,
Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [PATCH 0/2] iscsi/iser-target: Fix
From: Nicholas Bellinger <nab@...ux-iscsi.org>
Hi folks,
Here are the two patches to address the regression bug that Moussa
has recently been hitting with ib_isert ports + mtip32xx backends.
In the end, this bug was due to an incorrect usage of mutex_trylock(),
that was originally introduced to avoid an ib_isert specific nested
deadlock from an exception path, that inadvertently allowed normal
per RX/TX process context contention to increment sess->max_cmd_sn +
post a response + receive a new command in RX context with a CmdSN
larger than the last MaxCmdSN sychronized across RX/TX contexts.
This patch simply avoids the ib_isert callback in lio_queue_status()
for the special iscsi_execute_cmd() exception cases to avoid the
dead-lock, which allows the problematic mutex_trylock() usage in
iscsit_increment_maxcmdsn() to go away entirely.
I'll be including both of these with a CC' to stable for v3.10+
Special thanks to Moussa for helping track this bug down.
--nab
Nicholas Bellinger (2):
iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn
ib_isert: Avoid duplicate iscsit_increment_maxcmdsn call
drivers/infiniband/ulp/isert/ib_isert.c | 6 +-----
drivers/target/iscsi/iscsi_target_configfs.c | 5 +++++
drivers/target/iscsi/iscsi_target_device.c | 6 +-----
3 files changed, 7 insertions(+), 10 deletions(-)
--
1.7.10.4
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