[PATCH 0/2] iscsi/iser-target: Fix

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

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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