On Thu, 2015-07-23 at 14:53 -0700, Spencer Baugh wrote:

From: Roland Dreier <redacted>

In a performance profile, taking a mutex in iscsit_increment_maxcmdsn()
shows up very high.  However taking a mutex around "sess->max_cmd_sn += 1"
seems pretty silly: we're not serializing against other contexts in
any useful way.

I did a quick audit and there don't appear to be any other places that
use max_cmd_sn within the mutex more than once, so this lock can't be
providing any useful serialization.

v2: Get correct values for logging
v3: Fix whitespace damage

Signed-off-by: Roland Dreier <redacted>
Signed-off-by: Spencer Baugh <redacted>
---
 drivers/target/iscsi/iscsi_target.c          | 18 +++++++++---------
 drivers/target/iscsi/iscsi_target_configfs.c |  6 ++++--
 drivers/target/iscsi/iscsi_target_device.c   |  7 ++-----
 drivers/target/iscsi/iscsi_target_login.c    |  2 +-
 drivers/target/iscsi/iscsi_target_nego.c     |  9 +++------
 drivers/target/iscsi/iscsi_target_tmr.c      |  2 +-
 drivers/target/iscsi/iscsi_target_util.c     |  7 ++++---
 include/target/iscsi/iscsi_target_core.h     |  2 +-
 8 files changed, 25 insertions(+), 28 deletions(-)

A nice optimization for iscsi-target + ib_isert on this patch.

Applied to target-pending/for-next. 

Thanks Roland & Co.