diff options
| author | Roland Dreier <roland@purestorage.com> | 2015-07-23 14:53:32 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-08-02 23:11:52 -0700 |
| commit | 109e2381749c1cfd94a0d22b2b54142539024973 (patch) | |
| tree | 9695ecd3738a7bad43edcca4eb641339e7a30060 /drivers/target/iscsi/iscsi_target_configfs.c | |
| parent | 24c7d6c7316c72301bf8ecfc1189fd476176fd75 (diff) | |
| download | linux-109e2381749c1cfd94a0d22b2b54142539024973.tar.bz2 | |
target: Drop iSCSI use of mutex around max_cmd_sn increment
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.
(Get correct values for logging - fix whitespace damage)
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Spencer Baugh <sbaugh@catern.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/iscsi/iscsi_target_configfs.c')
| -rw-r--r-- | drivers/target/iscsi/iscsi_target_configfs.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index 05f16640fb9b..48f708bc101d 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -656,6 +656,7 @@ static ssize_t lio_target_nacl_show_info( struct iscsi_conn *conn; struct se_session *se_sess; ssize_t rb = 0; + u32 max_cmd_sn; spin_lock_bh(&se_nacl->nacl_sess_lock); se_sess = se_nacl->nacl_sess; @@ -703,11 +704,12 @@ static ssize_t lio_target_nacl_show_info( " Values]-----------------------\n"); rb += sprintf(page+rb, " CmdSN/WR : CmdSN/WC : ExpCmdSN" " : MaxCmdSN : ITT : TTT\n"); + max_cmd_sn = (u32) atomic_read(&sess->max_cmd_sn); rb += sprintf(page+rb, " 0x%08x 0x%08x 0x%08x 0x%08x" " 0x%08x 0x%08x\n", sess->cmdsn_window, - (sess->max_cmd_sn - sess->exp_cmd_sn) + 1, - sess->exp_cmd_sn, sess->max_cmd_sn, + (max_cmd_sn - sess->exp_cmd_sn) + 1, + sess->exp_cmd_sn, max_cmd_sn, sess->init_task_tag, sess->targ_xfer_tag); rb += sprintf(page+rb, "----------------------[iSCSI" " Connections]-------------------------\n"); |