From cf516effc76c78f948e6eb7cc46d4515003b423d Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 12 Nov 2013 17:54:56 -0800 Subject: [PATCH] iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn commit 5e8e6b4b3adebf01a9d97056cbbfd8c44330df99 upstream. This patch fixes a >= v3.10 regression bug with mutex_trylock() usage within iscsit_increment_maxcmdsn(), that was originally added to allow for a special case where ->cmdsn_mutex was already held from the iscsit_execute_cmd() exception path for ib_isert. When !mutex_trylock() was occuring under contention during normal RX/TX process context codepaths, the bug was manifesting itself as the following protocol error: Received CmdSN: 0x000fcbb7 is greater than MaxCmdSN: 0x000fcbb6, protocol error. Received CmdSN: 0x000fcbb8 is greater than MaxCmdSN: 0x000fcbb6, protocol error. This patch simply avoids the direct ib_isert callback in lio_queue_status() for the special iscsi_execute_cmd() exception cases, that allows the problematic mutex_trylock() usage in iscsit_increment_maxcmdsn() to go away. Reported-by: Moussa Ba Tested-by: Moussa Ba Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target_configfs.c | 5 +++++ drivers/target/iscsi/iscsi_target_device.c | 6 +----- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c index 421344d..c45b336 100644 --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -1650,6 +1650,11 @@ static int lio_queue_status(struct se_cmd *se_cmd) struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd); cmd->i_state = ISTATE_SEND_STATUS; + + if (cmd->se_cmd.scsi_status || cmd->sense_reason) { + iscsit_add_cmd_to_response_queue(cmd, cmd->conn, cmd->i_state); + return 0; + } cmd->conn->conn_transport->iscsit_queue_status(cmd->conn, cmd); return 0; diff --git a/drivers/target/iscsi/iscsi_target_device.c b/drivers/target/iscsi/iscsi_target_device.c index 1b74033..4edcc47 100644 --- a/drivers/target/iscsi/iscsi_target_device.c +++ b/drivers/target/iscsi/iscsi_target_device.c @@ -60,11 +60,7 @@ void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess cmd->maxcmdsn_inc = 1; - if (!mutex_trylock(&sess->cmdsn_mutex)) { - sess->max_cmd_sn += 1; - pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn); - return; - } + mutex_lock(&sess->cmdsn_mutex); sess->max_cmd_sn += 1; pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn); mutex_unlock(&sess->cmdsn_mutex); -- 2.7.4