From 5e8e6b4b3adebf01a9d97056cbbfd8c44330df99 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 12 Nov 2013 17:54:56 -0800 Subject: iscsi-target: Fix mutex_trylock usage in iscsit_increment_maxcmdsn 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 Cc: # v3.10+ Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target_device.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'drivers/target/iscsi/iscsi_target_device.c') diff --git a/drivers/target/iscsi/iscsi_target_device.c b/drivers/target/iscsi/iscsi_target_device.c index 6c7a5104a4cd..7087c736daa5 100644 --- a/drivers/target/iscsi/iscsi_target_device.c +++ b/drivers/target/iscsi/iscsi_target_device.c @@ -58,11 +58,7 @@ 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); -- cgit v1.2.2