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authorNicholas Bellinger <nab@linux-iscsi.org>2013-11-12 17:54:56 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-04 10:56:14 -0800
commitcf516effc76c78f948e6eb7cc46d4515003b423d (patch)
tree24bfa271ec40ccf9bcc5938ba91786801a7830c3 /drivers/target
parent61688ba3da37952114be1bef89e2f4a3b0217624 (diff)
downloadlinux-linaro-stable-cf516effc76c78f948e6eb7cc46d4515003b423d.tar.gz
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 <moussaba@micron.com> Tested-by: Moussa Ba <moussaba@micron.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/iscsi/iscsi_target_configfs.c5
-rw-r--r--drivers/target/iscsi/iscsi_target_device.c6
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 421344da8b51..c45b3365d63d 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 1b74033510a0..4edcc47c0634 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);