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Message-Id: <20160818135611.924139356@linuxfoundation.org>
Date: Thu, 18 Aug 2016 15:58:54 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
"Bryant G. Ly" <bryantly@...ux.vnet.ibm.com>,
Michael Cyr <mikecyr@...ux.vnet.ibm.com>,
Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [PATCH 4.4 124/138] target: Fix ordered task CHECK_CONDITION early exception handling
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@...ux-iscsi.org>
commit 410c29dfbfdf73d0d0b5d14a21868ab038eca703 upstream.
If a Simple command is sent with a failure, target_setup_cmd_from_cdb
returns with TCM_UNSUPPORTED_SCSI_OPCODE or TCM_INVALID_CDB_FIELD.
So in the cases where target_setup_cmd_from_cdb returns an error, we
never get far enough to call target_execute_cmd to increment simple_cmds.
Since simple_cmds isn't incremented, the result of the failure from
target_setup_cmd_from_cdb causes transport_generic_request_failure to
decrement simple_cmds, due to call to transport_complete_task_attr.
With this dev->simple_cmds or dev->dev_ordered_sync is now -1, not 0.
So when a subsequent command with an Ordered Task is sent, it causes
a hang, since dev->simple_cmds is at -1.
Tested-by: Bryant G. Ly <bryantly@...ux.vnet.ibm.com>
Signed-off-by: Bryant G. Ly <bryantly@...ux.vnet.ibm.com>
Tested-by: Michael Cyr <mikecyr@...ux.vnet.ibm.com>
Signed-off-by: Michael Cyr <mikecyr@...ux.vnet.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/target/target_core_transport.c | 7 ++++++-
include/target/target_core_base.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1815,6 +1815,8 @@ static bool target_handle_task_attr(stru
if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
return false;
+ cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
+
/*
* Check for the existence of HEAD_OF_QUEUE, and if true return 1
* to allow the passed struct se_cmd list of tasks to the front of the list.
@@ -1937,6 +1939,9 @@ static void transport_complete_task_attr
if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
return;
+ if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
+ goto restart;
+
if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
atomic_dec_mb(&dev->simple_cmds);
dev->dev_cur_ordered_id++;
@@ -1953,7 +1958,7 @@ static void transport_complete_task_attr
pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
dev->dev_cur_ordered_id);
}
-
+restart:
target_restart_delayed_cmds(dev);
}
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -139,6 +139,7 @@ enum se_cmd_flags_table {
SCF_COMPARE_AND_WRITE_POST = 0x00100000,
SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC = 0x00200000,
SCF_ACK_KREF = 0x00400000,
+ SCF_TASK_ATTR_SET = 0x01000000,
};
/* struct se_dev_entry->lun_flags and struct se_lun->lun_access */
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