target: Fix ordered task CHECK_CONDITION early exception handling

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@linux.vnet.ibm.com>
Signed-off-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Signed-off-by: Michael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a6e1edcfefbdc5a4677dc7c37a351c3ab7bd25f5..42c2a44b83ddbcb3183e92ec86be9ec38024d38e 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1827,6 +1827,8 @@ static bool target_handle_task_attr(struct se_cmd *cmd)
        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.
@@ -1949,6 +1951,9 @@ static void transport_complete_task_attr(struct se_cmd *cmd)
        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++;
@@ -1965,7 +1970,7 @@ static void transport_complete_task_attr(struct se_cmd *cmd)
                pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
                         dev->dev_cur_ordered_id);
        }
-
+restart:
        target_restart_delayed_cmds(dev);
 }
 

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index b316b44d03f3667fea87daef334a3e5a5060f5bc..fb8e3b6febdff7f5fdb3f0335455b9e074647c40 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -142,6 +142,7 @@ enum se_cmd_flags_table {
        SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC = 0x00200000,
        SCF_ACK_KREF                    = 0x00400000,
        SCF_USE_CPUID                   = 0x00800000,
+       SCF_TASK_ATTR_SET               = 0x01000000,
 };
 
 /*