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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>
hifive-unleashed-5.1
Nicholas Bellinger 2016-06-13 22:58:09 -07:00
parent dff0ca9ea7
commit 410c29dfbf
2 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/target/target_core_transport.c
View File

@ -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);
}

1
include/target/target_core_base.h
View File

@ -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,
};
/*