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Commit 410c29df authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

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: default avatarBryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: default avatarBryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: default avatarMichael Cyr <mikecyr@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Cyr <mikecyr@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent dff0ca9e

drivers/target/target_core_transport.c

+6 −1
Original line number Diff line number Diff line
@@ -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);

}

include/target/target_core_base.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

};



/*