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Commit b3e5fe16 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

tcm_fc: Generate TASK_SET_FULL status for DataIN failures 



This patch changes ft_queue_data_in() to set SAM_STAT_TASK_SET_FULL
status upon a lport->tt.seq_send() failure, where it will now stop
sending subsequent DataIN, and immediately attempt to send the
response with exception status.

Sending a response with SAM_STAT_TASK_SET_FULL status is useful in
order to signal the initiator that it should try to reduce it's
current queue_depth, to lower the number of outstanding I/Os on
the wire.

Also, add a check to skip sending DataIN if TASK_SET_FULL status
has already been set due to a response lport->tt.seq_send()
failure, that has asked target-core to requeue a response.

Reported-by: default avatarVasu Dev <vasu.dev@linux.intel.com>
Reviewed-by: default avatarVasu Dev <vasu.dev@linux.intel.com>
Cc: Jun Wu <jwu@stormojo.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 1d2b60a5

drivers/target/tcm_fc/tfc_io.c

+15 −2
Original line number Diff line number Diff line
@@ -82,6 +82,10 @@ int ft_queue_data_in(struct se_cmd *se_cmd) 


	if (cmd->aborted)

		return 0;



	if (se_cmd->scsi_status == SAM_STAT_TASK_SET_FULL)

		goto queue_status;



	ep = fc_seq_exch(cmd->seq);

	lport = ep->lp;

	cmd->seq = lport->tt.seq_start_next(cmd->seq);
@@ -178,14 +182,23 @@ int ft_queue_data_in(struct se_cmd *se_cmd) 
			       FC_TYPE_FCP, f_ctl, fh_off);

		error = lport->tt.seq_send(lport, seq, fp);

		if (error) {

			/* XXX For now, initiator will retry */

			pr_err_ratelimited("%s: Failed to send frame %p, "

			pr_info_ratelimited("%s: Failed to send frame %p, "

						"xid <0x%x>, remaining %zu, "

						"lso_max <0x%x>\n",

						__func__, fp, ep->xid,

						remaining, lport->lso_max);

			/*

			 * Go ahead and set TASK_SET_FULL status ignoring the

			 * rest of the DataIN, and immediately attempt to

			 * send the response via ft_queue_status() in order

			 * to notify the initiator that it should reduce it's

			 * per LUN queue_depth.

			 */

			se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;

			break;

		}

	}

queue_status:

	return ft_queue_status(se_cmd);

}