From b3e5fe1688b998ba5287a68667ef7cc568739e44 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Thu, 5 Jun 2014 16:27:53 -0700 Subject: [PATCH] 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: Vasu Dev Reviewed-by: Vasu Dev Cc: Jun Wu Signed-off-by: Nicholas Bellinger --- drivers/target/tcm_fc/tfc_io.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/target/tcm_fc/tfc_io.c b/drivers/target/tcm_fc/tfc_io.c index e415af32115a..97b486c3dda1 100644 --- a/drivers/target/tcm_fc/tfc_io.c +++ b/drivers/target/tcm_fc/tfc_io.c @@ -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); } -- 2.20.1