From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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 <vasu.dev@xxxxxxxxxxxxxxx>
Cc: Vasu Dev <vasu.dev@xxxxxxxxxxxxxxx>
Cc: Jun Wu <jwu@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/tcm_fc/tfc_io.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/target/tcm_fc/tfc_io.c b/drivers/target/tcm_fc/tfc_io.c
index e415af3..140659f 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 +182,22 @@ 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, "
"xid <0x%x>, remaining %zu, "
"lso_max <0x%x>\n",
__func__, fp, ep->xid,
remaining, lport->lso_max);
+ /*
+ * Generate a TASK_SET_FULL status to notify the
+ * initiator to reduce it's queue_depth, ignoring
+ * the rest of the data-in and immediately attempt
+ * to send the response.
+ */
+ se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
+ break;
}
}
+queue_status:
return ft_queue_status(se_cmd);
}
--
1.7.10.4
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