From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch changes ft_queue_status() to set SAM_STAT_TASK_SET_FULL
status upon lport->tt.seq_send( failure, and return -EAGAIN to notify
target-core to attempt to requeue the response.
It also does the same for a fc_frame_alloc() failures, 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.
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_cmd.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index f5fd515..5585038 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -128,6 +128,7 @@ int ft_queue_status(struct se_cmd *se_cmd)
struct fc_lport *lport;
struct fc_exch *ep;
size_t len;
+ int rc;
if (cmd->aborted)
return 0;
@@ -137,9 +138,10 @@ int ft_queue_status(struct se_cmd *se_cmd)
len = sizeof(*fcp) + se_cmd->scsi_sense_length;
fp = fc_frame_alloc(lport, len);
if (!fp) {
- /* XXX shouldn't just drop it - requeue and retry? */
- return 0;
+ se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
+ return -ENOMEM;
}
+
fcp = fc_frame_payload_get(fp, len);
memset(fcp, 0, len);
fcp->resp.fr_status = se_cmd->scsi_status;
@@ -170,7 +172,18 @@ int ft_queue_status(struct se_cmd *se_cmd)
fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ, 0);
- lport->tt.seq_send(lport, cmd->seq, fp);
+ rc = lport->tt.seq_send(lport, cmd->seq, fp);
+ if (rc) {
+ pr_err_ratelimited("%s: Failed to send response frame %p, "
+ "xid <0x%x>\n", __func__, fp, ep->xid);
+ /*
+ * Generate a TASK_SET_FULL status to notify the initiator
+ * to reduce it's queue_depth after the se_cmd response has
+ * been re-queued by target-core.
+ */
+ se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
+ return -ENOMEM;
+ }
lport->tt.exch_done(cmd->seq);
return 0;
}
--
1.7.10.4
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