On Fri, 2014-06-06 at 14:03 -0700, Vasu Dev wrote:
> On Thu, 2014-06-05 at 23:30 +0000, Nicholas A. Bellinger wrote:
> > 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);
>
> May be should be pr_info_ratelimited since this is not really error and
> IO could get aborted due to timeouts in any setups or stressed
> workloads.
<nod>, changing this to pr_info_ratelimited and doing the same in
ft_queue_data_in() well.
>
> > + /*
> > + * 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;
> > }
>
> Reviewed-by: Vasu Dev <vasu.dev@xxxxxxxxx>
>
Thanks Vasu!
--nab
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