From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vasu Dev Subject: Re: [PATCH 2/2] tcm_fc: Generate TASK_SET_FULL status for response failures Date: Fri, 06 Jun 2014 14:03:25 -0700 Message-ID: <1402088605.5752.106.camel@vi-devel> References: <1402011002-20771-1-git-send-email-nab@daterainc.com> <1402011002-20771-3-git-send-email-nab@daterainc.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1402011002-20771-3-git-send-email-nab-PEzghdH756F8UrSeD/g0lQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: fcoe-devel-bounces-s9riP+hp16TNLxjTenLetw@public.gmane.org Sender: fcoe-devel-bounces-s9riP+hp16TNLxjTenLetw@public.gmane.org To: "Nicholas A. Bellinger" Cc: fcoe-devel , target-devel , linux-scsi List-Id: linux-scsi@vger.kernel.org On Thu, 2014-06-05 at 23:30 +0000, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger > > 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 > Cc: Vasu Dev > Cc: Jun Wu > Signed-off-by: Nicholas Bellinger > --- > 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. > + /* > + * 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