From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nicholas A. Bellinger" Subject: [PATCH 2/2] tcm_fc: Generate TASK_SET_FULL status for response failures Date: Thu, 5 Jun 2014 23:30:02 +0000 Message-ID: <1402011002-20771-3-git-send-email-nab@daterainc.com> References: <1402011002-20771-1-git-send-email-nab@daterainc.com> Return-path: Received: from mail-ob0-f182.google.com ([209.85.214.182]:41328 "EHLO mail-ob0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751739AbaFEXzL (ORCPT ); Thu, 5 Jun 2014 19:55:11 -0400 Received: by mail-ob0-f182.google.com with SMTP id wn1so1922824obc.27 for ; Thu, 05 Jun 2014 16:55:10 -0700 (PDT) In-Reply-To: <1402011002-20771-1-git-send-email-nab@daterainc.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: target-devel Cc: linux-scsi , fcoe-devel , Nicholas Bellinger , Vasu Dev , Jun Wu 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); + /* + * 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