From patchwork Tue Mar 29 14:42:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurence Oberman X-Patchwork-Id: 8687801 Return-Path: X-Original-To: patchwork-linux-scsi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 2A34B9F3D1 for ; Tue, 29 Mar 2016 14:42:45 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 28CEA202C8 for ; Tue, 29 Mar 2016 14:42:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0565F20251 for ; Tue, 29 Mar 2016 14:42:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757061AbcC2Omm (ORCPT ); Tue, 29 Mar 2016 10:42:42 -0400 Received: from mx4-phx2.redhat.com ([209.132.183.25]:49292 "EHLO mx4-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756204AbcC2Omm (ORCPT ); Tue, 29 Mar 2016 10:42:42 -0400 Received: from zmail22.collab.prod.int.phx2.redhat.com (zmail22.collab.prod.int.phx2.redhat.com [10.5.83.26]) by mx4-phx2.redhat.com (8.13.8/8.13.8) with ESMTP id u2TEgc10027900; Tue, 29 Mar 2016 10:42:39 -0400 Date: Tue, 29 Mar 2016 10:42:38 -0400 (EDT) From: Laurence Oberman To: Bart Van Assche , linux-scsi@vger.kernel.org Message-ID: <2025450295.25603731.1459262558755.JavaMail.zimbra@redhat.com> In-Reply-To: <1094927874.25583811.1459257571936.JavaMail.zimbra@redhat.com> Subject: tcm_qla2xxx Add SCSI command jammer/discard capabilty to the tcm_qla2xxx module - revision3 MIME-Version: 1.0 X-Originating-IP: [10.18.49.29] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF38 (Linux)/8.0.6_GA_5922) Thread-Topic: tcm_qla2xxx Add SCSI command jammer/discard capabilty to the tcm_qla2xxx module - revision3 Thread-Index: ijRl2r2idYjwugcXD6icxp9GJCosIg== Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hello Bart, I have been using this jammer functionality to continue testing the SCSI F/C drivers and recovery for over a year now. Any chance you would agree to ack this so I can get it in now. I last posted to the list last March and it was not picked up. I did look into moving this to upper layers but I find I use it primarily for fiber channel target testing. Attempting to add this functionality to upper layers led to complexities and this is very solid. This Patch diff against 4.5 I use target LIO for all my storage array test targets and customer problem resolution here at Red Hat. This patch resulted from a requirement to mimic behavior of an expensive hardware jammer for a customer. I have used this for some time with good success to simulate and reproduce latency and slow drain fabric issues and for testing and validating error handling behavior in the Emulex, Qlogic and other F/C drivers. Works by checking new parameter jam_host if its >= 0 and matches vha->host_no , jamming is enabled when jam_host >=0 If parameter set to -1 (default) no jamming is enabled. Tested by: Laurence Oberman Signed-off-by: Laurence Oberman Laurence Oberman Principal Software Maintenance Engineer Red Hat Global Support Services --- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff -Nurp linux-4.5.orig/Documentation/scsi/tcm_qla2xxx.txt linux-4.5/Documentation/scsi/tcm_qla2xxx.txt --- linux-4.5.orig/Documentation/scsi/tcm_qla2xxx.txt 1969-12-31 19:00:00.000000000 -0500 +++ linux-4.5/Documentation/scsi/tcm_qla2xxx.txt 2016-03-29 10:08:57.455761389 -0400 @@ -0,0 +1,31 @@ +tcm_qla2xxx jammer parameter usage +---------------------------------- +There is now a new module parameter added to the tcm_qla2xx module +parm: jam_host:Host to jam >=0 Enable jammer (int) + +Use this parameter to control the discarding of SCSI commands to a selected +host. +This may be useful for testing error handling and simulating slow drain +and other fabric issues. + +Any value >=0 that matches a fc_host # will discard the commands for that host. +Reset back to -1 to stop the jamming. + +Enable host 6 to be jammed +echo 6 > /sys/module/tcm_qla2xxx/parameters/jam_host + +Disable jamming on host 6 +echo -1 > /sys/module/tcm_qla2xxx/parameters/jam_host + +Usage example script: + +#!/bin/bash +sleep_time=120 ### Time to jam for +echo 6 > /sys/module/tcm_qla2xxx/parameters/jam_host +host=`cat /sys/module/tcm_qla2xxx/parameters/jam_host` +echo "We start to discard commands on SCSI host $host" +logger "Jammer started" +sleep $sleep_time +echo -1 > /sys/module/tcm_qla2xxx/parameters/jam_host +echo "We stopped the jammer" +logger "Jammer stopped" diff -Nurp linux-4.5.orig/drivers/scsi/qla2xxx/tcm_qla2xxx.c linux-4.5/drivers/scsi/qla2xxx/tcm_qla2xxx.c --- linux-4.5.orig/drivers/scsi/qla2xxx/tcm_qla2xxx.c 2016-03-14 00:28:54.000000000 -0400 +++ linux-4.5/drivers/scsi/qla2xxx/tcm_qla2xxx.c 2016-03-29 10:10:09.677298099 -0400 @@ -48,6 +48,10 @@ #include "qla_target.h" #include "tcm_qla2xxx.h" +int jam_host = -1; +module_param(jam_host, int, 0644); +MODULE_PARM_DESC(jam_host, "Host to jam >=0 Enable jammer"); + static struct workqueue_struct *tcm_qla2xxx_free_wq; static struct workqueue_struct *tcm_qla2xxx_cmd_wq; @@ -477,6 +481,11 @@ static int tcm_qla2xxx_handle_cmd(scsi_q return -EINVAL; } + if (unlikely(vha->host_no == jam_host)) { + /* return, and dont run target_submit_cmd,discarding command */ + return 0; + } + cmd->vha->tgt_counters.qla_core_sbt_cmd++; return target_submit_cmd(se_cmd, se_sess, cdb, &cmd->sense_buffer[0], cmd->unpacked_lun, data_length, fcp_task_attr, @@ -1967,6 +1976,7 @@ static void tcm_qla2xxx_deregister_confi static int __init tcm_qla2xxx_init(void) { int ret; + jam_host = -1; ret = tcm_qla2xxx_register_configfs(); if (ret < 0)