From patchwork Tue Sep 29 10:47:30 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 7285191 Return-Path: X-Original-To: patchwork-linux-scsi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 96106BF90C for ; Tue, 29 Sep 2015 10:48:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A256E206DC for ; Tue, 29 Sep 2015 10:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91568206D8 for ; Tue, 29 Sep 2015 10:48:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934693AbbI2Ksk (ORCPT ); Tue, 29 Sep 2015 06:48:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:42105 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934710AbbI2KsF (ORCPT ); Tue, 29 Sep 2015 06:48:05 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E159475038; Tue, 29 Sep 2015 10:47:48 +0000 (UTC) From: Hannes Reinecke To: James Bottomley Cc: linux-scsi@vger.kernel.org, Christoph Hellwig , Bart van Assche , Ewan Milne , "Martin K. Petersen" , Hannes Reinecke Subject: [PATCH 28/36] scsi_dh_alua: Recheck state on unit attention Date: Tue, 29 Sep 2015 12:47:30 +0200 Message-Id: <1443523658-87622-29-git-send-email-hare@suse.de> X-Mailer: git-send-email 1.8.5.6 In-Reply-To: <1443523658-87622-1-git-send-email-hare@suse.de> References: <1443523658-87622-1-git-send-email-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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 When we receive a unit attention code of 'ALUA state changed' we should recheck the state, as it might be due to an implicit ALUA state transition. This allows us to return NEEDS_RETRY instead of ADD_TO_MLQUEUE, allowing to terminate the retries after a certain time. At the same time a workqueue item might already be queued, which should be started immediately to avoid any delays. Signed-off-by: Hannes Reinecke --- drivers/scsi/device_handler/scsi_dh_alua.c | 58 ++++++++++++++++++++++++------ 1 file changed, 47 insertions(+), 11 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 1b7153f..21f0d20 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -117,7 +117,8 @@ struct alua_queue_data { static void alua_rtpg_work(struct work_struct *work); static void alua_rtpg_queue(struct alua_port_group *pg, struct scsi_device *sdev, - struct alua_queue_data *qdata); + struct alua_queue_data *qdata, bool force); +static void alua_check(struct scsi_device *sdev, bool force); static void release_port_group(struct kref *kref) { @@ -387,7 +388,7 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, rcu_assign_pointer(h->pg, pg); pg_found = true; } - alua_rtpg_queue(h->pg, sdev, NULL); + alua_rtpg_queue(h->pg, sdev, NULL, true); spin_unlock(&h->pg_lock); if (pg_found) @@ -428,18 +429,24 @@ static int alua_check_sense(struct scsi_device *sdev, { switch (sense_hdr->sense_key) { case NOT_READY: - if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) + if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) { /* * LUN Not Accessible - ALUA state transition */ - return ADD_TO_MLQUEUE; + alua_check(sdev, false); + return NEEDS_RETRY; + } break; case UNIT_ATTENTION: - if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) + if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) { /* - * Power On, Reset, or Bus Device Reset, just retry. + * Power On, Reset, or Bus Device Reset. + * Might have obscured a state transition, + * so schedule a recheck. */ + alua_check(sdev, true); return ADD_TO_MLQUEUE; + } if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04) /* * Device internal reset @@ -450,16 +457,20 @@ static int alua_check_sense(struct scsi_device *sdev, * Mode Parameters Changed */ return ADD_TO_MLQUEUE; - if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) { /* * ALUA state changed */ + alua_check(sdev, true); return ADD_TO_MLQUEUE; - if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) + } + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) { /* * Implicit ALUA state transition failed */ + alua_check(sdev, true); return ADD_TO_MLQUEUE; + } if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03) /* * Inquiry data has changed @@ -775,7 +786,7 @@ static void alua_rtpg_work(struct work_struct *work) static void alua_rtpg_queue(struct alua_port_group *pg, struct scsi_device *sdev, - struct alua_queue_data *qdata) + struct alua_queue_data *qdata, bool force) { int start_queue = 0; unsigned long flags; @@ -795,7 +806,9 @@ static void alua_rtpg_queue(struct alua_port_group *pg, pg->rtpg_sdev = sdev; scsi_device_get(sdev); start_queue = 1; - } + } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) + start_queue = 1; + spin_unlock_irqrestore(&pg->lock, flags); if (start_queue && @@ -910,7 +923,7 @@ static int alua_activate(struct scsi_device *sdev, kref_get(&pg->kref); rcu_read_unlock(); - alua_rtpg_queue(pg, sdev, qdata); + alua_rtpg_queue(pg, sdev, qdata, true); kref_put(&pg->kref, release_port_group); out: if (fn) @@ -919,6 +932,29 @@ out: } /* + * alua_check - check path status + * @sdev: device on the path to be checked + * + * Check the device status + */ +static void alua_check(struct scsi_device *sdev, bool force) +{ + struct alua_dh_data *h = sdev->handler_data; + struct alua_port_group *pg; + + rcu_read_lock(); + pg = rcu_dereference(h->pg); + if (!pg) { + rcu_read_unlock(); + return; + } + kref_get(&pg->kref); + rcu_read_unlock(); + alua_rtpg_queue(pg, sdev, NULL, force); + kref_put(&pg->kref, release_port_group); +} + +/* * alua_prep_fn - request callback * * Fail I/O to all paths not in state