From patchwork Fri Mar 16 17:40:16 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 10289713 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9B67C601A0 for ; Fri, 16 Mar 2018 17:40:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8756A28FD3 for ; Fri, 16 Mar 2018 17:40:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7ADF729004; Fri, 16 Mar 2018 17:40:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DE0F828FD3 for ; Fri, 16 Mar 2018 17:40:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752130AbeCPRkS (ORCPT ); Fri, 16 Mar 2018 13:40:18 -0400 Received: from esa5.hgst.iphmx.com ([216.71.153.144]:54408 "EHLO esa5.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751576AbeCPRkR (ORCPT ); Fri, 16 Mar 2018 13:40:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1521222017; x=1552758017; h=from:to:cc:subject:date:message-id; bh=mKrT1JqpNpglxhLswLZm5ENGbT4YEc9zF3uA3u91dOI=; b=SgrSSg93Bcds4LcHr+DV0D5v16AgX4BS+46w/6I2rjf4tzr+znRXSKVB BUN83qpQzlvgZJX/HZ6HmDqyarxg+krZqf5vzIc1HS8ZBuUshGr+bmK00 OVqLqdzK3tZGrj+DLMM2Srzsi7Hc9T8XVcyFQU4LPqIXCFiCEh3NTAs4x CjV+MSnYvqBUM3kBOA24yRbaDLkdeqJ6H9kKPk+egZlQDYcTwiqCy5FlD QCV25T5GB7IA8El22GkLYuB+YKacJLhHePhSBX2ujMfD1+SpjcFaZxoJG u9BdcN4Me8jEj9KCK3kOeCTc15rfk6AwxrgHebKOnA1x7tlOUttZse/mc w==; X-IronPort-AV: E=Sophos;i="5.48,316,1517846400"; d="scan'208";a="73818841" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 17 Mar 2018 01:40:17 +0800 Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP; 16 Mar 2018 10:33:12 -0700 Received: from thinkpad-bart.sdcorp.global.sandisk.com (HELO thinkpad-bart.int.fusionio.com) ([10.11.171.236]) by uls-op-cesaip01.wdc.com with ESMTP; 16 Mar 2018 10:40:17 -0700 From: Bart Van Assche To: "Martin K . Petersen" , "James E . J . Bottomley" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Hannes Reinecke , Johannes Thumshirn Subject: [PATCH v2] scsi: Avoid that .queuecommand() gets called for a quiesced SCSI device Date: Fri, 16 Mar 2018 10:40:16 -0700 Message-Id: <20180316174016.5127-1-bart.vanassche@wdc.com> X-Mailer: git-send-email 2.16.2 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Several SCSI transport and LLD drivers surround code that does not tolerate concurrent calls of .queuecommand() with scsi_target_block() / scsi_target_unblock(). These last two functions use blk_mq_quiesce_queue() / blk_mq_unquiesce_queue() for scsi-mq request queues to prevent concurrent .queuecommand() calls. However, that is not sufficient to prevent .queuecommand() calls from scsi_send_eh_cmnd(). Hence surround the .queuecommand() call from the SCSI error handler with code that avoids that .queuecommand() gets called in the quiesced state. Notes: - Converting the .queuecommand() call in scsi_send_eh_cmnd() into code that calls blk_get_request() + blk_execute_rq() is not an option since scsi_send_eh_cmnd() must be able to make forward progress even if all requests are allocated. - Converting the .queuecommand() call in scsi_send_eh_cmnd() into a blk_execute_rq() or blk_mq_requeue_request() call is not an option either because that would require to change every individual function in the I/O path. Each function in the I/O path would have to be modified such that it handles requests received from the block layer core and request received from the SCSI EH differently. Since struct scsi_cmnd is not initialized by the block layer for filesystem requests, it is not possible to determine in scsi_queue_rq() whether or not a request has been submitted by the SCSI EH without modifying the block layer. Signed-off-by: Bart Van Assche Cc: Hannes Reinecke Cc: Johannes Thumshirn --- Changes compared to v1: - As requested by James, removed the wait queue again that was added to the SCSI device structure. drivers/scsi/scsi_error.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 946039117bf4..71d7d2b893ab 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1039,7 +1039,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, struct scsi_device *sdev = scmd->device; struct Scsi_Host *shost = sdev->host; DECLARE_COMPLETION_ONSTACK(done); - unsigned long timeleft = timeout; + unsigned long timeleft = timeout, delay; struct scsi_eh_save ses; const unsigned long stall_for = msecs_to_jiffies(100); int rtn; @@ -1050,7 +1050,22 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, scsi_log_send(scmd); scmd->scsi_done = scsi_eh_done; - rtn = shost->hostt->queuecommand(shost, scmd); + mutex_lock(&sdev->state_mutex); + while (sdev->sdev_state == SDEV_QUIESCE && timeleft > 0) { + mutex_unlock(&sdev->state_mutex); + SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev, + "%s: state %d <> %d\n", __func__, sdev->sdev_state, + SDEV_QUIESCE)); + delay = min(timeleft, stall_for); + timeleft -= delay; + msleep(jiffies_to_msecs(delay)); + mutex_lock(&sdev->state_mutex); + } + if (sdev->sdev_state != SDEV_QUIESCE) + rtn = shost->hostt->queuecommand(shost, scmd); + else + rtn = SCSI_MLQUEUE_DEVICE_BUSY; + mutex_unlock(&sdev->state_mutex); if (rtn) { if (timeleft > stall_for) { scsi_eh_restore_cmnd(scmd, &ses);