From patchwork Wed Mar 14 22:45:21 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: 10283699 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 61F6A602C2 for ; Wed, 14 Mar 2018 22:45:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 49A0E286EB for ; Wed, 14 Mar 2018 22:45:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3E2CF286F5; Wed, 14 Mar 2018 22:45:24 +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 795B7286EB for ; Wed, 14 Mar 2018 22:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751362AbeCNWpW (ORCPT ); Wed, 14 Mar 2018 18:45:22 -0400 Received: from esa5.hgst.iphmx.com ([216.71.153.144]:16275 "EHLO esa5.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289AbeCNWpW (ORCPT ); Wed, 14 Mar 2018 18:45:22 -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=1521067522; x=1552603522; h=from:to:cc:subject:date:message-id; bh=jr9R9NEULa9zSzBMA3cP1vyK8Lfa7naAnO2LOO6E1NI=; b=Vx765FT563NwBBpmXtMggnna0AMyJs81HR9+BWyw7UisC5eh6P8tUbm+ MynnnpnN95pfk3ZIyjHpvvhi9hfAffubs7An80L/K29n0Amx8jlNcO1bm UrCVvO93YbNc5gIifseZp0B58YVfxb51iX3TehO3zWwj5zL5PwnxL3mXa hXWLPncfj8BePfeQa78f9EbXVlJ1NX4U8s7dHuDVCdOxw7tqVgdBrFgIW RALQPRzENQBUkah9ThQWzBwucD+F35y+JiEKajDsqHbYTjAfIIUb6TZV4 8NzsTMoFpRokMxgfKeajAHO5q6GT3jZNQu016TBpi+0MWSHQh1hp8laYy g==; X-IronPort-AV: E=Sophos;i="5.48,307,1517846400"; d="scan'208";a="73671490" Received: from h199-255-45-14.hgst.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 15 Mar 2018 06:45:22 +0800 Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP; 14 Mar 2018 15:38:57 -0700 Received: from thinkpad-bart.sdcorp.global.sandisk.com (HELO thinkpad-bart.int.fusionio.com) ([10.11.171.236]) by uls-op-cesaip02.wdc.com with ESMTP; 14 Mar 2018 15:45:21 -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, resend] scsi: Avoid that .queuecommand() gets called for a quiesced SCSI device Date: Wed, 14 Mar 2018 15:45:21 -0700 Message-Id: <20180314224521.22409-1-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 --- drivers/scsi/scsi_error.c | 13 +++++++++++++ drivers/scsi/scsi_lib.c | 2 ++ drivers/scsi/scsi_scan.c | 1 + include/scsi/scsi_device.h | 1 + 4 files changed, 17 insertions(+) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 946039117bf4..cfc805851a2a 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1042,6 +1042,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, unsigned long timeleft = timeout; struct scsi_eh_save ses; const unsigned long stall_for = msecs_to_jiffies(100); + DEFINE_WAIT(wait); int rtn; retry: @@ -1050,7 +1051,19 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, scsi_log_send(scmd); scmd->scsi_done = scsi_eh_done; + mutex_lock(&sdev->state_mutex); + while (sdev->sdev_state == SDEV_QUIESCE) { + prepare_to_wait(&sdev->state_wq, &wait, TASK_INTERRUPTIBLE); + 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)); + schedule(); + mutex_lock(&sdev->state_mutex); + } + finish_wait(&sdev->state_wq, &wait); rtn = shost->hostt->queuecommand(shost, scmd); + mutex_unlock(&sdev->state_mutex); if (rtn) { if (timeleft > stall_for) { scsi_eh_restore_cmnd(scmd, &ses); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 1d83f29aee74..99741858b6da 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2757,6 +2757,7 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) } sdev->sdev_state = state; + wake_up_all(&sdev->state_wq); return 0; illegal: @@ -3216,6 +3217,7 @@ int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, default: return -EINVAL; } + wake_up_all(&sdev->state_wq); scsi_start_queue(sdev); return 0; diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 0880d975eed3..32439ca61c18 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -232,6 +232,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, sdev->id = starget->id; sdev->lun = lun; sdev->channel = starget->channel; + init_waitqueue_head(&sdev->state_wq); mutex_init(&sdev->state_mutex); sdev->sdev_state = SDEV_CREATED; INIT_LIST_HEAD(&sdev->siblings); diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 7ae177c8e399..eb9063202036 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -222,6 +222,7 @@ struct scsi_device { void *handler_data; unsigned char access_state; + struct wait_queue_head state_wq; struct mutex state_mutex; enum scsi_device_state sdev_state; struct task_struct *quiesced_by;