From patchwork Wed Apr 15 14:17:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11491349 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D4F9214B4 for ; Wed, 15 Apr 2020 14:18:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C66AA20767 for ; Wed, 15 Apr 2020 14:18:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2506393AbgDOOSD (ORCPT ); Wed, 15 Apr 2020 10:18:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:43912 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2506374AbgDOORy (ORCPT ); Wed, 15 Apr 2020 10:17:54 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E4A9AAA7C; Wed, 15 Apr 2020 14:17:52 +0000 (UTC) From: Oliver Neukum To: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [PATCH 1/2] UAS: no use logging any details in case of ENODEV Date: Wed, 15 Apr 2020 16:17:49 +0200 Message-Id: <20200415141750.811-1-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Once a device is gone, the internal state does not matter anymore. There is no need to spam the logs. Signed-off-by: Oliver Neukum Fixes: 326349f824619 ("uas: add dead request list") --- drivers/usb/storage/uas.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c index 3670fda02c34..08503e3507bf 100644 --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -190,6 +190,9 @@ static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix, struct uas_cmd_info *ci = (void *)&cmnd->SCp; struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp; + if (status == -ENODEV) /* too late */ + return; + scmd_printk(KERN_INFO, cmnd, "%s %d uas-tag %d inflight:%s%s%s%s%s%s%s%s%s%s%s%s ", prefix, status, cmdinfo->uas_tag, From patchwork Wed Apr 15 14:17:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11491347 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6BCF917EF for ; Wed, 15 Apr 2020 14:18:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E8A320857 for ; Wed, 15 Apr 2020 14:18:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2506388AbgDOOSC (ORCPT ); Wed, 15 Apr 2020 10:18:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:43918 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2506384AbgDOORz (ORCPT ); Wed, 15 Apr 2020 10:17:55 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 1CE96AB3D; Wed, 15 Apr 2020 14:17:53 +0000 (UTC) From: Oliver Neukum To: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [PATCH 2/2] UAS: fix deadlock in error handling and PM flushing work Date: Wed, 15 Apr 2020 16:17:50 +0200 Message-Id: <20200415141750.811-2-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200415141750.811-1-oneukum@suse.com> References: <20200415141750.811-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org A SCSI error handler and block runtime PM must not allocate memory with GFP_KERNEL. Furthermore they must not wait for tasks allocating memory with GFP_KERNEL. That means that they cannot share a workqueue with arbitrary tasks. Fix this for UAS using a private workqueue. Signed-off-by: Oliver Neukum Fixes: f9dc024a2da1f ("uas: pre_reset and suspend: Fix a few races") --- drivers/usb/storage/uas.c | 43 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 3 deletions(-) diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c index 08503e3507bf..d592071119ba 100644 --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -81,6 +81,19 @@ static void uas_free_streams(struct uas_dev_info *devinfo); static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix, int status); +/* + * This driver needs its own workqueue, as we need to control memory allocation. + * + * In the course of error handling and power management uas_wait_for_pending_cmnds() + * needs to flush pending work items. In these contexts we cannot allocate memory + * by doing block IO as we would deadlock. For the same reason we cannot wait + * for anything allocating memory not heeding these constraints. + * + * So we have to control all work items that can be on the workqueue we flush. + * Hence we cannot share a queue and need our own. + */ +static struct workqueue_struct *workqueue; + static void uas_do_work(struct work_struct *work) { struct uas_dev_info *devinfo = @@ -109,7 +122,7 @@ static void uas_do_work(struct work_struct *work) if (!err) cmdinfo->state &= ~IS_IN_WORK_LIST; else - schedule_work(&devinfo->work); + queue_work(workqueue, &devinfo->work); } out: spin_unlock_irqrestore(&devinfo->lock, flags); @@ -134,7 +147,7 @@ static void uas_add_work(struct uas_cmd_info *cmdinfo) lockdep_assert_held(&devinfo->lock); cmdinfo->state |= IS_IN_WORK_LIST; - schedule_work(&devinfo->work); + queue_work(workqueue, &devinfo->work); } static void uas_zap_pending(struct uas_dev_info *devinfo, int result) @@ -1229,7 +1242,31 @@ static struct usb_driver uas_driver = { .id_table = uas_usb_ids, }; -module_usb_driver(uas_driver); +static int __init uas_init(void) +{ + int rv; + + workqueue = alloc_workqueue("uas", WQ_MEM_RECLAIM, 0); + if (!workqueue) + return -ENOMEM; + + rv = usb_register(&uas_driver); + if (rv) { + destroy_workqueue(workqueue); + return -ENOMEM; + } + + return 0; +} + +static void __exit uas_exit(void) +{ + usb_deregister(&uas_driver); + destroy_workqueue(workqueue); +} + +module_init(uas_init); +module_exit(uas_exit); MODULE_LICENSE("GPL"); MODULE_IMPORT_NS(USB_STORAGE);