From patchwork Wed Oct 25 16:47:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 10026991 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 EED2A60375 for ; Wed, 25 Oct 2017 16:47:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E030728BEC for ; Wed, 25 Oct 2017 16:47:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D50F528BEE; Wed, 25 Oct 2017 16:47:47 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI 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 61A4628BEC for ; Wed, 25 Oct 2017 16:47:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751958AbdJYQrr (ORCPT ); Wed, 25 Oct 2017 12:47:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57378 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751920AbdJYQrq (ORCPT ); Wed, 25 Oct 2017 12:47:46 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4CDC9B653; Wed, 25 Oct 2017 16:47:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 4CDC9B653 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mchristi@redhat.com Received: from rh2.redhat.com (ovpn-124-200.rdu2.redhat.com [10.10.124.200]) by smtp.corp.redhat.com (Postfix) with ESMTP id 990E38B15B; Wed, 25 Oct 2017 16:47:45 +0000 (UTC) From: Mike Christie To: target-devel@vger.kernel.org, nab@linux-iscsi.org Cc: Mike Christie Subject: [PATCH 07/20] tcmu: move expired command completion to unmap thread Date: Wed, 25 Oct 2017 11:47:17 -0500 Message-Id: <1508950050-10120-8-git-send-email-mchristi@redhat.com> In-Reply-To: <1508950050-10120-1-git-send-email-mchristi@redhat.com> References: <1508950050-10120-1-git-send-email-mchristi@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 25 Oct 2017 16:47:46 +0000 (UTC) Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This moves the expired command completion handling to the unmap thread, so the next patch can use a mutex in tcmu_check_expired_cmd. Notes: tcmu_device_timedout's use of spin_lock_irq was not needed. The commands_lock is used between thread context (tcmu_queue_cmd_ring and tcmu_irqcontrol) and timer/bh context. In the timer/bh context bhs are disabled, so you need to use the _bh lock calls from the thread context callers. Signed-off-by: Mike Christie --- drivers/target/target_core_user.c | 62 ++++++++++++++++++++++++++++++++------- 1 file changed, 51 insertions(+), 11 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 4d45bb2..53a0446 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -145,6 +145,7 @@ struct tcmu_dev { struct timer_list timeout; unsigned int cmd_time_out; + struct list_head timedout_entry; spinlock_t nl_cmd_lock; struct tcmu_nl_cmd curr_nl_cmd; @@ -180,6 +181,10 @@ struct tcmu_cmd { static struct task_struct *unmap_thread; static wait_queue_head_t unmap_wait; + +static DEFINE_SPINLOCK(timed_out_udevs_lock); +static LIST_HEAD(timed_out_udevs); + /* * To avoid dead lock, the mutex locks order should always be: * @@ -1116,19 +1121,15 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) static void tcmu_device_timedout(unsigned long data) { struct tcmu_dev *udev = (struct tcmu_dev *)data; - unsigned long flags; - spin_lock_irqsave(&udev->commands_lock, flags); - idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); - spin_unlock_irqrestore(&udev->commands_lock, flags); + pr_debug("%s cmd timeout has expired\n", udev->name); - /* Try to wake up the ummap thread */ - wake_up(&unmap_wait); + spin_lock(&timed_out_udevs_lock); + if (list_empty(&udev->timedout_entry)) + list_add_tail(&udev->timedout_entry, &timed_out_udevs); + spin_unlock(&timed_out_udevs_lock); - /* - * We don't need to wakeup threads on wait_cmdr since they have their - * own timeout. - */ + wake_up(&unmap_wait); } static int tcmu_attach_hba(struct se_hba *hba, u32 host_id) @@ -1172,6 +1173,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) init_waitqueue_head(&udev->wait_cmdr); mutex_init(&udev->cmdr_lock); + INIT_LIST_HEAD(&udev->timedout_entry); idr_init(&udev->commands); spin_lock_init(&udev->commands_lock); @@ -1396,6 +1398,11 @@ static void tcmu_dev_kref_release(struct kref *kref) vfree(udev->mb_addr); udev->mb_addr = NULL; + spin_lock_bh(&timed_out_udevs_lock); + if (!list_empty(&udev->timedout_entry)) + list_del(&udev->timedout_entry); + spin_unlock_bh(&timed_out_udevs_lock); + /* Upper layer should drain all requests before calling this */ spin_lock_irq(&udev->commands_lock); idr_for_each_entry(&udev->commands, cmd, i) { @@ -2047,23 +2054,56 @@ static struct target_backend_ops tcmu_ops = { .tb_dev_attrib_attrs = NULL, }; +static void check_timedout_devices(void) +{ + struct tcmu_dev *udev, *tmp_dev; + LIST_HEAD(devs); + + spin_lock_bh(&timed_out_udevs_lock); + list_splice_init(&timed_out_udevs, &devs); + + list_for_each_entry_safe(udev, tmp_dev, &devs, timedout_entry) { + list_del_init(&udev->timedout_entry); + spin_unlock_bh(&timed_out_udevs_lock); + + spin_lock(&udev->commands_lock); + idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); + spin_unlock(&udev->commands_lock); + + spin_lock_bh(&timed_out_udevs_lock); + } + spin_unlock_bh(&timed_out_udevs_lock); +} + static int unmap_thread_fn(void *data) { struct tcmu_dev *udev, *tmp; loff_t off; uint32_t start, end, block; static uint32_t free_blocks; + bool has_timed_out_devs; while (!kthread_should_stop()) { DEFINE_WAIT(__wait); prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE); - schedule(); + + spin_lock_bh(&timed_out_udevs_lock); + has_timed_out_devs = true; + if (list_empty(&timed_out_udevs)) + has_timed_out_devs = false; + spin_unlock_bh(&timed_out_udevs_lock); + + if (!has_timed_out_devs) + schedule(); + finish_wait(&unmap_wait, &__wait); if (kthread_should_stop()) break; + check_timedout_devices(); + mutex_lock(&root_udev_mutex); list_for_each_entry(udev, &root_udev, node) { mutex_lock(&udev->cmdr_lock);