From patchwork Wed Oct 18 07:14:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 10013815 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 435F460211 for ; Wed, 18 Oct 2017 07:14:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 363C3285DB for ; Wed, 18 Oct 2017 07:14:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 29DD1285E5; Wed, 18 Oct 2017 07:14:26 +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 BCDE9285DB for ; Wed, 18 Oct 2017 07:14:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761621AbdJRHOX (ORCPT ); Wed, 18 Oct 2017 03:14:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60040 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758347AbdJRHOW (ORCPT ); Wed, 18 Oct 2017 03:14:22 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5434215557; Wed, 18 Oct 2017 07:14:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5434215557 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mchristi@redhat.com Received: from rh2.redhat.com (ovpn-120-106.rdu2.redhat.com [10.10.120.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9991D7BA36; Wed, 18 Oct 2017 07:14:21 +0000 (UTC) From: Mike Christie To: lixiubo@cmss.chinamobile.com, target-devel@vger.kernel.org, nab@linux-iscsi.org Cc: Mike Christie Subject: [PATCH 05/17] tcmu: remove commands_lock Date: Wed, 18 Oct 2017 02:14:00 -0500 Message-Id: <1508310852-15366-6-git-send-email-mchristi@redhat.com> In-Reply-To: <1508310852-15366-1-git-send-email-mchristi@redhat.com> References: <1508310852-15366-1-git-send-email-mchristi@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 18 Oct 2017 07:14:22 +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 No need for the commands_lock. The cmdr_lock is already held during idr addition and deletion, so just grab it during traversal. Note: This also fixes 2 issues. There was no reason to use spin_lock_irq. We only were locking against the submitting, completion and timer context. The first two are done in process context (even though tcmu_irqcontrol is named irq it is run from the write() calls context) and the timer was in softirq, so we just needed to do _bh locking. We should have been using either one tcmu_handle_completions to prevent the case where tcmu_handle_completions could be interrupted a timer softirq while the commands_lock is held. Signed-off-by: Mike Christie --- drivers/target/target_core_user.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 40a9cf6..a222d15 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -141,7 +141,6 @@ struct tcmu_dev { struct radix_tree_root data_blocks; struct idr commands; - spinlock_t commands_lock; struct timer_list timeout; unsigned int cmd_time_out; @@ -1076,10 +1075,7 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev) } WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD); - spin_lock(&udev->commands_lock); cmd = idr_remove(&udev->commands, entry->hdr.cmd_id); - spin_unlock(&udev->commands_lock); - if (!cmd) { pr_err("cmd_id not found, ring is broken\n"); set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags); @@ -1175,7 +1171,6 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) INIT_LIST_HEAD(&udev->timedout_entry); idr_init(&udev->commands); - spin_lock_init(&udev->commands_lock); setup_timer(&udev->timeout, tcmu_device_timedout, (unsigned long)udev); @@ -1404,16 +1399,14 @@ static void tcmu_dev_kref_release(struct kref *kref) spin_unlock_bh(&timed_out_udevs_lock); /* Upper layer should drain all requests before calling this */ - spin_lock_irq(&udev->commands_lock); + mutex_lock(&udev->cmdr_lock); idr_for_each_entry(&udev->commands, cmd, i) { if (tcmu_check_and_free_pending_cmd(cmd) != 0) all_expired = false; } idr_destroy(&udev->commands); - spin_unlock_irq(&udev->commands_lock); WARN_ON(!all_expired); - mutex_lock(&udev->cmdr_lock); tcmu_blocks_release(&udev->data_blocks, 0, udev->dbi_max + 1); mutex_unlock(&udev->cmdr_lock); @@ -2066,9 +2059,9 @@ static void check_timedout_devices(void) list_del_init(&udev->timedout_entry); spin_unlock_bh(&timed_out_udevs_lock); - spin_lock(&udev->commands_lock); + mutex_lock(&udev->cmdr_lock); idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL); - spin_unlock(&udev->commands_lock); + mutex_unlock(&udev->cmdr_lock); spin_lock_bh(&timed_out_udevs_lock); }