From patchwork Wed Oct 18 07:14:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Christie X-Patchwork-Id: 10013827 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 29B3D60211 for ; Wed, 18 Oct 2017 07:14:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1CA12285DB for ; Wed, 18 Oct 2017 07:14:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1193328708; Wed, 18 Oct 2017 07:14:31 +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 C072D285DB for ; Wed, 18 Oct 2017 07:14:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761716AbdJRHO3 (ORCPT ); Wed, 18 Oct 2017 03:14:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55026 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761951AbdJRHO0 (ORCPT ); Wed, 18 Oct 2017 03:14:26 -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 09B3F7EA8C; Wed, 18 Oct 2017 07:14:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 09B3F7EA8C Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.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 4EDB27BA36; Wed, 18 Oct 2017 07:14:25 +0000 (UTC) From: Mike Christie To: lixiubo@cmss.chinamobile.com, target-devel@vger.kernel.org, nab@linux-iscsi.org Cc: Mike Christie Subject: [PATCH 09/17] tcmu: release blocks for partially setup cmds Date: Wed, 18 Oct 2017 02:14:04 -0500 Message-Id: <1508310852-15366-10-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 [10.5.110.28]); Wed, 18 Oct 2017 07:14:26 +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 If we cannot setup a cmd because we run out of ring space or global pages release the blocks before sleeping. This prevents a deadlock where dev0 has waiting_blocks set and needs N blocks, but dev1 to devX have each allocated N / X blocks and also hit the global block limit so they went to sleep. find_free_blocks is not able to take the sleeping dev's blocks becaause their waiting_blocks is set and even if it was not the block returned by find_last_bit could equal dbi_max. The latter will probably never happen because DATA_BLOCK_BITS is so high but in the next patches DATA_BLOCK_BITS and TCMU_GLOBAL_MAX_BLOCKS will be settable so it might be lower and could happen. Signed-off-by: Mike Christie --- drivers/target/target_core_user.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 8a22d60..b5cdbeb 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -841,6 +841,13 @@ tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) int ret; DEFINE_WAIT(__wait); + /* + * Don't leave commands partially setup because the unmap + * thread might need the blocks to make forward progress. + */ + tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur); + tcmu_cmd_reset_dbi_cur(tcmu_cmd); + prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE); pr_debug("sleeping for ring space\n");