From patchwork Mon Jun 14 08:29:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 1491572 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=MtlVWOCD; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4G3Pmc2RLhz9sT6 for ; Mon, 14 Jun 2021 18:31:12 +1000 (AEST) Received: from localhost ([::1]:43060 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lshzy-0002fM-13 for incoming@patchwork.ozlabs.org; Mon, 14 Jun 2021 04:31:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44114) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lshyY-0002HZ-Hk for qemu-devel@nongnu.org; Mon, 14 Jun 2021 04:29:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:38636) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lshyW-0005pn-TJ for qemu-devel@nongnu.org; Mon, 14 Jun 2021 04:29:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623659380; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sq0zn2MR504VMOSmeUVt0uGq5nK0p95DRBi9lImC/S0=; b=MtlVWOCDWo1Zuto3qHxyRx5YAx+j92QTwKn3YZvzlxGVdq79L1Cnpp3nj40XqykiIzKaC6 blGceDnLpIVKrnnkNB3+W5Nb27SRn8OYnllL8CA2DKJYm7wtg5NZmgN15ULRXtfFbTEGpj N9k2Yp1luwz8+roQUFfwW4OCI/M3OuE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-358-AVlyBwNDNICK9xoAN4NGoA-1; Mon, 14 Jun 2021 04:29:38 -0400 X-MC-Unique: AVlyBwNDNICK9xoAN4NGoA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ED6A1107ACF6; Mon, 14 Jun 2021 08:29:37 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-49.ams2.redhat.com [10.36.113.49]) by smtp.corp.redhat.com (Postfix) with ESMTP id ECE6E5D9D3; Mon, 14 Jun 2021 08:29:35 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v5 1/6] blkdebug: refactor removal of a suspended request Date: Mon, 14 Jun 2021 10:29:26 +0200 Message-Id: <20210614082931.24925-2-eesposit@redhat.com> In-Reply-To: <20210614082931.24925-1-eesposit@redhat.com> References: <20210614082931.24925-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.199, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Emanuele Giuseppe Esposito , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Extract to a separate function. Do not rely on FOREACH_SAFE, which is only "safe" if the *current* node is removed---not if another node is removed. Instead, just walk the entire list from the beginning when asked to resume all suspended requests with a given tag. Co-developed-by: Paolo Bonzini Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake --- block/blkdebug.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/block/blkdebug.c b/block/blkdebug.c index 2c0b9b0ee8..5ccbfcab42 100644 --- a/block/blkdebug.c +++ b/block/blkdebug.c @@ -793,7 +793,6 @@ static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule) printf("blkdebug: Resuming request '%s'\n", r.tag); } - QLIST_REMOVE(&r, next); g_free(r.tag); } @@ -869,25 +868,40 @@ static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event, return 0; } -static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag) +static int resume_req_by_tag(BDRVBlkdebugState *s, const char *tag, bool all) { - BDRVBlkdebugState *s = bs->opaque; - BlkdebugSuspendedReq *r, *next; + BlkdebugSuspendedReq *r; - QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) { +retry: + /* + * No need for _SAFE, since a different coroutine can remove another node + * (not the current one) in this list, and when the current one is removed + * the iteration starts back from beginning anyways. + */ + QLIST_FOREACH(r, &s->suspended_reqs, next) { if (!strcmp(r->tag, tag)) { + QLIST_REMOVE(r, next); qemu_coroutine_enter(r->co); + if (all) { + goto retry; + } return 0; } } return -ENOENT; } +static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag) +{ + BDRVBlkdebugState *s = bs->opaque; + + return resume_req_by_tag(s, tag, false); +} + static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) { BDRVBlkdebugState *s = bs->opaque; - BlkdebugSuspendedReq *r, *r_next; BlkdebugRule *rule, *next; int i, ret = -ENOENT; @@ -900,11 +914,8 @@ static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs, } } } - QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) { - if (!strcmp(r->tag, tag)) { - qemu_coroutine_enter(r->co); - ret = 0; - } + if (resume_req_by_tag(s, tag, true) == 0) { + ret = 0; } return ret; }