From patchwork Thu Jan 30 10:08:22 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Maciej S. Szmigiero" X-Patchwork-Id: 13954426 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 96CA4C02190 for ; Thu, 30 Jan 2025 10:10:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tdRUI-000279-O4; Thu, 30 Jan 2025 05:09:30 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdRUG-00026q-Vi for qemu-devel@nongnu.org; Thu, 30 Jan 2025 05:09:28 -0500 Received: from vps-ovh.mhejs.net ([145.239.82.108]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdRUE-00071e-OZ for qemu-devel@nongnu.org; Thu, 30 Jan 2025 05:09:28 -0500 Received: from MUA by vps-ovh.mhejs.net with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.98) (envelope-from ) id 1tdRU4-00000006Tw9-0N6B; Thu, 30 Jan 2025 11:09:16 +0100 From: "Maciej S. Szmigiero" To: Peter Xu , Fabiano Rosas Cc: Alex Williamson , =?utf-8?q?C=C3=A9dric_Le_G?= =?utf-8?q?oater?= , Eric Blake , Markus Armbruster , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= , Avihai Horon , Joao Martins , qemu-devel@nongnu.org Subject: [PATCH v4 01/33] migration: Clarify that {load, save}_cleanup handlers can run without setup Date: Thu, 30 Jan 2025 11:08:22 +0100 Message-ID: <6e82ce38c115d5eec03d7955d94f96050491a1d5.1738171076.git.maciej.szmigiero@oracle.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=145.239.82.108; envelope-from=mhej@vps-ovh.mhejs.net; helo=vps-ovh.mhejs.net X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.037, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: "Maciej S. Szmigiero" It's possible for {load,save}_cleanup SaveVMHandlers to get called without the corresponding {load,save}_setup handler being called first. One such example is if {load,save}_setup handler of a proceeding device returns error. In this case the migration core cleanup code will call all corresponding cleanup handlers, even for these devices which haven't had its setup handler called. Since this behavior can generate some surprises let's clearly document it in these SaveVMHandlers description. Reviewed-by: Fabiano Rosas Reviewed-by: Cédric Le Goater Signed-off-by: Maciej S. Szmigiero --- include/migration/register.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/include/migration/register.h b/include/migration/register.h index f60e797894e5..0b0292738320 100644 --- a/include/migration/register.h +++ b/include/migration/register.h @@ -69,7 +69,9 @@ typedef struct SaveVMHandlers { /** * @save_cleanup * - * Uninitializes the data structures on the source + * Uninitializes the data structures on the source. + * Note that this handler can be called even if save_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() */ @@ -244,6 +246,8 @@ typedef struct SaveVMHandlers { * @load_cleanup * * Uninitializes the data structures on the destination. + * Note that this handler can be called even if load_setup + * wasn't called earlier. * * @opaque: data pointer passed to register_savevm_live() *