From patchwork Tue Jul 16 16:26:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Zhao Liu X-Patchwork-Id: 13734672 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 EDA80C3DA49 for ; Tue, 16 Jul 2024 16:11:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sTklc-0002PF-D5; Tue, 16 Jul 2024 12:11:05 -0400 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 1sTklS-0001sf-ON for qemu-devel@nongnu.org; Tue, 16 Jul 2024 12:10:56 -0400 Received: from mgamail.intel.com ([198.175.65.14]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sTklQ-0002wx-Mx for qemu-devel@nongnu.org; Tue, 16 Jul 2024 12:10:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1721146252; x=1752682252; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=Xz4aX8dBW2vbxRdbOQqpj1yin6IORC1tzbkn3pSN2EE=; b=OKhMw1ZtSH2jlgIaJPmdnhfE7KNovWxGYmRpiYVu2jSP/wpbMDlBqf1b +r42cR1+9lqmO9dbkcPZPE5RTAKWsdPbWzSpvz79dcYz7cElRQ8vkslgQ F4kxNRqot17WzDSEFS+D34+hswTMQQAEvJlPVXT87UfS/BDhPhQDgl57z 4g/mBdzxQKEo71bAgi6i0RuzpvRs/ljWCdBO45Jzd26y1JEQfik+fCK44 E7WkKOqJ0DwH5VPRy6oYF49qLpocfOP5Z+qBSEO6vj9D85AYnNDCwnZ8E 0ztGysuSQeQesXZrp7iJUUrrYoEZ/L542FVN+EnSCXUeqOwmWmcvoSnnx Q==; X-CSE-ConnectionGUID: WAVyj2XpSIGrvFyK9cK5Bw== X-CSE-MsgGUID: vwAkZaHhR9yAssQ6c6tIPQ== X-IronPort-AV: E=McAfee;i="6700,10204,11135"; a="22410115" X-IronPort-AV: E=Sophos;i="6.09,212,1716274800"; d="scan'208";a="22410115" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2024 09:10:51 -0700 X-CSE-ConnectionGUID: xDl6QyBIRiCHGF6s/4TjFw== X-CSE-MsgGUID: K7hEYVqHR46B6UVcjecPTw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,212,1716274800"; d="scan'208";a="49940499" Received: from liuzhao-optiplex-7080.sh.intel.com ([10.239.160.36]) by orviesa010.jf.intel.com with ESMTP; 16 Jul 2024 09:10:50 -0700 From: Zhao Liu To: =?utf-8?q?Eugenio_P=C3=A9rez?= , qemu-devel@nongnu.org Cc: Zhao Liu , "Michael S. Tsirkin" , Jason Wang Subject: [PATCH v2] hw/virtio/vdpa-dev: Check returned value instead of dereferencing @errp Date: Wed, 17 Jul 2024 00:26:15 +0800 Message-Id: <20240716162615.271010-1-zhao1.liu@intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Received-SPF: pass client-ip=198.175.65.14; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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: 2.1.29 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 As the comment in qapi/error, dereferencing @errp requires ERRP_GUARD(): * = Why, when and how to use ERRP_GUARD() = * * Without ERRP_GUARD(), use of the @errp parameter is restricted: * - It must not be dereferenced, because it may be null. ... * ERRP_GUARD() lifts these restrictions. * * To use ERRP_GUARD(), add it right at the beginning of the function. * @errp can then be used without worrying about the argument being * NULL or &error_fatal. * * Using it when it's not needed is safe, but please avoid cluttering * the source with useless code. Though vhost_vdpa_device_realize() is called at DeviceClass.realize() context and won't get NULL @errp, it's still better to follow the requirement to add the ERRP_GUARD(). But qemu_open() and vhost_vdpa_device_get_u32()'s return values can distinguish between successful and unsuccessful calls, so check the return values directly without dereferencing @errp, which eliminates the need of ERRP_GUARD(). Cc: "Michael S. Tsirkin" Cc: Jason Wang Acked-by: Eugenio Pérez Signed-off-by: Zhao Liu --- v2: * Added a/b from Eugenio. * Deleted unnecessary ERRP_GUARD(). (Eugenio) --- hw/virtio/vdpa-dev.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c index 64b96b226c39..8a1e16fce3de 100644 --- a/hw/virtio/vdpa-dev.c +++ b/hw/virtio/vdpa-dev.c @@ -63,19 +63,19 @@ static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp) } v->vhostfd = qemu_open(v->vhostdev, O_RDWR, errp); - if (*errp) { + if (v->vhostfd < 0) { return; } v->vdev_id = vhost_vdpa_device_get_u32(v->vhostfd, VHOST_VDPA_GET_DEVICE_ID, errp); - if (*errp) { + if (v->vdev_id < 0) { goto out; } max_queue_size = vhost_vdpa_device_get_u32(v->vhostfd, VHOST_VDPA_GET_VRING_NUM, errp); - if (*errp) { + if (max_queue_size < 0) { goto out; } @@ -89,7 +89,7 @@ static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp) v->num_queues = vhost_vdpa_device_get_u32(v->vhostfd, VHOST_VDPA_GET_VQS_COUNT, errp); - if (*errp) { + if (v->num_queues < 0) { goto out; } @@ -127,7 +127,7 @@ static void vhost_vdpa_device_realize(DeviceState *dev, Error **errp) v->config_size = vhost_vdpa_device_get_u32(v->vhostfd, VHOST_VDPA_GET_CONFIG_SIZE, errp); - if (*errp) { + if (v->config_size < 0) { goto vhost_cleanup; }