From mboxrd@z Thu Jan 1 00:00:00 1970 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 smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 08E25C433EF for ; Thu, 12 May 2022 21:47:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id C2B4D415E0; Thu, 12 May 2022 21:47:34 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MQYdVBSTcsm2; Thu, 12 May 2022 21:47:33 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 8D13B416D6; Thu, 12 May 2022 21:47:32 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5D219C0086; Thu, 12 May 2022 21:47:32 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [IPv6:2605:bc80:3010::136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 42EC1C0081 for ; Thu, 12 May 2022 21:47:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 30DAE60634 for ; Thu, 12 May 2022 21:47:30 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp3.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=oracle.com header.b="f7Rbj/kY"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.b="ob6L/bxf" Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id k5LaHX-Oovhl for ; Thu, 12 May 2022 21:47:29 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by smtp3.osuosl.org (Postfix) with ESMTPS id 2A9BE60681 for ; Thu, 12 May 2022 21:47:29 +0000 (UTC) Received: from pps.filterd (m0246630.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24CJxkOS010429; Thu, 12 May 2022 21:47:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : content-transfer-encoding : content-type : mime-version; s=corp-2021-07-09; bh=wCzJ+fhQFHx8Vjbt3S2LgdprYaZhra/6gCOdfsGEKos=; b=f7Rbj/kYo84axy21hWojgBDDW2Z8QgiPUbKPj8vRX87WPPVDzyZ48JlISF3iggZHZgIs Q1Thmlzj0/mC1B1oN3fscmS30xrULrCrhtpepMuNwh6lFmhiCoMlz7d7n4RkPrhJf4Xy thgEDWxkUlpTTRkDFM0CP8BsU0Cpg1Ke64D3cTf95iRw26yfgHMhE+TrD1xOclyb7FBn cajpCGFPwRlQv7fKjEXwpJBF/UUTwwgh/a3pkdxlBvFWDWcU4BiJepNH0du6TDaJ6XdO eCmFt/CAGSk2bYO8ATtBemv6d4Z/jRQCgex+Drv2QwcoMeU2XOOEAL0Gc31E9W5e6Xd2 IQ== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3fwf6cdn01-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 May 2022 21:47:17 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.16.1.2/8.16.1.2) with SMTP id 24CLgIkP004728; Thu, 12 May 2022 21:47:16 GMT Received: from nam10-bn7-obe.outbound.protection.outlook.com (mail-bn7nam10lp2101.outbound.protection.outlook.com [104.47.70.101]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com with ESMTP id 3fwf7c98s9-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 May 2022 21:47:16 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=OrEYnAYj8qXtYo+/Gp5IWIcJWKWU5JXTC3IGaeZ0lKCdviGw3sACjyqTeb5aVOP1jjNuMO45uz3ntolT+TIC/g67G7ZKXJdPp2VXe1tvmU3aeNPHb35HFC4vrCGaHvJbNnm0Os0zScXDKTWCcTNRSGDlNlEbsXEhVMQ7ig4ZZhZY/6U2HPmdAO/LeaAzlQ/2o+DTAoxXu2sX+gjwV1HxtcqBE/SftHAuKKWZDNqwaTy4oNxcW3pAXXBI51P8fIA3VkRs4gcUQHrWXOf5PwpYI5u00z/83eZwoUwkUlBugMby+7tS3Fh3uNS/zmlP9yD1hYnAf23ulh6iuC5Xlgm59Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=wCzJ+fhQFHx8Vjbt3S2LgdprYaZhra/6gCOdfsGEKos=; b=Gt2uxpZkZGBc0PR1usi18pJlzQfIJcktoRlSBX1h8Osmnw5r0kwLxQE15pOLGYmdSxxVIVrxYm5btMP4wtz3c3scNy/5RqIm0WPNBiVvb9f4U9mCRoUlrUEzKcAabSNkw4B+ZY77TgjLGxR8WtMI97X9o+xcQHnFzglGJiSNeWvaS4d3OwdyZu0tTuPrYptDQ8w7aEyY47etCLRo1ZXkXVYa5DGsKRpCp08jPflcemdV+6B9smU7ZDoF5gBKiau2f+1qnz9Za5Pa4myB3LfpJd6PPj4mY8PizEib2Q/IfxsvlA98FrU8CESf62cD1PsWBGhhqt86y2GDrYTTyGcMNg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=wCzJ+fhQFHx8Vjbt3S2LgdprYaZhra/6gCOdfsGEKos=; b=ob6L/bxfVzTUT/BZUUdbMmidkPAwhwoecIgvkY7yZAGpBijFQjU1YZvR9SpTIeXT5+43ozkydZjF7VCk2P/xl5To/Rv5j6BIAEo5DLtACcBHPnEja1tDYbeXhFRVe/NAK5xsOMjV1I+P6LyiPrv24/HmeZS5mbtQqm6C9280so8= Received: from DM5PR10MB1466.namprd10.prod.outlook.com (2603:10b6:3:b::7) by MN2PR10MB3311.namprd10.prod.outlook.com (2603:10b6:208:121::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5250.13; Thu, 12 May 2022 21:47:15 +0000 Received: from DM5PR10MB1466.namprd10.prod.outlook.com ([fe80::f81d:b8ef:c5a4:9c9b]) by DM5PR10MB1466.namprd10.prod.outlook.com ([fe80::f81d:b8ef:c5a4:9c9b%3]) with mapi id 15.20.5227.023; Thu, 12 May 2022 21:47:15 +0000 From: Mike Christie To: hch@infradead.org, stefanha@redhat.com, jasowang@redhat.com, mst@redhat.com, sgarzare@redhat.com, virtualization@lists.linux-foundation.org, brauner@kernel.org, ebiederm@xmission.com, linux-kernel@vger.kernel.org Subject: [PATCH V9 6/8] vhost_task: Allow vhost layer to use copy_process Date: Thu, 12 May 2022 16:47:02 -0500 Message-Id: <20220512214704.104472-7-michael.christie@oracle.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220512214704.104472-1-michael.christie@oracle.com> References: <20220512214704.104472-1-michael.christie@oracle.com> X-ClientProxiedBy: DM5PR07CA0089.namprd07.prod.outlook.com (2603:10b6:4:ae::18) To DM5PR10MB1466.namprd10.prod.outlook.com (2603:10b6:3:b::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 0d9f6409-7565-43f2-659e-08da3460fa5e X-MS-TrafficTypeDiagnostic: MN2PR10MB3311:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DM5PR10MB1466.namprd10.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230001)(366004)(5660300002)(2906002)(66556008)(66476007)(316002)(66946007)(508600001)(36756003)(6486002)(26005)(6512007)(4326008)(8676002)(6666004)(6506007)(186003)(38350700002)(38100700002)(83380400001)(8936002)(2616005)(107886003)(1076003)(52116002)(86362001); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Mey+TXyrgdvoLpPMwWRRiRXnsdULMqp7O+UTdxwqkYfk/9rt0Ca9EwSm/r7V?= =?us-ascii?Q?IG+CX6M468PClfJN4O2x4moKkaqXwNggZP5sz4fLqvAXoLI90TCVuc2c3LYR?= =?us-ascii?Q?ZWeGbYz9Dxs9vGc5Wc004qySy3aEVdX/VTnUOk4N3UXF7PT2Pgb1k9uj9oxL?= =?us-ascii?Q?PAB807nyPP/M7KqYjnuneM7wHRS28/JMislDWH/q63nvLCTRGBZWf/gaVrY4?= =?us-ascii?Q?TMSU6vD4qzfuskzUotl/b+Rb+m2pJUvMuCMByhJ5AU7X2OuMPUUr7xzjvMM+?= =?us-ascii?Q?mR0j6h0gdF01Dg0dsx+Xxm57DmELL4V2SuKBlZV77tjjdMHBhPSAen5WZLt3?= =?us-ascii?Q?UZIj52nDixTpe4MAv2PNNmw39LWNe2p1Gra+6I342BQfe8BHHs89jYybUkJF?= =?us-ascii?Q?ZkR6fzpslrUnH2Xz/qHobeJNnYFZjabNowUN5IDDETJ5DhrFmqhqxCPORBjg?= =?us-ascii?Q?M6RZKMIIgSytMgkr0Q0J8aH4j2H7lxaTrTF9DWbFJr9jeTl4MO6cYh4Fgjxh?= =?us-ascii?Q?zNb6sx6ayMUXag7MrNiPLGmpIeTIVB6NA7eomRneyhQDGEI2NMu3DqSduiql?= =?us-ascii?Q?fyS9YMiALitnznCdbXisfq3K7Cq9k4gbZKt0mc0WAN8xcUOnOD5lf712BhCa?= =?us-ascii?Q?TxWJFsLjMWGOqvj8l5Q/x6sQZG0v6isUIjyibmV7w0QHBInIwgkqrMvvpML2?= =?us-ascii?Q?fg8Z/bH6KKy8Gv4HMvdQkbQj3TUfQ9MKjowQQIEtPwmusB88n4j17ibNgg+b?= =?us-ascii?Q?fpbV3EHTrKGFaSH3FYagWAyuVTh6PEAypDjiPjxRQxR0spjREFPO4hVirnbt?= =?us-ascii?Q?7hpnKDmyekm6TlHeSrMVWWkyXG0rIPO+QIE7bHzr0Sua94rUWwnc9qy+GXWN?= =?us-ascii?Q?lf4xmxnNP4uVEWpdzvWWXrdcMqoZPCoDupjXjqT3YkDlQPE/L+VYpgcjBsO/?= =?us-ascii?Q?9zEnr5vXInAl/0tya6FS/G4dLAq6C+M0bc0KU/Kw9zNkASHcDSWWSTXfpUJx?= =?us-ascii?Q?3y3m1+Ji1SKoq7VJCZbndR+rGCsitf9FKmHRfrCcYOxfspHei3Bli6++Dz5f?= =?us-ascii?Q?DpFJGEt6nqhpfdyxHp79e1iblU3LnU0E+dJk0y/oWY84oRgkfHgGbButMnPZ?= =?us-ascii?Q?EXcNIVVX17GZagl8X/TTQ8V+Dsf7nXZYCHW6xvtGSERo9T+wjX7AkXxYm+N5?= =?us-ascii?Q?+pt3iLE8+co6CSgo1rPLaNGkYbKXkRf6xEth+sGjGd69JitdNndl0zgvSotP?= =?us-ascii?Q?L0G0WEXPqslLUhuuducOZIbXJKjRLcIMPMl46n4F/wYYZ13E3GT2tb6qr6Ar?= =?us-ascii?Q?+EW5hzX0+ZDoyxl1dYgoqtpXDGI7LN98LsF85ZMSTbpatr+nqji2OVv8qbdS?= =?us-ascii?Q?nzi0s3Gv1pqBLYHXcfBwmx26vzKDuCitzm7MnVxc5/kWoD3rTPuwkMiOSgRT?= =?us-ascii?Q?la0/xLt9W2mqV7M9B29qVYrJf/9j+OQiryAnr48Y8l4Tx7BkedYekKpoI4ko?= =?us-ascii?Q?fjMNUVLLyEQh53IscLjWTro+T3oCBrGub0h9tglDw3krsHKdMIYS9zChIK9Z?= =?us-ascii?Q?MHvkwz0/eSENX7j7EKBEPuvW3IdJaVRKTviuy8p3E4mkrvI20jhUGNgDwD4Y?= =?us-ascii?Q?sF4f+q5eRm8vqHe9V+sXAtjhw3GKjhJUlecHehwfuapgeHdlATvBhy1tbHax?= =?us-ascii?Q?XC0FCjTVzbCJrK0wXF5j0oSGwfaDgSePsPeVoegtpICUUHZt9thCWfuY0vjC?= =?us-ascii?Q?qmcCsM/V+Cdi7KL5Mz9BhNHkYziiUSY=3D?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0d9f6409-7565-43f2-659e-08da3460fa5e X-MS-Exchange-CrossTenant-AuthSource: DM5PR10MB1466.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 May 2022 21:47:14.9591 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: ISeGuq5oXdC0VYUFq9DHiJlOXM9FMAFUxBiQuTcp07DbvuAjMhYJyU9PoL+MToVDoTVHgX6t8p+POX+otwXrWQm3TXhXFL9pNjIagzjjiEU= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR10MB3311 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.486, 18.0.858 definitions=2022-05-12_13:2022-05-12, 2022-05-12 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxlogscore=999 spamscore=0 bulkscore=0 adultscore=0 suspectscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205120091 X-Proofpoint-ORIG-GUID: aJP910P5OPdO0ewXR_FyDNI3XIVs4zwM X-Proofpoint-GUID: aJP910P5OPdO0ewXR_FyDNI3XIVs4zwM X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" Qemu will create vhost devices in the kernel which perform network, SCSI, etc IO and management operations from worker threads created by the kthread API. Because the kthread API does a copy_process on the kthreadd thread, the vhost layer has to use kthread_use_mm to access the Qemu thread's memory and cgroup_attach_task_all to add itself to the Qemu thread's cgroups, and it bypasses the RLIMIT_NPROC limit which can result in VMs creating more threads than the admin expected. This patch adds a new struct vhost_task which can be used instead of kthreads. They allow the vhost layer to use copy_process and inherit the userspace process's mm and cgroups, the task is accounted for under the userspace's nproc count and can be seen in its process tree, and other features like namespaces work and are inherited by default. Signed-off-by: Mike Christie --- MAINTAINERS | 2 + drivers/vhost/Kconfig | 5 ++ include/linux/sched/vhost_task.h | 23 ++++++ kernel/Makefile | 1 + kernel/vhost_task.c | 122 +++++++++++++++++++++++++++++++ 5 files changed, 153 insertions(+) create mode 100644 include/linux/sched/vhost_task.h create mode 100644 kernel/vhost_task.c diff --git a/MAINTAINERS b/MAINTAINERS index e8c52d0192a6..94c77f4a1ecb 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20919,7 +20919,9 @@ L: virtualization@lists.linux-foundation.org L: netdev@vger.kernel.org S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git +F: kernel/vhost_task.c F: drivers/vhost/ +F: include/linux/sched/vhost_task.h F: include/linux/vhost_iotlb.h F: include/uapi/linux/vhost.h diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig index 587fbae06182..b455d9ab6f3d 100644 --- a/drivers/vhost/Kconfig +++ b/drivers/vhost/Kconfig @@ -13,9 +13,14 @@ config VHOST_RING This option is selected by any driver which needs to access the host side of a virtio ring. +config VHOST_TASK + bool + default n + config VHOST tristate select VHOST_IOTLB + select VHOST_TASK help This option is selected by any driver which needs to access the core of vhost. diff --git a/include/linux/sched/vhost_task.h b/include/linux/sched/vhost_task.h new file mode 100644 index 000000000000..50d02a25d37b --- /dev/null +++ b/include/linux/sched/vhost_task.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_VHOST_TASK_H +#define _LINUX_VHOST_TASK_H + +#include + +struct task_struct; + +struct vhost_task { + int (*fn)(void *data); + void *data; + struct completion exited; + unsigned long flags; + struct task_struct *task; +}; + +struct vhost_task *vhost_task_create(int (*fn)(void *), void *arg, int node); +__printf(2, 3) +void vhost_task_start(struct vhost_task *vtsk, const char namefmt[], ...); +void vhost_task_stop(struct vhost_task *vtsk); +bool vhost_task_should_stop(struct vhost_task *vtsk); + +#endif diff --git a/kernel/Makefile b/kernel/Makefile index 847a82bfe0e3..7fbf3eb6a86b 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -15,6 +15,7 @@ obj-y = fork.o exec_domain.o panic.o \ obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o obj-$(CONFIG_MODULES) += kmod.o obj-$(CONFIG_MULTIUSER) += groups.o +obj-$(CONFIG_VHOST_TASK) += vhost_task.o ifdef CONFIG_FUNCTION_TRACER # Do not trace internal ftrace files diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c new file mode 100644 index 000000000000..517dd166bb2b --- /dev/null +++ b/kernel/vhost_task.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021 Oracle Corporation + */ +#include +#include +#include +#include +#include + +enum vhost_task_flags { + VHOST_TASK_FLAGS_STOP, +}; + +static int vhost_task_fn(void *data) +{ + struct vhost_task *vtsk = data; + int ret; + + ret = vtsk->fn(vtsk->data); + complete(&vtsk->exited); + do_exit(ret); +} + +/** + * vhost_task_stop - stop a vhost_task + * @vtsk: vhost_task to stop + * + * Callers must call vhost_task_should_stop and return from their worker + * function when it returns true; + */ +void vhost_task_stop(struct vhost_task *vtsk) +{ + pid_t pid = vtsk->task->pid; + + set_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags); + wake_up_process(vtsk->task); + /* + * Make sure vhost_task_fn is no longer accessing the vhost_task before + * freeing it below. If userspace crashed or exited without closing, + * then the vhost_task->task could already be marked dead so + * kernel_wait will return early. + */ + wait_for_completion(&vtsk->exited); + /* + * If we are just closing/removing a device and the parent process is + * not exiting then reap the task. + */ + kernel_wait4(pid, NULL, __WCLONE, NULL); + kfree(vtsk); +} +EXPORT_SYMBOL_GPL(vhost_task_stop); + +/** + * vhost_task_should_stop - should the vhost task return from the work function + */ +bool vhost_task_should_stop(struct vhost_task *vtsk) +{ + return test_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags); +} +EXPORT_SYMBOL_GPL(vhost_task_should_stop); + +/** + * vhost_task_create - create a copy of a process to be used by the kernel + * @fn: thread stack + * @arg: data to be passed to fn + * @node: numa node to allocate task from + * + * This returns a specialized task for use by the vhost layer or NULL on + * failure. The returned task is inactive, and the caller must fire it up + * through vhost_task_start(). + */ +struct vhost_task *vhost_task_create(int (*fn)(void *), void *arg, int node) +{ + struct kernel_clone_args args = { + .flags = CLONE_FS | CLONE_UNTRACED | CLONE_VM, + .exit_signal = 0, + .worker_flags = USER_WORKER | USER_WORKER_NO_FILES | + USER_WORKER_SIG_IGN, + .fn = vhost_task_fn, + }; + struct vhost_task *vtsk; + struct task_struct *tsk; + + vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL); + if (!vtsk) + return ERR_PTR(-ENOMEM); + init_completion(&vtsk->exited); + vtsk->data = arg; + vtsk->fn = fn; + + args.fn_arg = vtsk; + + tsk = copy_process(NULL, 0, node, &args); + if (IS_ERR(tsk)) { + kfree(vtsk); + return NULL; + } + + vtsk->task = tsk; + return vtsk; +} +EXPORT_SYMBOL_GPL(vhost_task_create); + +/** + * vhost_task_start - start a vhost_task created with vhost_task_create + * @vtsk: vhost_task to wake up + * @namefmt: printf-style format string for the thread name + */ +void vhost_task_start(struct vhost_task *vtsk, const char namefmt[], ...) +{ + char name[TASK_COMM_LEN]; + va_list args; + + va_start(args, namefmt); + vsnprintf(name, sizeof(name), namefmt, args); + set_task_comm(vtsk->task, name); + va_end(args); + + wake_up_new_task(vtsk->task); +} +EXPORT_SYMBOL_GPL(vhost_task_start); -- 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization