From patchwork Thu Jul 16 12:48:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Garzarella X-Patchwork-Id: 11667369 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 30B711392 for ; Thu, 16 Jul 2020 12:49:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17B6720787 for ; Thu, 16 Jul 2020 12:49:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eWOr+093" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728477AbgGPMtT (ORCPT ); Thu, 16 Jul 2020 08:49:19 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:38922 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726963AbgGPMtT (ORCPT ); Thu, 16 Jul 2020 08:49:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594903757; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3IGotHJLDWHOMS4jfIFhav0o5esf4avDkRICTFAhyCo=; b=eWOr+093cEyvrAhd9hRHr7n39z4L9Zecs2UCNotmO35StWMk60L8CPNvUtPHXB3oGV2TJd 6g0dDuOM8BtNZl3qVwwAjJYZNbXvQq2bxnSH4Qcwe4sIesOt+Z2Dnxjk8CGLQgFSCTsEOb 2irtYRW1e71g89fTu9c0jLvvcP7q2Vc= 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-206-wSe4nHhrMv606IQIZUQ-PQ-1; Thu, 16 Jul 2020 08:49:15 -0400 X-MC-Unique: wSe4nHhrMv606IQIZUQ-PQ-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 8A2C71B18BC1; Thu, 16 Jul 2020 12:49:13 +0000 (UTC) Received: from steredhat.redhat.com (ovpn-114-107.ams2.redhat.com [10.36.114.107]) by smtp.corp.redhat.com (Postfix) with ESMTP id 727D117D04; Thu, 16 Jul 2020 12:49:00 +0000 (UTC) From: Stefano Garzarella To: Jens Axboe Cc: Alexander Viro , Kernel Hardening , Kees Cook , Aleksa Sarai , Stefan Hajnoczi , Christian Brauner , Sargun Dhillon , Jann Horn , io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jeff Moyer , linux-kernel@vger.kernel.org Subject: [PATCH RFC v2 3/3] io_uring: allow disabling rings during the creation Date: Thu, 16 Jul 2020 14:48:33 +0200 Message-Id: <20200716124833.93667-4-sgarzare@redhat.com> In-Reply-To: <20200716124833.93667-1-sgarzare@redhat.com> References: <20200716124833.93667-1-sgarzare@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This patch adds a new IORING_SETUP_R_DISABLED flag to start the rings disabled, allowing the user to register restrictions, buffers, files, before to start processing SQEs. When IORING_SETUP_R_DISABLED is set, SQE are not processed and SQPOLL kthread is not started. The restrictions registration are allowed only when the rings are disable to prevent concurrency issue while processing SQEs. The rings can be enabled using IORING_REGISTER_ENABLE_RINGS opcode with io_uring_register(2). Suggested-by: Jens Axboe Signed-off-by: Stefano Garzarella --- RFC v2: - removed return value of io_sq_offload_start() --- fs/io_uring.c | 50 +++++++++++++++++++++++++++++------ include/uapi/linux/io_uring.h | 2 ++ 2 files changed, 44 insertions(+), 8 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 23a2b03d9528..2f2ecfa10c94 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6969,8 +6969,8 @@ static int io_init_wq_offload(struct io_ring_ctx *ctx, return ret; } -static int io_sq_offload_start(struct io_ring_ctx *ctx, - struct io_uring_params *p) +static int io_sq_offload_create(struct io_ring_ctx *ctx, + struct io_uring_params *p) { int ret; @@ -7007,7 +7007,6 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, ctx->sqo_thread = NULL; goto err; } - wake_up_process(ctx->sqo_thread); } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ ret = -EINVAL; @@ -7026,6 +7025,12 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, return ret; } +static void io_sq_offload_start(struct io_ring_ctx *ctx) +{ + if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sqo_thread) + wake_up_process(ctx->sqo_thread); +} + static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) { atomic_long_sub(nr_pages, &user->locked_vm); @@ -7654,9 +7659,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, int submitted = 0; struct fd f; - if (current->task_works) - task_work_run(); - if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP)) return -EINVAL; @@ -7673,6 +7675,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, if (!percpu_ref_tryget(&ctx->refs)) goto out_fput; + if (ctx->flags & IORING_SETUP_R_DISABLED) + return -EBADF; + + if (current->task_works) + task_work_run(); + /* * For SQ polling, the thread will do all submissions and completions. * Just return the requested submit count, and wake the thread if @@ -7978,10 +7986,13 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p, if (ret) goto err; - ret = io_sq_offload_start(ctx, p); + ret = io_sq_offload_create(ctx, p); if (ret) goto err; + if (!(p->flags & IORING_SETUP_R_DISABLED)) + io_sq_offload_start(ctx); + memset(&p->sq_off, 0, sizeof(p->sq_off)); p->sq_off.head = offsetof(struct io_rings, sq.head); p->sq_off.tail = offsetof(struct io_rings, sq.tail); @@ -8042,7 +8053,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | - IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ)) + IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ | + IORING_SETUP_R_DISABLED)) return -EINVAL; return io_uring_create(entries, &p, params); @@ -8125,6 +8137,10 @@ static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg, size_t size; int i, ret; + /* Restrictions allowed only if rings started disabled */ + if (!(ctx->flags & IORING_SETUP_R_DISABLED)) + return -EINVAL; + /* We allow only a single restrictions registration */ if (ctx->restricted) return -EBUSY; @@ -8183,6 +8199,18 @@ static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg, return ret; } +static int io_register_enable_rings(struct io_ring_ctx *ctx) +{ + if (!(ctx->flags & IORING_SETUP_R_DISABLED)) + return -EINVAL; + + ctx->flags &= ~IORING_SETUP_R_DISABLED; + + io_sq_offload_start(ctx); + + return 0; +} + static bool io_register_op_must_quiesce(int op) { switch (op) { @@ -8304,6 +8332,12 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; ret = io_unregister_personality(ctx, nr_args); break; + case IORING_REGISTER_ENABLE_RINGS: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_register_enable_rings(ctx); + break; case IORING_REGISTER_RESTRICTIONS: ret = io_register_restrictions(ctx, arg, nr_args); break; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 0774d5382c65..ce52333bdc2b 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -94,6 +94,7 @@ enum { #define IORING_SETUP_CQSIZE (1U << 3) /* app defines CQ size */ #define IORING_SETUP_CLAMP (1U << 4) /* clamp SQ/CQ ring sizes */ #define IORING_SETUP_ATTACH_WQ (1U << 5) /* attach to existing wq */ +#define IORING_SETUP_R_DISABLED (1U << 6) /* start with ring disabled */ enum { IORING_OP_NOP, @@ -266,6 +267,7 @@ enum { IORING_REGISTER_PERSONALITY, IORING_UNREGISTER_PERSONALITY, IORING_REGISTER_RESTRICTIONS, + IORING_REGISTER_ENABLE_RINGS, /* this goes last */ IORING_REGISTER_LAST