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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 314AEC64EC4 for ; Wed, 22 Feb 2023 13:26:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231712AbjBVN0N (ORCPT ); Wed, 22 Feb 2023 08:26:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229673AbjBVN0M (ORCPT ); Wed, 22 Feb 2023 08:26:12 -0500 Received: from out30-119.freemail.mail.aliyun.com (out30-119.freemail.mail.aliyun.com [115.124.30.119]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B52983B645; Wed, 22 Feb 2023 05:25:43 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VcGxflu_1677072336; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0VcGxflu_1677072336) by smtp.aliyun-inc.com; Wed, 22 Feb 2023 21:25:37 +0800 From: Xiaoguang Wang To: linux-block@vger.kernel.org, io-uring@vger.kernel.org, bpf@vger.kernel.org Cc: ming.lei@redhat.com, axboe@kernel.dk, asml.silence@gmail.com, ZiyangZhang@linux.alibaba.com Subject: [RFC v2 3/4] io_uring: introduce IORING_URING_CMD_UNLOCK flag Date: Wed, 22 Feb 2023 21:25:33 +0800 Message-Id: <20230222132534.114574-4-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230222132534.114574-1-xiaoguang.wang@linux.alibaba.com> References: <20230222132534.114574-1-xiaoguang.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org task_work_cb and its child functions may call io_uring_submit_sqe() in io_uring_cmd's callback, so to avoid ctx->uring_lock deadlock, introduce IORING_URING_CMD_UNLOCK to unlock uring_lock temporarily in io_uring_cmd_work(). Signed-off-by: Xiaoguang Wang --- include/uapi/linux/io_uring.h | 5 +++++ io_uring/uring_cmd.c | 6 +++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 2780bce62faf..45ea8c35d251 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -232,8 +232,13 @@ enum io_uring_op { * sqe->uring_cmd_flags * IORING_URING_CMD_FIXED use registered buffer; pass this flag * along with setting sqe->buf_index. + * + * IORING_URING_CMD_UNLOCK Notify io_uring_cmd's task_work_cb to + * unlock uring_lock, some ->uring_cmd() + * implementations need it. */ #define IORING_URING_CMD_FIXED (1U << 0) +#define IORING_URING_CMD_UNLOCK (1U << 1) /* diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index 446a189b78b0..11488a702832 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -16,7 +16,11 @@ static void io_uring_cmd_work(struct io_kiocb *req, bool *locked) { struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); + if ((req->flags & IORING_URING_CMD_UNLOCK) && *locked) + mutex_unlock(&(req->ctx->uring_lock)); ioucmd->task_work_cb(ioucmd); + if ((req->flags & IORING_URING_CMD_UNLOCK) && *locked) + mutex_lock(&(req->ctx->uring_lock)); } void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd, @@ -82,7 +86,7 @@ int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) return -EINVAL; ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags); - if (ioucmd->flags & ~IORING_URING_CMD_FIXED) + if (ioucmd->flags & ~(IORING_URING_CMD_FIXED | IORING_URING_CMD_UNLOCK)) return -EINVAL; if (ioucmd->flags & IORING_URING_CMD_FIXED) { -- 2.31.1