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 4F6F1E95A91 for ; Mon, 9 Oct 2023 09:35:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345796AbjJIJfY (ORCPT ); Mon, 9 Oct 2023 05:35:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345753AbjJIJfY (ORCPT ); Mon, 9 Oct 2023 05:35:24 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BE8FA3 for ; Mon, 9 Oct 2023 02:34:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1696844078; 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=DfRxw27qVBIdPCd6o1lBvFpTVHLecT139zgNuCHJ+mo=; b=ZoCKS28GZ6ZkS3Q8BCtYmyn6Tck+VY6p23eR9E3LPq5026J8GUiKwoa8hZT+F3ds6kHZVQ Hyy7/y1R1RMQFX5tUgaLoii7MFybzCuOY6veGHcEvTFhyRMOeeBEwNOTqRQDO13jVRe/CC 0D4qcRRcYUeY5HfjH6/u8lxKWwkAouE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-486-5U-cS7sBNKi9Zeal4lr_CQ-1; Mon, 09 Oct 2023 05:34:33 -0400 X-MC-Unique: 5U-cS7sBNKi9Zeal4lr_CQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 319C1101A598; Mon, 9 Oct 2023 09:34:33 +0000 (UTC) Received: from localhost (unknown [10.72.120.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 643DA140E962; Mon, 9 Oct 2023 09:34:32 +0000 (UTC) From: Ming Lei To: Jens Axboe , io-uring@vger.kernel.org, linux-block@vger.kernel.org Cc: Ming Lei Subject: [PATCH for-6.7/io_uring 2/7] ublk: make sure io cmd handled in submitter task context Date: Mon, 9 Oct 2023 17:33:17 +0800 Message-ID: <20231009093324.957829-3-ming.lei@redhat.com> In-Reply-To: <20231009093324.957829-1-ming.lei@redhat.com> References: <20231009093324.957829-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org In well-done ublk server implementation, ublk io command won't be linked into any link chain. Meantime they are always handled in no-wait style, so basically io cmd is always handled in submitter task context. However, the server may set IOSQE_ASYNC, or io command is linked to one chain mistakenly, then we may still run into io-wq context and ctx->uring_lock isn't held. So in case of IO_URING_F_UNLOCKED, schedule this command by io_uring_cmd_complete_in_task to force running it in submitter task. Then ublk_ch_uring_cmd_local() is guaranteed to run with context uring_lock held, and we needn't to worry about sync among submission code path any more. Signed-off-by: Ming Lei --- drivers/block/ublk_drv.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 9b3c0b3dd36e..46d499d96ca3 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1810,7 +1810,8 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub, return NULL; } -static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) +static inline int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, + unsigned int issue_flags) { /* * Not necessary for async retry, but let's keep it simple and always @@ -1824,9 +1825,28 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) .addr = READ_ONCE(ub_src->addr) }; + WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED); + return __ublk_ch_uring_cmd(cmd, issue_flags, &ub_cmd); } +static void ublk_ch_uring_cmd_cb(struct io_uring_cmd *cmd, + unsigned int issue_flags) +{ + ublk_ch_uring_cmd_local(cmd, issue_flags); +} + +static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) +{ + /* well-implemented server won't run into unlocked */ + if (unlikely(issue_flags & IO_URING_F_UNLOCKED)) { + io_uring_cmd_complete_in_task(cmd, ublk_ch_uring_cmd_cb); + return -EIOCBQUEUED; + } + + return ublk_ch_uring_cmd_local(cmd, issue_flags); +} + static inline bool ublk_check_ubuf_dir(const struct request *req, int ubuf_dir) { -- 2.41.0