From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f48.google.com (mail-ej1-f48.google.com [209.85.218.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CCBEA33CF1; Mon, 18 Mar 2024 12:47:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710766080; cv=none; b=PYcKq7G79tg0VfBBPFI1x7nT7ZkN7I9KOQNLvgijOshmiyG80m3OPvbpbNoBarRe4ygAV1a97fIodaiEjFrUgSHJDOGZ/iCwQovUXwM+IzBT3GOgWTyK2NUjxcrOOJZBpD64HARRiFMxS5/zlNaZJUNWU6BxTu1BMpfTOSsY8zo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710766080; c=relaxed/simple; bh=NJO/OzF1aEQatl4gEGcESSz+6SPZB88Lyx//qMfh00M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oIAmBF5KIvP4TaoRRPd5HFsWg42cSyvioPDqz/6CwX0qkEplS0t3NHI3Bc6A3tWud2obl36QeQZlfi5LZPGomxfYn4hkj9xCMrcv+yhTvT/P1v1Na0Eo1J404rk2VzeZRfXihzlIYVmaXVrszaQ/eRS+q7sELZNg98/2ooJJFws= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=PEJ6eKb5; arc=none smtp.client-ip=209.85.218.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PEJ6eKb5" Received: by mail-ej1-f48.google.com with SMTP id a640c23a62f3a-a466fc8fcccso514933466b.1; Mon, 18 Mar 2024 05:47:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1710766077; x=1711370877; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=eqXURLQe9rpwYXz0H2JbltKjmZxipM6zc+gmhvKvKfQ=; b=PEJ6eKb5ikvg84xjWgmiBZ+qPzgULkeRCTjt1qhwMyjd9HxwGJcQBndAwf/IAhIyNP HjswQmJrKwooB1h6NX1Orffak0e1xzpgCkGMdNj4IBpA2IkqAiTxtjo8lNZD7DY4Ocdf YkU8QCbIZeD/Ye8ULmc329H/c2X2YVFkR9DWvsbTuo8+H3G1oKlxdurlDMHUvfbLOXW1 G0JIJJdLG34XD4JtqWdxNjg9NoGY+Eu9QmeqZray5xBAuRjl3YcXUYRltffLYkPzc2R1 SIAkoRpfXwSMl9PPeop+i1Y0r6WDQcieB/Ddxnf0KCJX6Byf3OlKXLUPQOFhv8AfJ5Ch Mmow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710766077; x=1711370877; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=eqXURLQe9rpwYXz0H2JbltKjmZxipM6zc+gmhvKvKfQ=; b=RtWZ28F2zkIUs7xEOgPpMIHN8HAa3Sn6iQJ+8mLH9KT3H8niNDj5VQDEl6tUGCexQJ UPYAM0FBuFZdQfkpE7z1IuN13k+LK4BWBX2w1vuJTKCgVXtTm9uzcKVF4m6hoc4eeKUN xJLiEnVXR271l4a0Do2Au0GHio0nK7DRF5GUT/SGbT2iFI8zUQfzA51Xf1EEDO4ADEj7 O4sXMLruhwVmZmBpXadwHMOEbLXiepzP8xQwpZHTdlJDmL7/YsnBZB2YciDH7gmtVhBc GNMYfNP7ackeZVINKs+W2DPN6RaC4dHNxb2GL+H84k/bYjn8LcJqGcouZvJ46ryUHUIE 6m8g== X-Forwarded-Encrypted: i=1; AJvYcCUu3xfplL2GkfFG/ICEf6IoO0K53YLI48hWpuqP1Esv+WBeakASdF/DvqIp0V5AGveiYihNzXOlLACwtdJGaDDZAvFba2yg3IolAbI= X-Gm-Message-State: AOJu0Yza2hX2mdQNEYRUPJwhlEWzRGtsrZu7CW/hE814bao6xDCEmn2J EWaTeWap+SC5bMA93aA7jVQ5IktfN/rDwZEBL2HM9HkMr8zS39RmtkaSX5Sc X-Google-Smtp-Source: AGHT+IGy9tjxfnOCO86MR0H3gZf3/TqZa19jGUpGSxZLiitEfmnYZSRJ50Nlg10eiNLk6YY3AC4ICA== X-Received: by 2002:a17:906:a415:b0:a46:1f6d:3047 with SMTP id l21-20020a170906a41500b00a461f6d3047mr7801570ejz.4.1710766077077; Mon, 18 Mar 2024 05:47:57 -0700 (PDT) Received: from ?IPV6:2620:10d:c096:310::2181? ([2620:10d:c092:600::1:e42b]) by smtp.gmail.com with ESMTPSA id cu2-20020a170906e00200b00a4660b63502sm4887794ejb.12.2024.03.18.05.47.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Mar 2024 05:47:56 -0700 (PDT) Message-ID: <1f5c02ad-f25a-46ea-96e6-649997aea3c2@gmail.com> Date: Mon, 18 Mar 2024 12:46:25 +0000 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 03/14] io_uring/cmd: make io_uring_cmd_done irq safe Content-Language: en-US To: Ming Lei Cc: io-uring@vger.kernel.org, linux-block@vger.kernel.org, Jens Axboe , Kanchan Joshi References: <4c6a5b55-2833-4ef7-a514-577fe61160dd@gmail.com> From: Pavel Begunkov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 3/18/24 11:59, Ming Lei wrote: > On Mon, Mar 18, 2024 at 11:50:32AM +0000, Pavel Begunkov wrote: >> On 3/18/24 08:10, Ming Lei wrote: >>> On Mon, Mar 18, 2024 at 12:41:48AM +0000, Pavel Begunkov wrote: >>>> io_uring_cmd_done() is called from the irq context and is considered to >>>> be irq safe, however that's not the case if the driver requires >>>> cancellations because io_uring_cmd_del_cancelable() could try to take >>>> the uring_lock mutex. >>>> >>>> Clean up the confusion, by deferring cancellation handling to >>>> locked task_work if we came into io_uring_cmd_done() from iowq >>>> or other IO_URING_F_UNLOCKED path. >>>> >>>> Signed-off-by: Pavel Begunkov >>>> --- >>>> io_uring/uring_cmd.c | 24 +++++++++++++++++------- >>>> 1 file changed, 17 insertions(+), 7 deletions(-) >>>> >>>> diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c >>>> index ec38a8d4836d..9590081feb2d 100644 >>>> --- a/io_uring/uring_cmd.c >>>> +++ b/io_uring/uring_cmd.c >>>> @@ -14,19 +14,18 @@ >>>> #include "rsrc.h"on #include "uring_cmd.h" >>>> -static void io_uring_cmd_del_cancelable(struct io_uring_cmd *cmd, >>>> - unsigned int issue_flags) >>>> +static void io_uring_cmd_del_cancelable(struct io_uring_cmd *cmd) >>>> { >>>> struct io_kiocb *req = cmd_to_io_kiocb(cmd); >>>> struct io_ring_ctx *ctx = req->ctx; >>>> + lockdep_assert_held(&ctx->uring_lock); >>>> + >>>> if (!(cmd->flags & IORING_URING_CMD_CANCELABLE)) >>>> return; >>>> cmd->flags &= ~IORING_URING_CMD_CANCELABLE; >>>> - io_ring_submit_lock(ctx, issue_flags); >>>> hlist_del(&req->hash_node); >>>> - io_ring_submit_unlock(ctx, issue_flags); >>>> } >>>> /* >>>> @@ -44,6 +43,9 @@ void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, >>>> struct io_kiocb *req = cmd_to_io_kiocb(cmd); >>>> struct io_ring_ctx *ctx = req->ctx; >>>> + if (WARN_ON_ONCE(ctx->flags & IORING_SETUP_IOPOLL)) >>>> + return; >>>> + >>> >>> This way limits cancelable command can't be used in iopoll context, and >>> it isn't reasonable, and supporting iopoll has been in ublk todo list, >>> especially single ring context is shared for both command and normal IO. >> >> That's something that can be solved when it's needed, and hence the >> warning so it's not missed. That would need del_cancelable on the >> ->iopoll side, but depends on the "leaving in cancel queue" >> problem resolution. > > The current code is actually working with iopoll, so adding the warning > can be one regression. Maybe someone has been using ublk with iopoll. Hmm, I don't see ->uring_cmd_iopoll implemented anywhere, and w/o it io_uring should fail the request: int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags) { ... if (ctx->flags & IORING_SETUP_IOPOLL) { if (!file->f_op->uring_cmd_iopoll) return -EOPNOTSUPP; issue_flags |= IO_URING_F_IOPOLL; } } Did I miss it somewhere? -- Pavel Begunkov