From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) (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 6E9FB7469 for ; Thu, 22 Feb 2024 08:32:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708590741; cv=none; b=AwAL3WQenE5UpZUcj1QVEzPHtc+6D6kP8wtDQMrrYbWDUG0nbD0nJ/CLQztPgN4yJ7N6GMw1jNFwWzfC6gDdhMa/1HeayQCY9CtBfaW2W0x96v0n/LbPLKVfxUYsiByCjPuoosdFtbNUvA76y38EDKbOsl7zsT9obRxJJPu4hZY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708590741; c=relaxed/simple; bh=L9L8UdAHgkw3u3z3JRXM7P1REEFXeO0sAapccYOXKUM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fMBFkcY//x4RUBORy1sX+wKBlCjhloQBvq1h0roUeVM1R86zey3+Buq1N15dju9wrdyV3pK4MQlCSWQl1VsPVyS0hwRRF1QKeDUJ95AdWu2/uKOtz1PtRtf81WXpggzQ652rP7PWCmoGjCIbp+x9SIogaN4G9xiSCCmiDlvuRTs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=WQ8wZRqx; arc=none smtp.client-ip=209.85.210.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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="WQ8wZRqx" Received: by mail-pf1-f178.google.com with SMTP id d2e1a72fcca58-6e46b5e7c43so2315591b3a.2 for ; Thu, 22 Feb 2024 00:32:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1708590740; x=1709195540; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc:subject:date:message-id:reply-to; bh=lMWItRQLuK9R7O/ER6wnV+LzSM/KkJ/vGjp2HMnJ18k=; b=WQ8wZRqxM5kOKcn3nMUBzQx5zGzQ6siOsRnPgJwlEymUcDtb7vpPVencdf3ZIzem7m nnS7JvViIv/na0ToqrfZR6yBrUHYaZEECKRBcLWwq/JS1I4Qkuu2TXpNVoaiO58N9GV1 jO9wXpa5S622BQVccHOLqJhssKltvJSqLueuqmiefPlSXktLxi887n5KqdlHAvMXJ303 TzFc/JFxZin2Zpoky+CUqkymp0Izz+khCsCOTcHD9cTNY/aDTU+Cjqcr4av8/4HES1Xg tbIrK4DoIPUpL9xe3/s6QarmxeQoV5USgr/RDDOIFaw9EWrl7SIgTTaai0lQcQkjxOXj kEqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708590740; x=1709195540; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=lMWItRQLuK9R7O/ER6wnV+LzSM/KkJ/vGjp2HMnJ18k=; b=QZbAjMEjoaB/kokDP1pbyeZlGBry/WBRo/HZ1StuwbR73QV/K8X0xCLBwX1HpM9Ggq /qUmTX43cI/9sAdlnZpExpLgDYvAV0pzVqoQsUMo4HPlnjjxubCJEj9IGhxt88XSR1by Raa5gHxDpKWlE5Dg4N2UoP9IdPbJY7kj93tEbOqKUMNgYLrSUIOT7voL6667raULucbV i4cjeuSjDDmo2gjGuLXYcstmxrV2FJCGr6g6fh6CyBqSL3ump1N4u1+b18l7SKUZkHPH m5YzoEHqgO3WWQP+2vuIm2YjqFDrXH8RjWQVJ2UG6O0cvlC2XVJKn5TboWBEPd/i6Vwu cn4Q== X-Forwarded-Encrypted: i=1; AJvYcCUyAJT8GR6q23KBPC0qe+VnYkVGNOE1xDHN/6JxYuOAw8QPG1Dq5eq4tb1njs+d8Q3f/UwijDAIvoz1k6lZv/U2DjnjgbuVilYRaaHy X-Gm-Message-State: AOJu0Yxm5vH1J6k/F6N7/EjlERvIX9NCbMVEF/y33fnLLO7fIqsmFTQU 8eF1HU8RrFZQRD2fIfAnn0virl49n74KeMH3Lv0IBaLryAbaJr9m+gU6cpT53gs= X-Google-Smtp-Source: AGHT+IEJ/ErXfRjDfnw+40qm4JkSBBudXUJ46+gZtyp3W2miWkvvqHN+J0Ed76vt6iRVz4gD9BMQbQ== X-Received: by 2002:a05:6a21:9207:b0:19e:9c32:6073 with SMTP id tl7-20020a056a21920700b0019e9c326073mr23295694pzb.12.1708590739628; Thu, 22 Feb 2024 00:32:19 -0800 (PST) Received: from localhost (dhcp-141-239-158-86.hawaiiantel.net. [141.239.158.86]) by smtp.gmail.com with ESMTPSA id b15-20020a170902d50f00b001d9aa663282sm9360917plg.266.2024.02.22.00.32.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Feb 2024 00:32:19 -0800 (PST) Sender: Tejun Heo Date: Wed, 21 Feb 2024 22:32:17 -1000 From: Tejun Heo To: Lai Jiangshan Cc: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, allen.lkml@gmail.com, kernel-team@meta.com Subject: Re: [PATCH 6/7] workqueue: Allow cancel_work_sync() and disable_work() from atomic contexts on BH work items Message-ID: References: <20240221174333.700197-1-tj@kernel.org> <20240221174333.700197-7-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hello, On Thu, Feb 22, 2024 at 12:36:29PM +0800, Lai Jiangshan wrote: > On Thu, Feb 22, 2024 at 1:43 AM Tejun Heo wrote: > > > @@ -4077,11 +4076,37 @@ static bool __flush_work(struct work_struct *work, bool from_cancel) > > > > rcu_read_lock(); > > pool = start_flush_work(work, &barr, from_cancel); > > + is_bh = pool && (pool->flags & POOL_BH); > > rcu_read_unlock(); > > if (!pool) > > return false; > > > > - wait_for_completion(&barr.done); > > + if (is_bh && from_cancel) { > > Can "*work_data_bits(work) & WORK_OFFQ_BH" be used here? > If so, the previous patch will not be needed. Hmm... yeah, if we test from_cancel first, we should know that the work item is offq and then can depend on OFFQ_BH. Maybe I'm missing something. Will try that. Thanks. -- tejun