From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C4D34B04B3 for ; Thu, 6 Aug 2026 23:38:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059488; cv=none; b=cusMfNuPOCgy2AZyHXLsoi7sks8SX3dFOUSK3GhoQ08UB8eQJIVk2bLry6VSMRKe17fGMfw4uuF5AmnsXMjzg8e68p3WLmue1fbHTm5vbLKVj+zdvyDZoS8z7C7yZAZ1bCO/nA6H30nt9GAu/1WAMok0HevibhOdBA6T8Xp85kQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786059488; c=relaxed/simple; bh=ZjERn8tIuBhr7KfTTy47XfTh0wXT3VCkxZ/9yDbVBpE=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=RtaS6agOVjLCJMt7CjSfPkqkpOIdvX/ExgHhRG7rDWvEd58T61CjeWb+JqlyP+NJBcquGil0Y+C/nIPFCZ4E53EzMITMn8mJ5Ei5o6vA9COzvti8Lw99J8zJyFlSjMFz7tvc+UYkhuY5WGhEa3QN7NtY04NkBTq0MUuW/16l3Js= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GJmGkAq2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GJmGkAq2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC2A51F000E9; Thu, 6 Aug 2026 23:38:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786059487; bh=oAPtEbxbO6lhryFen453jc4BByN/BWCjEvbFliTvU6o=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=GJmGkAq2dFIbQgvpPTasm+iJYH0ry1V4nEgCG3eddyvH0MbbH/rjQWIh3nE0+5bSm GXGCm9/dqsxj/4Uu+UgTWFW0lFWackI5fP79wgHUNY5w7+W/auQjOzSy+Pd9+QYFWM xCRIsVKUnQ1KGfipq0TjNzpfyHYL0iFAiNMhcC+bRa/4TWCsmTmh44Bq3l/Z9zKw7S HknJgS+zTIvWfC/+d5Ieg/DlnrNj2O59SO6HYgB9dlAuqKKaSjRybo8jBxEGsAmUEq THTfCmtaeo3F9sN5LHkBW85aSCrorFvFzbT8bpjwi57Kl8eZ+6GCl+1GzthrxyhpUN MQIhhL2f0Sjwg== Message-ID: <8d2a968c-f57d-4757-afb3-b79ee1f14223@kernel.org> Date: Fri, 7 Aug 2026 07:38:03 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, Daeho Jeong Subject: Re: [f2fs-dev] [PATCH v2] f2fs: quiesce background threads during system suspend using PM notifier To: Daeho Jeong , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com References: <20260806170108.2100312-1-daeho43@gmail.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260806170108.2100312-1-daeho43@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/7/26 01:01, Daeho Jeong wrote: > From: Daeho Jeong > > During system suspend, a race condition can cause f2fs_gc and f2fs_discard > threads to call submit_bio() while the underlying block device (e.g., UFS) > is in Runtime PM suspend. Because Runtime PM worker threads are already > frozen during task freezing, the threads become trapped in > __bio_queue_enter() waiting on mq_freeze_wq, leading to a PM freezer > timeout. > > To prevent this deadlock, register a PM notifier to set SBI_IS_SUSPENDING > during PM_SUSPEND_PREPARE. Background GC and discard threads check this > flag and immediately stop issuing new bios, allowing them to enter a > freezable sleep state cleanly before process freezing begins. > > In addition, check freezing() as a fast path to stop issuing new I/O > when non-PM freezing (e.g. dm-snapshot or cgroup freezer) is requested. > > Signed-off-by: Daeho Jeong Reviewed-by: Chao Yu Thanks,