From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 6234D1CEAA3; Wed, 13 Aug 2025 05:03:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755061409; cv=none; b=CebnsCLTOHsAVNhCgBv3Vv6EvEAnXFk/UDfWKXYwlxEzEw2U+4bdxF33XL5E1gqe38ytfpd7RVJwBs1Yy6BBpbzny+ok3BTtVsa8m+ASO8FDNmGb7H3/IygACskdP6a/By3YH1H0ff7cdmE1vL0x2hXJS3e2Tu5zLOFLciRmszA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755061409; c=relaxed/simple; bh=tGLCXaL5vF+LCtUsKT7SsgJORseZhc8FqciBJ0dqgxY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EwLvn9yHjQTM/kbLnnOEclNzc3CX9Wivw18R2jbj5qGP7MABsATUUHtK3KV6QyizavhVlfAiv/Sc8cWLWffVbWggnrR4F/9ExrLuqTQUd+GTh0cxeNIWosGXE3R06Oa9g17rCWYu3kaRYMk7MxwKWtvoAHni02PAntfbHDxa6C8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=h7oPEyh5; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="h7oPEyh5" Received: from pps.filterd (m0360083.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 57CNQNGT030080; Wed, 13 Aug 2025 05:03:12 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=v2yJLc JwV0DvmeGnG0NJR2ILb4sP3qpRQ/zNjH1IqBA=; b=h7oPEyh5ibEjooU63PjEs0 iIPDhOw+8QC9cCVNVeYsxwjXhgkiW1Og9tBO4BFGlnKQyUOxqMRV2KLhwFsU0W1t LVnBjRuNsINVVMv7t/+f8xcHjljzFwnzA59ZuGtbfXct9fYmLBqgI6rP7OGYk8y5 8/M1pll+S1sOnIFPDuGZDYau3R89YBuURRpNbhR8WiGwhfSIgA744SRSw4Fa8ixQ LppceA+Oqrh6wcMzepQfQrD3skf0YoEi5Trjm/oJepfm5+EA1+TvlbsjImiNtKaf MXQIbtYUbW2hZ35GvMIRxaPfjn5r6BmZefDSEfh+JfQXxTN0nabMGwslxWRj8aqw == Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48dwudams7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Aug 2025 05:03:12 +0000 (GMT) Received: from m0360083.ppops.net (m0360083.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 57D53BbU004484; Wed, 13 Aug 2025 05:03:11 GMT Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48dwudams4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Aug 2025 05:03:11 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 57D41siq025667; Wed, 13 Aug 2025 05:03:10 GMT Received: from smtprelay07.wdc07v.mail.ibm.com ([172.16.1.74]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 48ejvmdggw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 Aug 2025 05:03:10 +0000 Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay07.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 57D53AB231457862 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Aug 2025 05:03:10 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2D76958059; Wed, 13 Aug 2025 05:03:10 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A6B3A58058; Wed, 13 Aug 2025 05:03:07 +0000 (GMT) Received: from [9.61.63.67] (unknown [9.61.63.67]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 13 Aug 2025 05:03:07 +0000 (GMT) Message-ID: Date: Wed, 13 Aug 2025 10:33:00 +0530 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] block: restore default wbt enablement To: Julian Sun , linux-block@vger.kernel.org Cc: axboe@kernel.dk, ming.lei@redhat.com, Julian Sun , stable@vger.kernel.org References: <20250812154257.57540-1-sunjunchao@bytedance.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20250812154257.57540-1-sunjunchao@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODEyMDIyNCBTYWx0ZWRfX5V2ue0HMwuR5 PFS9jnAN56WMniPy0imsi3vgQc8fir4qojnXjOjrJef7PdutCkOGLUDtmLIGvxSJgJnmrIE2Rlh jdbSL4OViGr8HP+GVVne0D6Gr3rV+czKSjxTZAGsjGy50YS45nunKX9xH0Bsv2+enwWiHoPfYMs 8AuKAaRasyaMgY/G6WYTBwnekFirnfoXsfvIdaFLz/GDc0Jd+frvJFddQWtWo2GSyiUvgDzllSz l3vn3q++HZ1yCewWKSFTS86Nf+OXzMHtxsF0o70I744Wrd5KA4MhYVuymUF14twiW4fUJMr6DPU k6DQn4RXViJ80N8SbhMbW7al/YR8JUisEyXZiMigMq/nv2XU0xP4nl3qI2F+AAeSdspo3zEQF1s otN2T8s8 X-Authority-Analysis: v=2.4 cv=d/31yQjE c=1 sm=1 tr=0 ts=689c1c90 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=968KyxNXAAAA:8 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=qyw61lXL-B-xqPK-4asA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: xR-kUKshz68yBRlOtG81zVrFMIdN_khy X-Proofpoint-ORIG-GUID: HHK6-3W_pvTH_4gJNl6C7EelEolvZwKa X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-12_08,2025-08-11_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 suspectscore=0 impostorscore=0 priorityscore=1501 phishscore=0 spamscore=0 adultscore=0 bulkscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508120224 On 8/12/25 9:12 PM, Julian Sun wrote: > The commit 245618f8e45f ("block: protect wbt_lat_usec using > q->elevator_lock") protected wbt_enable_default() with > q->elevator_lock; however, it also placed wbt_enable_default() > before blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);, resulting > in wbt failing to be enabled. > > Moreover, the protection of wbt_enable_default() by q->elevator_lock > was removed in commit 78c271344b6f ("block: move wbt_enable_default() > out of queue freezing from sched ->exit()"), so we can directly fix > this issue by placing wbt_enable_default() after > blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);. > > Additionally, this issue also causes the inability to read the > wbt_lat_usec file, and the scenario is as follows: > > root@q:/sys/block/sda/queue# cat wbt_lat_usec > cat: wbt_lat_usec: Invalid argument > > root@q:/data00/sjc/linux# ls /sys/kernel/debug/block/sda/rqos > cannot access '/sys/kernel/debug/block/sda/rqos': No such file or directory > > root@q:/data00/sjc/linux# find /sys -name wbt > /sys/kernel/debug/tracing/events/wbt > > After testing with this patch, wbt can be enabled normally. > > Signed-off-by: Julian Sun > Cc: stable@vger.kernel.org > Fixes: 245618f8e45f ("block: protect wbt_lat_usec using q->elevator_lock") Looks good to me: Reviewed-by: Nilay Shroff