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Tue, 18 Nov 2025 06:56:11 +0000 (GMT) Message-ID: Date: Tue, 18 Nov 2025 12:26:10 +0530 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 v6 2/2] block: Remove queue freezing from several sysfs store callbacks To: Bart Van Assche , Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , Martin Wilck , Benjamin Marzinski , stable@vger.kernel.org, Hannes Reinecke , Damien Le Moal , Chaitanya Kulkarni References: <20251114210409.3123309-1-bvanassche@acm.org> <20251114210409.3123309-3-bvanassche@acm.org> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20251114210409.3123309-3-bvanassche@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: ANkC8AGbR9Jrdq8Nu-uTe-ou9HwPZqAv X-Authority-Analysis: v=2.4 cv=YqwChoYX c=1 sm=1 tr=0 ts=691c1891 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=SmKCfEfQzWduBHVzYMUA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: ANkC8AGbR9Jrdq8Nu-uTe-ou9HwPZqAv X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfX8EJrYltZs013 KbwG6hrl3bhmLU777j3A9y4GMZXoXJKeXqT7SoviOV5uQtWZxnauIiBlqWTj6r7e6YOUzAKrO82 4ASUAkQHqadzBpLS+OuMEDa70MaVI8S7+ZDd5Pe6MANCRSoYY22DeGt0/CEDDX5NGd/0rkpW8FZ SR82Sd3uPzj/UFyprXNWjxv0fS3vbfFsxZyB3XKcpt4HIBjJjzKhCoFECeHobv+kkxQhK5NwrDX TcGcpE22OpM+dUHwB3gOszU2hsD6nYTn45Kqfc93XEDZe/UbZWtMpkcitfUO+pWJigTu3DE/Rb2 G2l4LEoVLC4lwkAZkGacFaW7jwzewex37H16mj7wIWeTO8nl9tfjPmIVRqMNe8VmaTuYXTKfWQp 70OXojv1Gb4IUB0nhCD6Fhne4yu1jQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-17_04,2025-11-13_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 adultscore=0 bulkscore=0 phishscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 On 11/15/25 2:34 AM, Bart Van Assche wrote: > Freezing the request queue from inside sysfs store callbacks may cause a > deadlock in combination with the dm-multipath driver and the > queue_if_no_path option. Additionally, freezing the request queue slows > down system boot on systems where sysfs attributes are set synchronously. > > Fix this by removing the blk_mq_freeze_queue() / blk_mq_unfreeze_queue() > calls from the store callbacks that do not strictly need these callbacks. > Add the __data_racy annotation to request_queue.rq_timeout to suppress > KCSAN data race reports about the rq_timeout reads. > > This patch may cause a small delay in applying the new settings. > > For all the attributes affected by this patch, I/O will complete > correctly whether the old or the new value of the attribute is used. > > This patch affects the following sysfs attributes: > * io_poll_delay > * io_timeout > * nomerges > * read_ahead_kb > * rq_affinity Looks good to me: Reviewed-by: Nilay Shroff