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Tue, 7 Jan 2025 08:45:06 +0000 (GMT) Message-ID: <263963d9-ac40-4f87-b38a-edb4202d294c@linux.ibm.com> Date: Tue, 7 Jan 2025 14:15:05 +0530 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6/8] nvme: fix queue freeze vs limits lock order To: Christoph Hellwig Cc: Jens Axboe , Damien Le Moal , Ming Lei , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, nbd@other.debian.org, linux-scsi@vger.kernel.org, usb-storage@lists.one-eyed-alien.net References: <20250107063120.1011593-1-hch@lst.de> <20250107063120.1011593-7-hch@lst.de> <96c48ba0-3db5-4504-a456-e57440aa1b56@linux.ibm.com> <20250107082224.GB15960@lst.de> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20250107082224.GB15960@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: M2dqWYWIBMLItYkJibPc5ndXAo2l1a2P X-Proofpoint-ORIG-GUID: M2dqWYWIBMLItYkJibPc5ndXAo2l1a2P X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxscore=0 adultscore=0 mlxlogscore=536 impostorscore=0 priorityscore=1501 clxscore=1015 lowpriorityscore=0 spamscore=0 suspectscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501070070 On 1/7/25 1:52 PM, Christoph Hellwig wrote: > On Tue, Jan 07, 2025 at 12:28:29PM +0530, Nilay Shroff wrote: >>> - blk_mq_freeze_queue(ns->disk->queue); >>> lim = queue_limits_start_update(ns->disk->queue); >>> nvme_set_ctrl_limits(ns->ctrl, &lim); >>> + >>> + blk_mq_freeze_queue(ns->disk->queue); >>> ret = queue_limits_commit_update(ns->disk->queue, &lim); >>> set_disk_ro(ns->disk, nvme_ns_is_readonly(ns, info)); >>> blk_mq_unfreeze_queue(ns->disk->queue); >> >> I think we should freeze queue before nvme_set_ctrl_limits(). > > Why? > The nvme_set_ctrl_limits() sets certain queue limits which are also used during IO processing. For instance, ->max_segment_size is used while submitting bio. Also, if we look at the code before your patch, nvme_set_ctrl_limits() is called when the queue is freezed. Thanks, --Nilay