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Thu, 14 Aug 2025 12:23:42 +0000 (GMT) Message-ID: <97b63163-a122-48f0-805a-a06cf792903f@linux.ibm.com> Date: Thu, 14 Aug 2025 17:53:41 +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 03/16] blk-mq: remove useless checkings from blk_mq_update_nr_requests() To: Yu Kuai , axboe@kernel.dk, yukuai3@huawei.com, bvanassche@acm.org, hare@suse.de, ming.lei@redhat.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com References: <20250814033522.770575-1-yukuai1@huaweicloud.com> <20250814033522.770575-4-yukuai1@huaweicloud.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: <20250814033522.770575-4-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=eaU9f6EH c=1 sm=1 tr=0 ts=689dd553 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=i0EeH86SAAAA:8 a=Ht_Kdwx_m2KS6Q0RhUUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: q75vbzp6xud_QhqAQ7zzK0-OtmOiOY6E X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODEzMDE2NyBTYWx0ZWRfX2qm4Bcdv8gsh 9hGWMhYBBJxrg2Pqz0Uzft1b3i3lXDrzJwTOne6AhRwAaddGNRssiPVnUmrLaDMAUPO9no64RSt ZQNKBNuNGx2Hiw8r/anu2ARs+y+O21TUiyPcKr6I/ARJs+pLxBXIy3Zfgt5cC6PUCBQfn/1BgCz XRyD/RjzcmoU1vqwGDNdBLTcI50tKLc4N/HFj8q/tDDqadjUC49vNec35xLInT66kbQZNv52mVz iWh4X28kTGXCQ5qknGZzrp4S2NbFjLris1CI0vsowu4UmoeBcC6jSaNZE1fNBcnj2tsx2Zq+e1V qR3jAZ1wLI0xAUdYP0B1l70+M5z/GhrbA7Gu3k/h4znFJv169GTXKuyXOCsO02X+oh7HGhlqlA0 2RKIVF79 X-Proofpoint-ORIG-GUID: q75vbzp6xud_QhqAQ7zzK0-OtmOiOY6E 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=2025-08-13_02,2025-08-14_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 phishscore=0 clxscore=1015 priorityscore=1501 spamscore=0 bulkscore=0 malwarescore=0 adultscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508130167 On 8/14/25 9:05 AM, Yu Kuai wrote: > From: Yu Kuai > > 1) queue_requests_store() is the only caller of > blk_mq_update_nr_requests(), where queue is already freezed, no need to > check mq_freeze_depth; > 2) q->tag_set must be set for request_based device, and queue_is_mq() is > already checked in blk_mq_queue_attr_visible(), no need to check > q->tag_set. > 3) During initialization, hctx->tags in initialized before queue > kobject, and during del_gendisk, queue kobject is deleted before > exiting hctx, hence checking hctx->tags is useless. > > Signed-off-by: Yu Kuai > --- > block/blk-mq.c | 11 +---------- > 1 file changed, 1 insertion(+), 10 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index b67d6c02eceb..3a219b7b3688 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -4921,24 +4921,15 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) > { > struct blk_mq_tag_set *set = q->tag_set; > struct blk_mq_hw_ctx *hctx; > - int ret; > + int ret = 0; > unsigned long i; > > - if (WARN_ON_ONCE(!q->mq_freeze_depth)) > - return -EINVAL; > - > - if (!set) > - return -EINVAL; > - > if (q->nr_requests == nr) > return 0; > > blk_mq_quiesce_queue(q); > > - ret = 0; > queue_for_each_hw_ctx(q, hctx, i) { > - if (!hctx->tags) > - continue; It's possible that hctx->tags is set to NULL in case no software queues are mapped to the hardware queue. So it seems that this check is valid. Please see blk_mq_map_swqueue(). Thanks, --Nilay