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Tue, 11 Nov 2025 08:39:57 +0000 (GMT) Message-ID: Date: Tue, 11 Nov 2025 14:09:56 +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: [PATCHv4 3/5] block: introduce alloc_sched_data and free_sched_data elevator methods To: yukuai@fnnas.com, linux-block@vger.kernel.org Cc: ming.lei@redhat.com, hch@lst.de, axboe@kernel.dk, yi.zhang@redhat.com, czhong@redhat.com, gjoyce@ibm.com References: <20251110081457.1006206-1-nilay@linux.ibm.com> <20251110081457.1006206-4-nilay@linux.ibm.com> Content-Language: en-US From: Nilay Shroff In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA4MDAyMiBTYWx0ZWRfX2Em0tbHm3s9x Y53tQ3x+L+XVXGSTFk7cFEQGpD1pkeVq24rxzU/44ul1nU99bQA6Ja0L1fOMTRxdb20SAB+VQaM W8TMw3jKkf/dWqp+sg7J0isNRKFoG8uPt3mtyYXi6NmshBibjq1mEL5+/Sj19G8anbzW+jzEv74 giwls8g/0jwr5jnCfK7JtHH+ZkFjZy5rhgIfOKXr5cVlqWh7ip0hWjst+HKCs0j2+NffTq+i1DZ pqLsaNZ9SGrlIUeasRjnythu38uF8chSTYJ+keQniONcugVEDlGL5iensVsuiIKdDipOrbEMa1o bjOPSy9Tz2hNBQiQiKNOKyvgiQryo4jtoYTLWUu4KuNbDEsCdQO4oC2kDZ73mGfl7461LGLrLCs ThF5o8Q1eZfy0EKv3L7vczPwk1KkNw== X-Authority-Analysis: v=2.4 cv=ZK3aWH7b c=1 sm=1 tr=0 ts=6912f662 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Ji6gVKsrb2LKOvRDE54A:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: C5pMpoHbIukNefFDo3tvpuFz8jBFwC3u X-Proofpoint-GUID: C5pMpoHbIukNefFDo3tvpuFz8jBFwC3u 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=2025-11-11_01,2025-11-11_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 phishscore=0 impostorscore=0 spamscore=0 bulkscore=0 adultscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511080022 On 11/11/25 12:50 PM, Yu Kuai wrote: >> +static inline int blk_mq_alloc_sched_data(struct request_queue *q, >> + struct elevator_type *e, void **data) >> +{ >> + if (e && e->ops.alloc_sched_data) { >> + *data = e->ops.alloc_sched_data(q); >> + if (!*data) >> + return -ENOMEM; >> + } >> + return 0; >> +} > I'm not strongly against this, but instead of the input parameter > as the output, why not return data directly? I feel this is more readable. > > Perhaps you're considering different cases that alloc_sched_data() method > is defined or not, when NULL is returned. And this can be solved by fold above > helper into caller directly, there is only one caller anyway. In patch 4: > > if (types && types->ops.alloc_sched_data) { > res->data = types->ops.alloc_sched_data(q); > if (!res->data) { > blk_mq_free_sched_tags(); > return -ENOMEM; > } > } > Yes this looks good and feasible, I will address this in next version. Thanks, --Nilay