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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47f4635a63esm17501217f8f.9.2026.07.15.08.01.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 08:01:10 -0700 (PDT) Date: Wed, 15 Jul 2026 16:01:09 +0100 From: David Laight To: Tao Cui Cc: axboe@kernel.dk, tj@kernel.org, josef@toxicpanda.com, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Tao Cui Subject: Re: [PATCH] blk-throttle: fix divide-by-zero on legacy iops limit of 0 Message-ID: <20260715160109.51f553a7@pumpkin> In-Reply-To: <882fbac2-bd42-44a7-8fba-b387b3f0fb2b@linux.dev> References: <20260714103552.1335658-1-cui.tao@linux.dev> <20260714123754.7a88a65b@pumpkin> <882fbac2-bd42-44a7-8fba-b387b3f0fb2b@linux.dev> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Wed, 15 Jul 2026 20:44:19 +0800 Tao Cui wrote: > =E5=9C=A8 2026/7/14 19:37, David Laight =E5=86=99=E9=81=93: ... > >> tg_update_slice(tg, rw); > >> @@ -1386,7 +1391,8 @@ static ssize_t tg_set_conf(struct kernfs_open_fi= le *of, > >> if (is_u64) > >> *(u64 *)((void *)tg + of_cft(of)->private) =3D v; > >> else > >> - *(unsigned int *)((void *)tg + of_cft(of)->private) =3D v; > >> + *(unsigned int *)((void *)tg + of_cft(of)->private) =3D > >> + min_t(u64, v, UINT_MAX); =20 > >=20 > > The LHS casts look horrid - there has to be a nicer way to do that. > >=20 > > And you don't need min_t() a plain min() will be fine. > > =20 > Hi David, >=20 > Both done in v2 =E2=80=94 introduced a void *field local so the writes re= ad > *(u64 *)field / *(unsigned int *)field, and switched to > min(v, (u64)UINT_MAX). You don't need the cast either. David >=20 > Thanks, > Tao > > David > >=20 > >=20 > > =20 > >> =20 > >> tg_conf_updated(tg, false); > >> ret =3D 0; =20 > > =20 >=20