Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38;
Date:   Tue, 17 Oct 2023 20:55:02 +0200
From:   Michal =?utf-8?Q?Koutn=C3=BD?= <mkoutny@suse.com>
To:     Haitao Huang <haitao.huang@linux.intel.com>
Cc:     jarkko@kernel.org, dave.hansen@linux.intel.com, tj@kernel.org,
        linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
        x86@kernel.org, cgroups@vger.kernel.org, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
        sohil.mehta@intel.com, zhiquan1.li@intel.com,
        kristen@linux.intel.com, seanjc@google.com, zhanb@microsoft.com,
        anakrish@microsoft.com, mikko.ylinen@linux.intel.com,
        yangjie@microsoft.com
Subject: Re: [PATCH v5 01/18] cgroup/misc: Add per resource callbacks for CSS
 events
Message-ID: <k4hvow3juyelizqrlwdjmuu57kscvcwanu3xhpeuqnppynzrdu@hmxuvgefqpo5>
References: <20230923030657.16148-1-haitao.huang@linux.intel.com>
 <20230923030657.16148-2-haitao.huang@linux.intel.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="do7f6ref46fav4tn"
Content-Disposition: inline
In-Reply-To: <20230923030657.16148-2-haitao.huang@linux.intel.com>
Precedence: bulk


--do7f6ref46fav4tn
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Fri, Sep 22, 2023 at 08:06:40PM -0700, Haitao Huang <haitao.huang@linux.=
intel.com> wrote:
> @@ -276,10 +276,13 @@ static ssize_t misc_cg_max_write(struct kernfs_open=
_file *of, char *buf,
> =20
>  	cg =3D css_misc(of_css(of));
> =20
> -	if (READ_ONCE(misc_res_capacity[type]))
> +	if (READ_ONCE(misc_res_capacity[type])) {
>  		WRITE_ONCE(cg->res[type].max, max);
> -	else
> +		if (cg->res[type].max_write)
> +			cg->res[type].max_write(cg);
> +	} else {
>  		ret =3D -EINVAL;
>
> +	}

Is it time for a misc_cg_mutex? This given no synchronization guarantees
to implementors of max_write. (Alternatively, document it that the
callback must implement own synchronization.)


Thanks,
Michal

--do7f6ref46fav4tn
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----

iHUEABYKAB0WIQQpEWyjXuwGT2dDBqAGvrMr/1gcjgUCZS7YhAAKCRAGvrMr/1gc
jtZGAP9yG0GJSSTgY45EqfHcfkzqyBg2KvAFA7gx5WotIRHTkwD+Mo6bB7HpvmUH
8ZJECbI9T8hXKU0Ff2O/oEC4KwR3Mw8=
=5qrs
-----END PGP SIGNATURE-----

--do7f6ref46fav4tn--