Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 28 Jan 2022 11:55:10 -0100
From:   Melissa Wen <mwen@igalia.com>
To:     Yongzhi Liu <lyz_cs@pku.edu.cn>
Cc:     emma@anholt.net, airlied@linux.ie, daniel@ffwll.ch,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2] drm/v3d: fix missing unlock
Message-ID: <20220128125510.idyai4bp3g5nbzd2@mail.igalia.com>
References: <20220126205726.phfikh7kn3lks5ib@mail.igalia.com>
 <1643278460-100473-1-git-send-email-lyz_cs@pku.edu.cn>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="g64nw4ibv7tj6mml"
Content-Disposition: inline
In-Reply-To: <1643278460-100473-1-git-send-email-lyz_cs@pku.edu.cn>
Precedence: bulk


--g64nw4ibv7tj6mml
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On 01/27, Yongzhi Liu wrote:
> [why]
> Unlock is needed on the error handling path to prevent dead lock.
> v3d_submit_cl_ioctl and v3d_submit_csd_ioctl is missing unlock.
>=20
> [how]
> Fix this by change goto target on the error handling path.
s/change/changing/g

I would just say: `Changing the goto to target an error handling path
that includes drm_gem_unlock reservations.`

and drop the explanation below

> As unlock is handle in fail_unreserve, i keep the failures
> handling around there. So the goto targets a place between
> `fail_unreserve:` and `fail:`.
>=20
> Signed-off-by: Yongzhi Liu <lyz_cs@pku.edu.cn>
> ---
>  drivers/gpu/drm/v3d/v3d_gem.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> index c7ed2e1..d9c7b39 100644
> --- a/drivers/gpu/drm/v3d/v3d_gem.c
> +++ b/drivers/gpu/drm/v3d/v3d_gem.c
> @@ -798,7 +798,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *dat=
a,
> =20
>  		if (!render->base.perfmon) {
>  			ret =3D -ENOENT;
> -			goto fail;
> +			goto v3d_unlock;
We usually use a `fail` prefix when handling failures.
A suggestion: `fail_perfmon` ?
>  		}
>  	}
> =20
> @@ -847,6 +847,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *dat=
a,
> =20
>  fail_unreserve:
>  	mutex_unlock(&v3d->sched_lock);
> +v3d_unlock:
>  	drm_gem_unlock_reservations(last_job->bo,
>  				    last_job->bo_count, &acquire_ctx);
>  fail:
> @@ -1027,7 +1028,7 @@ v3d_submit_csd_ioctl(struct drm_device *dev, void *=
data,
>  						     args->perfmon_id);
>  		if (!job->base.perfmon) {
>  			ret =3D -ENOENT;
> -			goto fail;
> +			goto v3d_unlock;
>  		}
>  	}
> =20
> @@ -1056,6 +1057,7 @@ v3d_submit_csd_ioctl(struct drm_device *dev, void *=
data,
> =20
>  fail_unreserve:
>  	mutex_unlock(&v3d->sched_lock);
> +v3d_unlock:
>  	drm_gem_unlock_reservations(clean_job->bo, clean_job->bo_count,
>  				    &acquire_ctx);
>  fail:

With these changes, you can include in the next version my r-b:
Reviewed-by: Melissa Wen <mwen@igalia.com>

> --=20
> 2.7.4
>=20

--g64nw4ibv7tj6mml
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=vq1L
-----END PGP SIGNATURE-----

--g64nw4ibv7tj6mml--