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Message-ID: <06e1342e5bee87e53e4c43bf31572cda0910513d.camel@linux.intel.com>
Subject: Re: [Intel-xe] [PATCH v2 2/4] drm/ttm: Don't shadow the operation
 context
From:   Thomas =?ISO-8859-1?Q?Hellstr=F6m?= 
        <thomas.hellstrom@linux.intel.com>
To:     Christian =?ISO-8859-1?Q?K=F6nig?= 
        <ckoenig.leichtzumerken@gmail.com>, intel-xe@lists.freedesktop.org
Cc:     intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Roger He <Hongbo.He@amd.com>,
        dri-devel@lists.freedesktop.org,
        Christian =?ISO-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>
Date:   Mon, 26 Jun 2023 17:23:27 +0200
In-Reply-To: <88cbec2d2ae6329d44426cece4b558b7d83b1ff6.camel@linux.intel.com>
References: <20230626091450.14757-1-thomas.hellstrom@linux.intel.com>
         <20230626091450.14757-3-thomas.hellstrom@linux.intel.com>
         <8b22c855-c84d-4b56-c94b-a3a079ab3037@gmail.com>
         <88cbec2d2ae6329d44426cece4b558b7d83b1ff6.camel@linux.intel.com>
Organization: Intel Sweden AB, Registration Number: 556189-6027
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On Mon, 2023-06-26 at 17:18 +0200, Thomas Hellstr=C3=B6m wrote:
> On Mon, 2023-06-26 at 17:15 +0200, Christian K=C3=B6nig wrote:
> > Am 26.06.23 um 11:14 schrieb Thomas Hellstr=C3=B6m:
> > > ttm_bo_swapout() shadows the ttm operation context which may
> > > cause
> > > major confusion in driver callbacks when swapping out
> > > !TTM_PL_SYSTEM
> > > memory. Fix this by reusing the operation context argument to
> > > ttm_bo_swapout().
> > >=20
> > > Cc: "Christian K=C3=B6nig" <christian.koenig@amd.com>
> > > Cc: Roger He <Hongbo.He@amd.com>
> > > Cc: <dri-devel@lists.freedesktop.org>
> > > Cc: <intel-gfx@lists.freedesktop.org>
> > > Cc: <stable@vger.kernel.org> # v4.16+
> > > Fixes: dc947770cf34 ("drm/ttm: enable swapout for reserved BOs
> > > during allocation")
> > > Signed-off-by: Thomas Hellstr=C3=B6m
> > > <thomas.hellstrom@linux.intel.com>
> > > Acked-by: Matthew Brost <matthew.brost@intel.com>
> >=20
> > We intentionally didn't used the parameter here, but I absolutely
> > can't=20
> > figure out why.
> >=20
> > Feel free to add my rb, but let's give it some time upstream before
> > you=20
> > base anything on top of this. Just in case we missed something.
>=20
> Sure. Thanks for reviewing,

BTW, I'll remove the Fixes: tag as well.

/Thomas


> /Thomas
>=20
> >=20
> > Regards,
> > Christian.
> >=20
> > > ---
> > > =C2=A0 drivers/gpu/drm/ttm/ttm_bo.c | 3 +--
> > > =C2=A0 1 file changed, 1 insertion(+), 2 deletions(-)
> > >=20
> > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> > > b/drivers/gpu/drm/ttm/ttm_bo.c
> > > index bd5dae4d1624..615d30c4262d 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > @@ -1154,7 +1154,6 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > > *bo, struct ttm_operation_ctx *ctx,
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * Move to system cac=
hed
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 */
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (bo->resource->mem=
_type !=3D TTM_PL_SYSTEM) {
> > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0struct ttm_operation_ctx ctx =3D { false, false };
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0struct ttm_resource *evict_mem;
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0struct ttm_place hop;
> > > =C2=A0=20
> > > @@ -1164,7 +1163,7 @@ int ttm_bo_swapout(struct ttm_buffer_object
> > > *bo, struct ttm_operation_ctx *ctx,
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0if (unlikely(ret))
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
goto out;
> > > =C2=A0=20
> > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0ret =3D ttm_bo_handle_move_mem(bo, evict_mem, true,
> > > &ctx, &hop);
> > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0ret =3D ttm_bo_handle_move_mem(bo, evict_mem, true,
> > > ctx, &hop);
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0if (unlikely(ret !=3D 0)) {
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
WARN(ret =3D=3D -EMULTIHOP, "Unexpected
> > > multihop in swaput - likely driver bug.\n");
> > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
goto out;
> >=20
>=20