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Date:   Fri, 23 Jun 2023 09:48:31 +0200
From:   Andi Shyti <andi.shyti@linux.intel.com>
To:     Thomas =?iso-8859-15?Q?Hellstr=F6m?= 
        <thomas.hellstrom@linux.intel.com>
Cc:     Christian =?iso-8859-15?Q?K=F6nig?= <christian.koenig@amd.com>,
        Andi Shyti <andi.shyti@linux.intel.com>,
        intel-xe@lists.freedesktop.org,
        Andrey Grodzovsky <andrey.grodzovsky@amd.com>,
        Christian =?iso-8859-15?Q?K=F6nig?= 
        <ckoenig.leichtzumerken@gmail.com>,
        intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Huang Rui <ray.huang@amd.com>,
        dri-devel@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH 3/4] drm/ttm: Don't leak a resource on
 eviction error
Message-ID: <ZJVOTzorVVTvvF2z@ashyti-mobl2.lan>
References: <20230622101412.78426-1-thomas.hellstrom@linux.intel.com>
 <20230622101412.78426-4-thomas.hellstrom@linux.intel.com>
 <ZJRSyp7fT6VXpow7@ashyti-mobl2.lan>
 <3a089ebb-7389-3d3e-beb0-13a8d64eb04d@linux.intel.com>
 <196a7f74-66ac-1eae-4795-a42691f4793e@amd.com>
 <ef5d91b8-c68b-5edc-d611-6a4dbf55c945@linux.intel.com>
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Hi Christian and Thomas,

> > > > > diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> > > > > b/drivers/gpu/drm/ttm/ttm_bo.c
> > > > > index 615d30c4262d..89530f2a027f 100644
> > > > > --- a/drivers/gpu/drm/ttm/ttm_bo.c
> > > > > +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> > > > > @@ -462,14 +462,14 @@ static int ttm_bo_evict(struct
> > > > > ttm_buffer_object *bo,
> > > > > ????? ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
> > > > > ????? if (ret == -EMULTIHOP) {
> > > > > ????????? ret = ttm_bo_bounce_temp_buffer(bo, &evict_mem, ctx, &hop);
> > > > > -??????? if (ret) {
> > > > > -??????????? if (ret != -ERESTARTSYS && ret != -EINTR)
> > > > > -??????????????? pr_err("Buffer eviction failed\n");
> > > > > -??????????? ttm_resource_free(bo, &evict_mem);
> > > > > -??????????? goto out;
> > > > > -??????? }
> > > > > -??????? /* try and move to final place now. */
> > > > > -??????? goto bounce;
> > > > > +??????? if (!ret)
> > > > > +??????????? /* try and move to final place now. */
> > > > > +??????????? goto bounce;
> > > > As we are at this, can't we replace this with a while()? Goto's
> > > > used instead of a while loop are a fist in the eye...
> > > 
> > > I'm completely OK with that. this patch already did away with one of
> > > them. Let's hear Christian's opinion first, though.
> > 
> > I'm not a fan of that goto either, but could we somehow avoid the
> > while(1) ? E.g. something like do { } while (!ret) after handling the
> > multihop?
> 
> I think the construct that makes it most obvious what's happening, although
> it needs two tests for -EMULTIHOP is something like
> 
> do {
> ....
> ?? if (ret != -EMULTIHOP)
> ????? break;
> ?? ....
> } while (ret ==-EMULTIHOP);

even better :)

Thank you!
Andi