linux-kernel - Re: [PATCH v2 3/4] drm/ttm: Don't leak a resource on eviction error

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Message-ID: <aa189924-795c-0bd0-1a85-b60445572153@gmail.com>
Date:   Mon, 26 Jun 2023 13:32:59 +0200
From:   Christian König <ckoenig.leichtzumerken@...il.com>
To:     Thomas Hellström 
        <thomas.hellstrom@...ux.intel.com>, intel-xe@...ts.freedesktop.org
Cc:     Andrey Grodzovsky <andrey.grodzovsky@....com>,
        Christian König <christian.koenig@....com>,
        Huang Rui <ray.huang@....com>, dri-devel@...ts.freedesktop.org,
        stable@...r.kernel.org, Nirmoy Das <nirmoy.das@...el.com>,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Andi Shyti <andi.shyti@...ux.intel.com>
Subject: Re: [PATCH v2 3/4] drm/ttm: Don't leak a resource on eviction error

Am 26.06.23 um 11:14 schrieb Thomas Hellström:
> On eviction errors other than -EMULTIHOP we were leaking a resource.
> Fix.
>
> v2:
> - Avoid yet another goto (Andi Shyti)
>
> Fixes: 403797925768 ("drm/ttm: Fix multihop assert on eviction.")
> Cc: Andrey Grodzovsky <andrey.grodzovsky@....com>
> Cc: Christian König <christian.koenig@....com>
> Cc: Christian Koenig <christian.koenig@....com>
> Cc: Huang Rui <ray.huang@....com>
> Cc: dri-devel@...ts.freedesktop.org
> Cc: <stable@...r.kernel.org> # v5.15+
> Signed-off-by: Thomas Hellström <thomas.hellstrom@...ux.intel.com>
> Reviewed-by: Nirmoy Das <nirmoy.das@...el.com> #v1

Reviewed-by: Christian König <christian.koenig@....com>

> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 22 +++++++++++-----------
>   1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 615d30c4262d..c0e3bbd21d3d 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -458,18 +458,18 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
>   		goto out;
>   	}
>   
> -bounce:
> -	ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
> -	if (ret == -EMULTIHOP) {
> +	do {
> +		ret = ttm_bo_handle_move_mem(bo, evict_mem, true, ctx, &hop);
> +		if (ret != -EMULTIHOP)
> +			break;
> +
>   		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;
> +	} while (!ret);
> +
> +	if (ret) {
> +		ttm_resource_free(bo, &evict_mem);
> +		if (ret != -ERESTARTSYS && ret != -EINTR)
> +			pr_err("Buffer eviction failed\n");
>   	}
>   out:
>   	return ret;