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Date: Thu, 23 May 2024 14:13:21 +0200
From: Boris Brezillon <boris.brezillon@collabora.com>
To: =?UTF-8?B?QWRyacOhbg==?= Larumbe <adrian.larumbe@collabora.com>
Cc: Rob Herring <robh@kernel.org>, Steven Price <steven.price@arm.com>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard
 <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, David Airlie
 <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Sumit Semwal
 <sumit.semwal@linaro.org>, Christian =?UTF-8?B?S8O2bmln?=
 <christian.koenig@amd.com>, Dmitry Osipenko
 <dmitry.osipenko@collabora.com>, Zack Rusin <zack.rusin@broadcom.com>,
 kernel@collabora.com, dri-devel@lists.freedesktop.org,
 linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
 linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH v4 2/3] drm/lima: Fix dma_resv deadlock at drm object
 pin time
Message-ID: <20240523141321.52ea7224@collabora.com>
In-Reply-To: <20240523113236.432585-3-adrian.larumbe@collabora.com>
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	<20240523113236.432585-3-adrian.larumbe@collabora.com>
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On Thu, 23 May 2024 12:32:18 +0100
Adri=C3=A1n Larumbe <adrian.larumbe@collabora.com> wrote:

> Commit a78027847226 ("drm/gem: Acquire reservation lock in
> drm_gem_{pin/unpin}()") moved locking the DRM object's dma reservation to
> drm_gem_pin(), but Lima's pin callback kept calling drm_gem_shmem_pin,
> which also tries to lock the same dma_resv, leading to a double lock
> situation.
>=20
> As was already done for Panfrost in the previous commit, fix it by
> replacing drm_gem_shmem_pin() with its locked variant.
>=20
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> Cc: Boris Brezillon <boris.brezillon@collabora.com>
> Cc: Steven Price <steven.price@arm.com>
> Fixes: a78027847226 ("drm/gem: Acquire reservation lock in drm_gem_{pin/u=
npin}()")
> Signed-off-by: Adri=C3=A1n Larumbe <adrian.larumbe@collabora.com>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/lima/lima_gem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_=
gem.c
> index 7ea244d876ca..9bb997dbb4b9 100644
> --- a/drivers/gpu/drm/lima/lima_gem.c
> +++ b/drivers/gpu/drm/lima/lima_gem.c
> @@ -185,7 +185,7 @@ static int lima_gem_pin(struct drm_gem_object *obj)
>  	if (bo->heap_size)
>  		return -EINVAL;
> =20
> -	return drm_gem_shmem_pin(&bo->base);
> +	return drm_gem_shmem_pin_locked(&bo->base);
>  }
> =20
>  static int lima_gem_vmap(struct drm_gem_object *obj, struct iosys_map *m=
ap)