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References: <20230521205112.150206-1-dmitry.osipenko@collabora.com> <20230521205112.150206-7-dmitry.osipenko@collabora.com>
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From:   Emil Velikov <emil.l.velikov@gmail.com>
Date:   Mon, 22 May 2023 14:02:19 +0100
Message-ID: <CACvgo52QvmZw5k_9dmBHPB25rTdLZJzVG_vNFr8or+3f5sVO=Q@mail.gmail.com>
Subject: Re: [PATCH v3 6/6] drm/shmem-helper: Switch to reservation lock
To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     Sumit Semwal <sumit.semwal@linaro.org>,
        =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        Liam Mark <lmark@codeaurora.org>,
        Brian Starkey <Brian.Starkey@arm.com>,
        John Stultz <jstultz@google.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Tomi Valkeinen <tomba@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Tomasz Figa <tfiga@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
        linux-tegra@vger.kernel.org, kernel@collabora.com
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Hi Dmitry,

Saw v3 fly by, so I had a quick look. Original RB still stands,
although I noticed a couple of non-blocking nitpicks.

On Sun, 21 May 2023 at 22:00, Dmitry Osipenko
<dmitry.osipenko@collabora.com> wrote:

> -static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
> +static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
>  {

Should this getter have a dma_resv_assert_held(shmem->base.resv); like
it's put brethren?


> -void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
> +static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
> +{
> +       int ret;
> +
> +       dma_resv_assert_held(shmem->base.resv);
> +
> +       ret = drm_gem_shmem_get_pages(shmem);
> +
> +       return ret;

With the assert_held in the getter, it would be less confusing to
inline this and the unpin_locked functions.

> +}
> +
> +static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
>  {
> -       mutex_lock(&shmem->pages_lock);
> -       drm_gem_shmem_put_pages_locked(shmem);
> -       mutex_unlock(&shmem->pages_lock);
> +       dma_resv_assert_held(shmem->base.resv);
> +
> +       drm_gem_shmem_put_pages(shmem);

Side note: the putter has an assert_held so the extra one here seems quite odd.

As said at the top - with or w/o these nitpicks, the original RB still stands.

HTH o/
-Emil