On Fri, 29 Nov 2019 14:59:06 +0100
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> wrote:
> We don't want imported/exported BOs to be purges, as those are shared
> with other processes that might still use them. We should also refuse
> to export a BO if it's been marked purgeable or has already been purged.
>
> Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/panfrost/panfrost_drv.c | 19 ++++++++++++++++-
> drivers/gpu/drm/panfrost/panfrost_gem.c | 27 +++++++++++++++++++++++++
> 2 files changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 1c67ac434e10..751df975534f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -343,6 +343,7 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
> struct drm_panfrost_madvise *args = data;
> struct panfrost_device *pfdev = dev->dev_private;
> struct drm_gem_object *gem_obj;
> + int ret;
>
> gem_obj = drm_gem_object_lookup(file_priv, args->handle);
> if (!gem_obj) {
> @@ -350,6 +351,19 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
> return -ENOENT;
> }
>
> + /*
> + * We don't want to mark exported/imported BOs as purgeable: we're not
> + * the only owner in that case.
> + */
> + mutex_lock(&dev->object_name_lock);
> + if (gem_obj->dma_buf)
> + ret = -EINVAL;
> + else
> + ret = 0;
> +
> + if (ret)
> + goto out_unlock_object_name;
> +
> mutex_lock(&pfdev->shrinker_lock);
> args->retained = drm_gem_shmem_madvise(gem_obj, args->madv);
>
> @@ -364,8 +378,11 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
> }
> mutex_unlock(&pfdev->shrinker_lock);
>
> +out_unlock_object_name:
> + mutex_unlock(&dev->object_name_lock);
> +
> drm_gem_object_put_unlocked(gem_obj);
> - return 0;
> + return ret;
> }
>
> int panfrost_unstable_ioctl_check(void)
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
> index 92a95210a899..31d6417dd21c 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -99,6 +99,32 @@ void panfrost_gem_close(struct drm_gem_object *obj, struct drm_file *file_priv)
> spin_unlock(&priv->mm_lock);
> }
>
> +static struct dma_buf *
> +panfrost_gem_export(struct drm_gem_object *obj, int flags)
> +{
> + struct panfrost_gem_object *bo = to_panfrost_bo(obj);
> + int ret;
> +
> + /*
> + * We must make sure the BO has not been marked purgeable/purged before
> + * adding the mapping.
^s/adding the mapping/exporting it/
> + * Note that we don't need to protect this test with a lock because
> + * &drm_gem_object_funcs.export() is called with
> + * &drm_device.object_lock held, and panfrost_ioctl_madvise() takes
> + * this lock before calling drm_gem_shmem_madvise() (the function that
> + * modifies bo->base.madv).
> + */
> + if (bo->base.madv == PANFROST_MADV_WILLNEED)
> + ret = -EINVAL;
> + else
> + ret = 0;
> +
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return drm_gem_prime_export(obj, flags);
> +}
> +
> static int panfrost_gem_pin(struct drm_gem_object *obj)
> {
> if (to_panfrost_bo(obj)->is_heap)
> @@ -112,6 +138,7 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = {
> .open = panfrost_gem_open,
> .close = panfrost_gem_close,
> .print_info = drm_gem_shmem_print_info,
> + .export = panfrost_gem_export,
> .pin = panfrost_gem_pin,
> .unpin = drm_gem_shmem_unpin,
> .get_sg_table = drm_gem_shmem_get_sg_table,
