Re: [Intel-gfx] [PATCH 20/26] drm: use new iterator in drm_gem_fence_array_add_implicit v2

Daniel Vetter
2021-09-17T14:53:37Z

On Fri, Sep 17, 2021 at 02:35:07PM +0200, Christian König wrote:
> Simplifying the code a bit.
>
> v2: add missing rcu_read_lock()/unlock()
>
> Signed-off-by: Christian König <christian.koenig@amd.com>

This will be gone as soon as I can land the last conversion patches. Plus
it's always called with dma_resv_lock held.

I wouldn't bother tbh.
-Daniel

> ---
> drivers/gpu/drm/drm_gem.c | 34 ++++++++++++----------------------
> 1 file changed, 12 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 09c820045859..c2c41b668f40 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1340,31 +1340,21 @@ int drm_gem_fence_array_add_implicit(struct xarray *fence_array,
> struct drm_gem_object *obj,
> bool write)
> {
> - int ret;
> - struct dma_fence **fences;
> - unsigned int i, fence_count;
> -
> - if (!write) {
> - struct dma_fence *fence =
> - dma_resv_get_excl_unlocked(obj->resv);
> -
> - return drm_gem_fence_array_add(fence_array, fence);
> - }
> -
> - ret = dma_resv_get_fences(obj->resv, NULL,
> - &fence_count, &fences);
> - if (ret || !fence_count)
> - return ret;
> -
> - for (i = 0; i < fence_count; i++) {
> - ret = drm_gem_fence_array_add(fence_array, fences[i]);
> + struct dma_resv_iter cursor;
> + struct dma_fence *fence;
> + int ret = 0;
> +
> + rcu_read_lock();
> + dma_resv_iter_begin(&cursor, obj->resv, write);
> + dma_resv_for_each_fence_unlocked(&cursor, fence) {
> + rcu_read_unlock();
> + ret = drm_gem_fence_array_add(fence_array, fence);
> + rcu_read_lock();
> if (ret)
> break;
> }
> -
> - for (; i < fence_count; i++)
> - dma_fence_put(fences[i]);
> - kfree(fences);
> + dma_resv_iter_end(&cursor);
> + rcu_read_unlock();
> return ret;
> }
> EXPORT_SYMBOL(drm_gem_fence_array_add_implicit);
> --
> 2.25.1
>

--
Daniel Vetter
Software Engineer, Intel Corporation