Re: [Intel-gfx] [PATCH 17/26] drm/i915: use new iterator in i915_gem_object_wait_priority

Tvrtko Ursulin
2021-09-14T12:42:59Z

On 13/09/2021 14:16, Christian König wrote:
> Simplifying the code a bit.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_wait.c | 29 ++++--------------------
> 1 file changed, 5 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> index 13174541f6c8..e2173a55e527 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
> @@ -120,31 +120,12 @@ i915_gem_object_wait_priority(struct drm_i915_gem_object *obj,
> unsigned int flags,
> const struct i915_sched_attr *attr)
> {
> - struct dma_fence *excl;
> -
> - if (flags & I915_WAIT_ALL) {
> - struct dma_fence **shared;
> - unsigned int count, i;
> - int ret;
> -
> - ret = dma_resv_get_fences(obj->base.resv, &excl, &count,
> - &shared);
> - if (ret)
> - return ret;
> -
> - for (i = 0; i < count; i++) {
> - i915_gem_fence_wait_priority(shared[i], attr);
> - dma_fence_put(shared[i]);
> - }
> -
> - kfree(shared);
> - } else {
> - excl = dma_resv_get_excl_unlocked(obj->base.resv);
> - }
> + struct dma_resv_cursor cursor;
> + struct dma_fence *fence;
>
> - if (excl) {
> - i915_gem_fence_wait_priority(excl, attr);
> - dma_fence_put(excl);
> + dma_resv_for_each_fence_unlocked(obj->base.resv, &cursor,
> + flags & I915_WAIT_ALL, fence) {
> + i915_gem_fence_wait_priority(fence, attr);

Do you know if the RCU lock is actually held here? I tried following the
KMS code paths but got lost in core helpers and driver vfuncs.

Regards,

Tvrtko

> }
> return 0;
> }
>