From: Daniel Vetter <daniel@ffwll.ch>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org,
linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org,
daniel@ffwll.ch
Subject: Re: [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout
Date: Fri, 17 Sep 2021 16:43:20 +0200 [thread overview]
Message-ID: <YUSpiHK7Dd1pF/Mq@phenom.ffwll.local> (raw)
In-Reply-To: <20210917123513.1106-6-christian.koenig@amd.com>
On Fri, Sep 17, 2021 at 02:34:52PM +0200, Christian König wrote:
> This makes the function much simpler since the complex
> retry logic is now handled elsewhere.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
> drivers/dma-buf/dma-resv.c | 68 ++++++--------------------------------
> 1 file changed, 10 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
> index 9b90bd9ac018..c7db553ab115 100644
> --- a/drivers/dma-buf/dma-resv.c
> +++ b/drivers/dma-buf/dma-resv.c
> @@ -569,74 +569,26 @@ long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr,
> unsigned long timeout)
> {
> long ret = timeout ? timeout : 1;
> - unsigned int seq, shared_count;
> + struct dma_resv_iter cursor;
> struct dma_fence *fence;
> - int i;
>
> -retry:
> - shared_count = 0;
> - seq = read_seqcount_begin(&obj->seq);
> rcu_read_lock();
I missed this in my previous conversion reviews, but pls move the
rcu_read_lock into the iterator. That should simplify the flow in all of
these quite a bit more, and since the iter_next_unlocked grabs a full
reference for the iteration body we really don't need that protected by
rcu.
We can't toss rcu protection for dma_resv anytime soon (if ever), but we
can at least make it an implementation detail.
> - i = -1;
> -
> - fence = dma_resv_excl_fence(obj);
> - if (fence && !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
> - if (!dma_fence_get_rcu(fence))
> - goto unlock_retry;
> + dma_resv_iter_begin(&cursor, obj, wait_all);
> + dma_resv_for_each_fence_unlocked(&cursor, fence) {
> + rcu_read_unlock();
>
> - if (dma_fence_is_signaled(fence)) {
> - dma_fence_put(fence);
> - fence = NULL;
> + ret = dma_fence_wait_timeout(fence, intr, ret);
> + if (ret <= 0) {
> + dma_resv_iter_end(&cursor);
> + return ret;
> }
>
> - } else {
> - fence = NULL;
> - }
> -
> - if (wait_all) {
> - struct dma_resv_list *fobj = dma_resv_shared_list(obj);
> -
> - if (fobj)
> - shared_count = fobj->shared_count;
> -
> - for (i = 0; !fence && i < shared_count; ++i) {
> - struct dma_fence *lfence;
> -
> - lfence = rcu_dereference(fobj->shared[i]);
> - if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
> - &lfence->flags))
> - continue;
> -
> - if (!dma_fence_get_rcu(lfence))
> - goto unlock_retry;
> -
> - if (dma_fence_is_signaled(lfence)) {
> - dma_fence_put(lfence);
> - continue;
> - }
> -
> - fence = lfence;
> - break;
> - }
> + rcu_read_lock();
> }
> -
> + dma_resv_iter_end(&cursor);
> rcu_read_unlock();
> - if (fence) {
> - if (read_seqcount_retry(&obj->seq, seq)) {
> - dma_fence_put(fence);
> - goto retry;
> - }
>
> - ret = dma_fence_wait_timeout(fence, intr, ret);
> - dma_fence_put(fence);
> - if (ret > 0 && wait_all && (i + 1 < shared_count))
> - goto retry;
> - }
> return ret;
> -
> -unlock_retry:
> - rcu_read_unlock();
> - goto retry;
I think we still have the same semantics, and it's so much tidier.
With the rcu_read_unlock stuff into iterators (also applies to previous
two patches):
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> }
> EXPORT_SYMBOL_GPL(dma_resv_wait_timeout);
>
> --
> 2.25.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2021-09-17 14:43 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 12:34 Deploying new iterator interface for dma-buf Christian König
2021-09-17 12:34 ` [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Christian König
2021-09-17 13:23 ` Daniel Vetter
2021-09-20 8:43 ` [Intel-gfx] " Tvrtko Ursulin
2021-09-20 10:09 ` Christian König
2021-09-20 10:26 ` Tvrtko Ursulin
2021-09-17 12:34 ` [PATCH 02/26] dma-buf: add dma_resv_for_each_fence Christian König
2021-09-17 13:27 ` Daniel Vetter
2021-09-17 14:30 ` Daniel Vetter
2021-09-17 12:34 ` [PATCH 03/26] dma-buf: use new iterator in dma_resv_copy_fences Christian König
2021-09-17 14:35 ` Daniel Vetter
2021-09-20 7:23 ` Christian König
2021-09-17 12:34 ` [PATCH 04/26] dma-buf: use new iterator in dma_resv_get_fences v2 Christian König
2021-09-17 14:39 ` Daniel Vetter
2021-09-17 12:34 ` [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout Christian König
2021-09-17 14:43 ` Daniel Vetter [this message]
2021-09-20 7:27 ` Christian König
2021-09-17 12:34 ` [PATCH 06/26] dma-buf: use new iterator in dma_resv_test_signaled Christian König
2021-09-17 14:45 ` Daniel Vetter
2021-09-17 12:34 ` [PATCH 07/26] drm/ttm: use the new iterator in ttm_bo_flush_all_fences Christian König
2021-09-17 14:50 ` Daniel Vetter
2021-09-17 12:34 ` [PATCH 08/26] drm/amdgpu: use the new iterator in amdgpu_sync_resv Christian König
2021-09-17 12:34 ` [PATCH 09/26] drm/amdgpu: use new iterator in amdgpu_ttm_bo_eviction_valuable Christian König
2021-09-17 12:34 ` [PATCH 10/26] drm/msm: use new iterator in msm_gem_describe Christian König
2021-09-17 12:34 ` [PATCH 11/26] drm/radeon: use new iterator in radeon_sync_resv Christian König
2021-09-17 12:34 ` [PATCH 12/26] drm/scheduler: use new iterator in drm_sched_job_add_implicit_dependencies v2 Christian König
2021-09-17 14:52 ` Daniel Vetter
2021-11-15 14:03 ` Sascha Hauer
2021-11-15 14:08 ` Daniel Vetter
2021-11-15 20:32 ` Christian König
2021-11-16 7:56 ` Sascha Hauer
2021-09-17 12:35 ` [PATCH 13/26] drm/i915: use the new iterator in i915_gem_busy_ioctl Christian König
2021-09-20 8:45 ` [Intel-gfx] " Tvrtko Ursulin
2021-09-20 10:13 ` Christian König
2021-09-20 10:33 ` Tvrtko Ursulin
2021-09-21 9:41 ` Christian König
2021-09-21 13:10 ` Tvrtko Ursulin
2021-09-17 12:35 ` [PATCH 14/26] drm/i915: use the new iterator in i915_sw_fence_await_reservation v3 Christian König
2021-09-20 8:45 ` [Intel-gfx] " Tvrtko Ursulin
2021-09-20 8:47 ` Tvrtko Ursulin
2021-09-20 10:14 ` Christian König
2021-09-17 12:35 ` [PATCH 15/26] drm/i915: use the new iterator in i915_request_await_object v2 Christian König
2021-09-17 12:35 ` [PATCH 16/26] drm/i915: use new iterator in i915_gem_object_wait_reservation v2 Christian König
2021-09-20 10:00 ` [Intel-gfx] " Tvrtko Ursulin
2021-09-21 17:35 ` Christian König
2021-09-17 12:35 ` [PATCH 17/26] drm/i915: use new iterator in i915_gem_object_wait_priority v2 Christian König
2021-09-17 12:35 ` [PATCH 18/26] drm/i915: use new iterator in i915_gem_object_last_write_engine v2 Christian König
2021-09-17 12:35 ` [PATCH 19/26] drm/i915: use new cursor in intel_prepare_plane_fb v2 Christian König
2021-09-17 12:35 ` [PATCH 20/26] drm: use new iterator in drm_gem_fence_array_add_implicit v2 Christian König
2021-09-17 14:53 ` Daniel Vetter
2021-09-20 7:31 ` Christian König
2021-09-17 12:35 ` [PATCH 21/26] drm: use new iterator in drm_gem_plane_helper_prepare_fb v2 Christian König
2021-09-17 14:55 ` Daniel Vetter
2021-09-20 7:35 ` Christian König
2021-09-17 12:35 ` [PATCH 22/26] drm/nouveau: use the new iterator in nouveau_fence_sync Christian König
2021-09-17 12:35 ` [PATCH 23/26] drm/nouveau: use the new interator in nv50_wndw_prepare_fb v2 Christian König
2021-09-17 12:35 ` [PATCH 24/26] drm/etnaviv: use new iterator in etnaviv_gem_describe Christian König
2021-09-17 12:35 ` [PATCH 25/26] drm/etnaviv: replace dma_resv_get_excl_unlocked Christian König
2021-09-17 12:35 ` [PATCH 26/26] dma-buf: nuke dma_resv_get_excl_unlocked Christian König
2021-09-17 14:56 ` Daniel Vetter
-- strict thread matches above, loose matches on Subject: below --
2021-09-22 9:10 Deploying new iterator interface for dma-buf Christian König
2021-09-22 9:10 ` [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout Christian König
2021-09-21 17:36 [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v3 Christian König
2021-09-21 17:36 ` [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout Christian König
2021-09-16 11:30 Deploying new iterator interface for dma-buf Christian König
2021-09-16 11:30 ` [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout Christian König
2021-09-13 13:16 Deploying new iterator interface for dma-buf Christian König
2021-09-13 13:16 ` [PATCH 05/26] dma-buf: use new iterator in dma_resv_wait_timeout Christian König
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