From: "Christian König" <ckoenig.leichtzumerken@gmail.com> To: linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org Cc: daniel@ffwll.ch Subject: [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Date: Fri, 17 Sep 2021 14:34:48 +0200 [thread overview] Message-ID: <20210917123513.1106-2-christian.koenig@amd.com> (raw) In-Reply-To: <20210917123513.1106-1-christian.koenig@amd.com> Abstract the complexity of iterating over all the fences in a dma_resv object. The new loop handles the whole RCU and retry dance and returns only fences where we can be sure we grabbed the right one. v2: fix accessing the shared fences while they might be freed, improve kerneldoc, rename _cursor to _iter, add dma_resv_iter_is_exclusive, add dma_resv_iter_begin/end Signed-off-by: Christian König <christian.koenig@amd.com> --- drivers/dma-buf/dma-resv.c | 61 +++++++++++++++++++++++++++ include/linux/dma-resv.h | 84 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 145 insertions(+) diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 84fbe60629e3..3e77cad2c9d4 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -323,6 +323,67 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence) } EXPORT_SYMBOL(dma_resv_add_excl_fence); +/** + * dma_resv_iter_walk_unlocked - walk over fences in a dma_resv obj + * @cursor: cursor to record the current position + * @first: if we should start over + * + * Return all the fences in the dma_resv object which are not yet signaled. + * The returned fence has an extra local reference so will stay alive. + * If a concurrent modify is detected the whole iterration is started over again. + */ +struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, + bool first) +{ + struct dma_resv *obj = cursor->obj; + + first |= read_seqcount_retry(&obj->seq, cursor->seq); + do { + /* Drop the reference from the previous round */ + dma_fence_put(cursor->fence); + + cursor->is_first = first; + if (first) { + cursor->seq = read_seqcount_begin(&obj->seq); + cursor->index = -1; + cursor->fences = dma_resv_shared_list(obj); + + cursor->fence = dma_resv_excl_fence(obj); + if (cursor->fence && + test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, + &cursor->fence->flags)) + cursor->fence = NULL; + } else { + cursor->fence = NULL; + } + + if (cursor->fence) { + cursor->fence = dma_fence_get_rcu(cursor->fence); + } else if (cursor->all_fences && cursor->fences) { + struct dma_resv_list *fences = cursor->fences; + + while (++cursor->index < fences->shared_count) { + cursor->fence = rcu_dereference( + fences->shared[cursor->index]); + if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, + &cursor->fence->flags)) + break; + } + if (cursor->index < fences->shared_count) + cursor->fence = + dma_fence_get_rcu(cursor->fence); + else + cursor->fence = NULL; + } + + /* For the eventually next round */ + first = true; + } while (read_seqcount_retry(&obj->seq, cursor->seq)); + + return cursor->fence; +} +EXPORT_SYMBOL_GPL(dma_resv_iter_walk_unlocked); + /** * dma_resv_copy_fences - Copy all fences from src to dst. * @dst: the destination reservation object diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 9100dd3dc21f..693d16117153 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -149,6 +149,90 @@ struct dma_resv { struct dma_resv_list __rcu *fence; }; +/** + * struct dma_resv_iter - current position into the dma_resv fences + * + * Don't touch this directly in the driver, use the accessor function instead. + */ +struct dma_resv_iter { + /** @obj: The dma_resv object we iterate over */ + struct dma_resv *obj; + + /** @all_fences: If all fences should be returned */ + bool all_fences; + + /** @fence: the currently handled fence */ + struct dma_fence *fence; + + /** @seq: sequence number to check for modifications */ + unsigned int seq; + + /** @index: index into the shared fences */ + unsigned int index; + + /** @fences: the shared fences */ + struct dma_resv_list *fences; + + /** @is_first: true if this is the first returned fence */ + bool is_first; +}; + +struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, + bool first); + +/** + * dma_resv_iter_begin - initialize a dma_resv_iter object + * @cursor: The dma_resv_iter object to initialize + * @obj: The dma_resv object which we want to iterator over + * @all_fences: If all fences should be returned or just the exclusive one + */ +static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor, + struct dma_resv *obj, + bool all_fences) +{ + cursor->obj = obj; + cursor->all_fences = all_fences; + cursor->fence = NULL; +} + +/** + * dma_resv_iter_end - cleanup a dma_resv_iter object + * @cursor: the dma_resv_iter object which should be cleaned up + * + * Make sure that the reference to the fence in the cursor is properly + * dropped. + */ +static inline void dma_resv_iter_end(struct dma_resv_iter *cursor) +{ + dma_fence_put(cursor->fence); +} + +/** + * dma_resv_iter_is_exclusive - test if the current fence is the exclusive one + * @cursor: the cursor of the current position + * + * Returns true if the currently returned fence is the exclusive one. + */ +static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor) +{ + return cursor->index == -1; +} + +/** + * dma_resv_for_each_fence_unlocked - unlocked fence iterator + * @cursor: a struct dma_resv_iter pointer + * @fence: the current fence + * + * Iterate over the fences in a struct dma_resv object without holding the + * dma_resv::lock. The RCU read side lock must be hold when using this, but can + * be dropped and re-taken as necessary inside the loop. The cursor needs to be + * initialized with dma_resv_iter_begin_unlocked() and cleaned up with + * dma_resv_iter_end_unlocked(). + */ +#define dma_resv_for_each_fence_unlocked(cursor, fence) \ + for (fence = dma_resv_iter_walk_unlocked(cursor, true); \ + fence; fence = dma_resv_iter_walk_unlocked(cursor, false)) + #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base) -- 2.25.1
WARNING: multiple messages have this Message-ID
From: "Christian König" <ckoenig.leichtzumerken@gmail.com> To: linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org Cc: daniel@ffwll.ch Subject: [Intel-gfx] [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Date: Fri, 17 Sep 2021 14:34:48 +0200 [thread overview] Message-ID: <20210917123513.1106-2-christian.koenig@amd.com> (raw) In-Reply-To: <20210917123513.1106-1-christian.koenig@amd.com> Abstract the complexity of iterating over all the fences in a dma_resv object. The new loop handles the whole RCU and retry dance and returns only fences where we can be sure we grabbed the right one. v2: fix accessing the shared fences while they might be freed, improve kerneldoc, rename _cursor to _iter, add dma_resv_iter_is_exclusive, add dma_resv_iter_begin/end Signed-off-by: Christian König <christian.koenig@amd.com> --- drivers/dma-buf/dma-resv.c | 61 +++++++++++++++++++++++++++ include/linux/dma-resv.h | 84 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 145 insertions(+) diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 84fbe60629e3..3e77cad2c9d4 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -323,6 +323,67 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence) } EXPORT_SYMBOL(dma_resv_add_excl_fence); +/** + * dma_resv_iter_walk_unlocked - walk over fences in a dma_resv obj + * @cursor: cursor to record the current position + * @first: if we should start over + * + * Return all the fences in the dma_resv object which are not yet signaled. + * The returned fence has an extra local reference so will stay alive. + * If a concurrent modify is detected the whole iterration is started over again. + */ +struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, + bool first) +{ + struct dma_resv *obj = cursor->obj; + + first |= read_seqcount_retry(&obj->seq, cursor->seq); + do { + /* Drop the reference from the previous round */ + dma_fence_put(cursor->fence); + + cursor->is_first = first; + if (first) { + cursor->seq = read_seqcount_begin(&obj->seq); + cursor->index = -1; + cursor->fences = dma_resv_shared_list(obj); + + cursor->fence = dma_resv_excl_fence(obj); + if (cursor->fence && + test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, + &cursor->fence->flags)) + cursor->fence = NULL; + } else { + cursor->fence = NULL; + } + + if (cursor->fence) { + cursor->fence = dma_fence_get_rcu(cursor->fence); + } else if (cursor->all_fences && cursor->fences) { + struct dma_resv_list *fences = cursor->fences; + + while (++cursor->index < fences->shared_count) { + cursor->fence = rcu_dereference( + fences->shared[cursor->index]); + if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, + &cursor->fence->flags)) + break; + } + if (cursor->index < fences->shared_count) + cursor->fence = + dma_fence_get_rcu(cursor->fence); + else + cursor->fence = NULL; + } + + /* For the eventually next round */ + first = true; + } while (read_seqcount_retry(&obj->seq, cursor->seq)); + + return cursor->fence; +} +EXPORT_SYMBOL_GPL(dma_resv_iter_walk_unlocked); + /** * dma_resv_copy_fences - Copy all fences from src to dst. * @dst: the destination reservation object diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 9100dd3dc21f..693d16117153 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -149,6 +149,90 @@ struct dma_resv { struct dma_resv_list __rcu *fence; }; +/** + * struct dma_resv_iter - current position into the dma_resv fences + * + * Don't touch this directly in the driver, use the accessor function instead. + */ +struct dma_resv_iter { + /** @obj: The dma_resv object we iterate over */ + struct dma_resv *obj; + + /** @all_fences: If all fences should be returned */ + bool all_fences; + + /** @fence: the currently handled fence */ + struct dma_fence *fence; + + /** @seq: sequence number to check for modifications */ + unsigned int seq; + + /** @index: index into the shared fences */ + unsigned int index; + + /** @fences: the shared fences */ + struct dma_resv_list *fences; + + /** @is_first: true if this is the first returned fence */ + bool is_first; +}; + +struct dma_fence *dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor, + bool first); + +/** + * dma_resv_iter_begin - initialize a dma_resv_iter object + * @cursor: The dma_resv_iter object to initialize + * @obj: The dma_resv object which we want to iterator over + * @all_fences: If all fences should be returned or just the exclusive one + */ +static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor, + struct dma_resv *obj, + bool all_fences) +{ + cursor->obj = obj; + cursor->all_fences = all_fences; + cursor->fence = NULL; +} + +/** + * dma_resv_iter_end - cleanup a dma_resv_iter object + * @cursor: the dma_resv_iter object which should be cleaned up + * + * Make sure that the reference to the fence in the cursor is properly + * dropped. + */ +static inline void dma_resv_iter_end(struct dma_resv_iter *cursor) +{ + dma_fence_put(cursor->fence); +} + +/** + * dma_resv_iter_is_exclusive - test if the current fence is the exclusive one + * @cursor: the cursor of the current position + * + * Returns true if the currently returned fence is the exclusive one. + */ +static inline bool dma_resv_iter_is_exclusive(struct dma_resv_iter *cursor) +{ + return cursor->index == -1; +} + +/** + * dma_resv_for_each_fence_unlocked - unlocked fence iterator + * @cursor: a struct dma_resv_iter pointer + * @fence: the current fence + * + * Iterate over the fences in a struct dma_resv object without holding the + * dma_resv::lock. The RCU read side lock must be hold when using this, but can + * be dropped and re-taken as necessary inside the loop. The cursor needs to be + * initialized with dma_resv_iter_begin_unlocked() and cleaned up with + * dma_resv_iter_end_unlocked(). + */ +#define dma_resv_for_each_fence_unlocked(cursor, fence) \ + for (fence = dma_resv_iter_walk_unlocked(cursor, true); \ + fence; fence = dma_resv_iter_walk_unlocked(cursor, false)) + #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base) -- 2.25.1
next prev parent reply other threads:[~2021-09-17 12:35 UTC|newest] Thread overview: 116+ 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 ` [Intel-gfx] " Christian König 2021-09-17 12:34 ` Christian König [this message] 2021-09-17 12:34 ` [Intel-gfx] [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Christian König 2021-09-17 13:23 ` Daniel Vetter 2021-09-17 13:23 ` [Intel-gfx] " Daniel Vetter 2021-09-20 8:43 ` 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 13:27 ` Daniel Vetter 2021-09-17 13:27 ` [Intel-gfx] " Daniel Vetter 2021-09-17 14:30 ` 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:35 ` Daniel Vetter 2021-09-17 14:35 ` [Intel-gfx] " Daniel Vetter 2021-09-20 7:23 ` Christian König 2021-09-20 7:23 ` [Intel-gfx] " 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:39 ` Daniel Vetter 2021-09-17 14:39 ` [Intel-gfx] " 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:43 ` Daniel Vetter 2021-09-17 14:43 ` [Intel-gfx] " Daniel Vetter 2021-09-20 7:27 ` Christian König 2021-09-20 7:27 ` [Intel-gfx] " 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:45 ` Daniel Vetter 2021-09-17 14:45 ` [Intel-gfx] " 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:50 ` Daniel Vetter 2021-09-17 14:50 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 12:34 ` [Intel-gfx] " Christian König 2021-09-17 14:52 ` Daniel Vetter 2021-09-17 14:52 ` [Intel-gfx] " Daniel Vetter 2021-11-15 14:03 ` Sascha Hauer 2021-11-15 14:03 ` Sascha Hauer 2021-11-15 14:03 ` [Intel-gfx] " Sascha Hauer 2021-11-15 14:08 ` Daniel Vetter 2021-11-15 14:08 ` [Intel-gfx] " Daniel Vetter 2021-11-15 14:08 ` Daniel Vetter 2021-11-15 20:32 ` Christian König 2021-11-15 20:32 ` Christian König 2021-11-15 20:32 ` [Intel-gfx] " Christian König 2021-11-16 7:56 ` Sascha Hauer 2021-11-16 7:56 ` [Intel-gfx] " Sascha Hauer 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 2021-09-17 12:35 ` [Intel-gfx] " Christian König 2021-09-20 8:45 ` 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 2021-09-17 12:35 ` [Intel-gfx] " Christian König 2021-09-20 8:45 ` 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 ` [Intel-gfx] " Christian König 2021-09-17 12:35 ` [PATCH 16/26] drm/i915: use new iterator in i915_gem_object_wait_reservation v2 Christian König 2021-09-17 12:35 ` [Intel-gfx] " Christian König 2021-09-20 10:00 ` 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 12:35 ` [Intel-gfx] " Christian König 2021-09-17 14:53 ` Daniel Vetter 2021-09-17 14:53 ` [Intel-gfx] " Daniel Vetter 2021-09-20 7:31 ` Christian König 2021-09-20 7:31 ` [Intel-gfx] " 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 12:35 ` [Intel-gfx] " Christian König 2021-09-17 14:55 ` Daniel Vetter 2021-09-17 14:55 ` [Intel-gfx] " Daniel Vetter 2021-09-20 7:35 ` Christian König 2021-09-20 7:35 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " 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 ` [Intel-gfx] " Christian König 2021-09-17 12:35 ` [PATCH 26/26] dma-buf: nuke dma_resv_get_excl_unlocked Christian König 2021-09-17 12:35 ` [Intel-gfx] " Christian König 2021-09-17 14:56 ` Daniel Vetter 2021-09-17 14:56 ` [Intel-gfx] " Daniel Vetter 2021-09-17 14:01 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Patchwork 2021-09-17 14:29 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork 2021-09-17 15:43 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork -- strict thread matches above, loose matches on Subject: below -- 2021-09-16 11:30 Deploying new iterator interface for dma-buf Christian König 2021-09-16 11:30 ` [PATCH 01/26] dma-buf: add dma_resv_for_each_fence_unlocked v2 Christian König 2021-09-16 12:15 ` Daniel Vetter
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