On Wed, Nov 26, 2025 at 02:19:10PM +0100, Philipp Stanner wrote:
The dma_fence framework checks at many places whether the signaled flag of a fence is already set. The code can be simplified and made more readable by providing a helper function for that.
Add dma_fence_test_signaled_flag(), which only checks whether a fence is signaled. Use it internally.
Suggested-by: Tvrtko Ursulin tvrtko.ursulin@igalia.com Signed-off-by: Philipp Stanner phasta@kernel.org
This is a nice cleanp: Reviewed-by: Matthew Brost matthew.brost@intel.com
drivers/dma-buf/dma-fence.c | 19 +++++++++---------- include/linux/dma-fence.h | 24 ++++++++++++++++++++++-- 2 files changed, 31 insertions(+), 12 deletions(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 39e6f93dc310..25117a906846 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -372,8 +372,7 @@ int dma_fence_signal_timestamp_locked(struct dma_fence *fence, lockdep_assert_held(fence->lock);
- if (unlikely(test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
&fence->flags)))
- if (unlikely(dma_fence_test_signaled_flag(fence))) return -EINVAL;
/* Stash the cb_list before replacing it with the timestamp */ @@ -545,7 +544,7 @@ void dma_fence_release(struct kref *kref) trace_dma_fence_destroy(fence); if (!list_empty(&fence->cb_list) &&
!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
!dma_fence_test_signaled_flag(fence)) {@@ -602,7 +601,7 @@ static bool __dma_fence_enable_signaling(struct dma_fence *fence) was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags);
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (dma_fence_test_signaled_flag(fence)) return false;
if (!was_set && fence->ops->enable_signaling) { @@ -666,7 +665,7 @@ int dma_fence_add_callback(struct dma_fence *fence, struct dma_fence_cb *cb, if (WARN_ON(!fence || !func)) return -EINVAL;
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
- if (dma_fence_test_signaled_flag(fence)) { INIT_LIST_HEAD(&cb->node); return -ENOENT; }
@@ -783,7 +782,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout) spin_lock_irqsave(fence->lock, flags);
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (dma_fence_test_signaled_flag(fence)) goto out;
if (intr && signal_pending(current)) { @@ -800,7 +799,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout) cb.task = current; list_add(&cb.base.node, &fence->cb_list);
- while (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) && ret > 0) {
- while (!dma_fence_test_signaled_flag(fence) && ret > 0) { if (intr) __set_current_state(TASK_INTERRUPTIBLE); else
@@ -832,7 +831,7 @@ dma_fence_test_signaled_any(struct dma_fence **fences, uint32_t count, for (i = 0; i < count; ++i) { struct dma_fence *fence = fences[i];
if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
if (dma_fence_test_signaled_flag(fence)) { if (idx) *idx = i; return true;@@ -1108,7 +1107,7 @@ const char __rcu *dma_fence_driver_name(struct dma_fence *fence) RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "RCU protection is required for safe access to returned string");
- if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (!dma_fence_test_signaled_flag(fence)) return fence->ops->get_driver_name(fence); else return "detached-driver";
@@ -1140,7 +1139,7 @@ const char __rcu *dma_fence_timeline_name(struct dma_fence *fence) RCU_LOCKDEP_WARN(!rcu_read_lock_held(), "RCU protection is required for safe access to returned string");
- if (!test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (!dma_fence_test_signaled_flag(fence)) return fence->ops->get_timeline_name(fence); else return "signaled-timeline";
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index 64639e104110..19972f5d176f 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -401,6 +401,26 @@ void dma_fence_enable_sw_signaling(struct dma_fence *fence); const char __rcu *dma_fence_driver_name(struct dma_fence *fence); const char __rcu *dma_fence_timeline_name(struct dma_fence *fence); +/*
- dma_fence_test_signaled_flag - Only check whether a fence is signaled yet.
- @fence: the fence to check
- This function just checks whether @fence is signaled, without interacting
- with the fence in any way. The user must, therefore, ensure through other
- means that fences get signaled eventually.
- This function uses test_bit(), which is thread-safe. Naturally, this function
- should be used opportunistically; a fence could get signaled at any moment
- after the check is done.
- Return: true if signaled, false otherwise.
- */
+static inline bool +dma_fence_test_signaled_flag(struct dma_fence *fence) +{
- return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags);
+}
/**
- dma_fence_is_signaled_locked - Return an indication if the fence
is signaled yet.@@ -418,7 +438,7 @@ const char __rcu *dma_fence_timeline_name(struct dma_fence *fence); static inline bool dma_fence_is_signaled_locked(struct dma_fence *fence) {
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (dma_fence_test_signaled_flag(fence)) return true;
if (fence->ops->signaled && fence->ops->signaled(fence)) { @@ -448,7 +468,7 @@ dma_fence_is_signaled_locked(struct dma_fence *fence) static inline bool dma_fence_is_signaled(struct dma_fence *fence) {
- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
- if (dma_fence_test_signaled_flag(fence)) return true;
if (fence->ops->signaled && fence->ops->signaled(fence)) { -- 2.49.0