On 12/1/25 11:50, 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 <[email protected]> > Signed-off-by: Philipp Stanner <[email protected]>
Reviewed-by: Christian König <[email protected]> > --- > drivers/dma-buf/dma-fence.c | 16 ++++++++-------- > include/linux/dma-fence.h | 24 ++++++++++++++++++++++-- > 2 files changed, 30 insertions(+), 10 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c > index 39e6f93dc310..96d72ffc0750 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -545,7 +545,7 @@ 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)) { > const char __rcu *timeline; > const char __rcu *driver; > unsigned long flags; > @@ -602,7 +602,7 @@ 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 +666,7 @@ 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 +783,7 @@ 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 +800,7 @@ 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 +832,7 @@ 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 +1108,7 @@ 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 +1140,7 @@ 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)) {
