dma_fence_wait_any_timeout only relies on two things to work correctly:
1) The callback list to get called upon fence signal 2) The SIGNALED flag to be set upon fence signal
The first if these is part of the core dma-fence API. The second is only mostly part of the core dma-fence API with the one issue that the flag may not be set and dma_fence_is_signaled may never return true if fence->ops->enable_signaling() has not been called. It's easy enough to work around that by always using dma_fence_is_signaled instead of manually checking the bit and falling through to a zero-timeout wait if none of the fences report that they are signaled.
v2: - Use dma_fence_is_signaled in test_signaled_any - Fall through to a zero-timeout wait
Cc: Christian König christian.koenig@amd.com Signed-off-by: Jason Ekstrand jason@jlekstrand.net --- drivers/dma-buf/dma-fence.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 9a30279..0cac367 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -437,8 +437,7 @@ dma_fence_test_signaled_any(struct dma_fence **fences, uint32_t count, int i;
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_is_signaled(fences[i])) { if (idx) *idx = i; return true; @@ -484,7 +483,13 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count, return 1; }
- return 0; + /* There's a very annoying laxness in the dma_fence API + * here, in that backends are not required to automatically + * report when a fence is signaled prior to + * fence->ops->enable_signaling() being called. So here if + * we fail to match signaled_count, we need to fallthough + * and try a 0 timeout wait! + */ }
cb = kcalloc(count, sizeof(struct default_wait_cb), GFP_KERNEL); @@ -496,11 +501,6 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count, for (i = 0; i < count; ++i) { struct dma_fence *fence = fences[i];
- if (fence->ops->wait != dma_fence_default_wait) { - ret = -EINVAL; - goto fence_rm_cb; - } - cb[i].task = current; if (dma_fence_add_callback(fence, &cb[i].base, dma_fence_default_wait_cb)) { @@ -511,7 +511,7 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count, } }
- while (ret > 0) { + do { if (intr) set_current_state(TASK_INTERRUPTIBLE); else @@ -524,7 +524,7 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
if (ret > 0 && intr && signal_pending(current)) ret = -ERESTARTSYS; - } + } while (ret > 0);
__set_current_state(TASK_RUNNING);