When one of the array of fences is signaled, propagate its errors to the
parent fence-array (keeping the first error to be raised).
v2: Opencode cmpxchg_local to avoid compiler freakout.
v3: Be careful not to flag an error if we race against signal-on-any
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
---
drivers/dma-buf/dma-fence-array.c | 25 +++++++++++++++++++++++++
include/linux/dma-fence-array.h | 2 ++
2 files changed, 27 insertions(+)
diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
index 12c6f64c0bc2..e806c5fe9ec9 100644
--- a/drivers/dma-buf/dma-fence-array.c
+++ b/drivers/dma-buf/dma-fence-array.c
@@ -23,10 +23,19 @@ static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
return "unbound";
}
+static void dma_fence_array_set_error_once(struct dma_fence_array *array,
+ int error)
+{
+ if (!array->base.error && error)
+ dma_fence_set_error(&array->base, error);
+}
+
static void irq_dma_fence_array_work(struct irq_work *wrk)
{
struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
+ dma_fence_array_set_error_once(array, READ_ONCE(array->pending_error));
+
dma_fence_signal(&array->base);
dma_fence_put(&array->base);
}
@@ -38,6 +47,19 @@ static void dma_fence_array_cb_func(struct dma_fence *f,
container_of(cb, struct dma_fence_array_cb, cb);
struct dma_fence_array *array = array_cb->array;
+ /*
+ * Propagate the first error reported by any of our fences, but only
+ * before we ourselves are signaled.
+ *
+ * Note that this may race with multiple fences completing
+ * simultaneously in error, but only one error will be kept, not
+ * necessarily the first. So long as we propagate an error if any
+ * fences were in error before we are signaled we should be telling
+ * an acceptable truth.
+ */
+ if (f->error && !array->pending_error)
+ WRITE_ONCE(array->pending_error, f->error);
+
if (atomic_dec_and_test(&array->num_pending))
irq_work_queue(&array->work);
else
@@ -63,6 +85,8 @@ static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
dma_fence_get(&array->base);
if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
dma_fence_array_cb_func)) {
+ dma_fence_array_set_error_once(array,
+ array->fences[i]->error);
dma_fence_put(&array->base);
if (atomic_dec_and_test(&array->num_pending))
return false;
@@ -141,6 +165,7 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
array->num_fences = num_fences;
atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
array->fences = fences;
+ array->pending_error = 0;
return array;
}
diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
index 303dd712220f..faaf70c524ae 100644
--- a/include/linux/dma-fence-array.h
+++ b/include/linux/dma-fence-array.h
@@ -42,6 +42,8 @@ struct dma_fence_array {
atomic_t num_pending;
struct dma_fence **fences;
+ int pending_error;
+
struct irq_work work;
};
--
2.23.0.rc1
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