Re: [PATCH v5] dma-fence: Propagate errors to dma-fence-array container

Am 11.08.19 um 18:25 schrieb Chris Wilson:

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. v4: Same applies to installing the signal cb. v5: Use cmpxchg to only set the error once before using a nifty idea by Christian to avoid changing the status after emitting the signal.

Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Gustavo Padovan gustavo@padovan.org Cc: Christian König christian.koenig@amd.com

Reviewed-by: Christian König christian.koenig@amd.com

---

drivers/dma-buf/dma-fence-array.c | 32 ++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c index 12c6f64c0bc2..d3fbd950be94 100644 --- a/drivers/dma-buf/dma-fence-array.c +++ b/drivers/dma-buf/dma-fence-array.c @@ -13,6 +13,8 @@ #include <linux/slab.h> #include <linux/dma-fence-array.h>

+#define PENDING_ERROR 1

• static const char *dma_fence_array_get_driver_name(struct dma_fence *fence) { return "dma_fence_array";

@@ -23,10 +25,29 @@ static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence) return "unbound"; }

+static void dma_fence_array_set_pending_error(struct dma_fence_array *array,

• 			      int error)
  

+{

• /*

• * Propagate the first error reported by any of our fences, but only
  

• * before we ourselves are signaled.
  

• */
  

• if (error)

• cmpxchg(&array->base.error, PENDING_ERROR, error);
  

+}

+static void dma_fence_array_clear_pending_error(struct dma_fence_array *array) +{

• /* Clear the error flag if not actually set. */
• cmpxchg(&array->base.error, PENDING_ERROR, 0);

+}

• 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_clear_pending_error(array);

• dma_fence_signal(&array->base); dma_fence_put(&array->base); }

@@ -38,6 +59,8 @@ 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;

• dma_fence_array_set_pending_error(array, f->error);
• if (atomic_dec_and_test(&array->num_pending)) irq_work_queue(&array->work); else

@@ -63,9 +86,14 @@ 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)) {

• 	int error = array->fences[i]->error;
  

• 	dma_fence_array_set_pending_error(array, error);
  dma_fence_put(&array->base);
  

• 	if (atomic_dec_and_test(&array->num_pending))
  

• 	if (atomic_dec_and_test(&array->num_pending)) {
  

• 		dma_fence_array_clear_pending_error(array);
  	return false;
  

• 	}
  

  } }

@@ -142,6 +170,8 @@ struct dma_fence_array *dma_fence_array_create(int num_fences, atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); array->fences = fences;

• array->base.error = PENDING_ERROR;
• return array; } EXPORT_SYMBOL(dma_fence_array_create);