drm/i915: Propagate fence errors

Errors spread like wildfire, and must eventually be returned to the
user. They need to be captured and passed along the flow of fences,
infecting each in turn with the existing error, until finally they fall
out of a user visible result.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190817232511.11391-1-chris@chris-wilson.co.uk

1 files changed, 18 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
index 5387aafd3424..dedacafc9442 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -157,8 +157,11 @@ static void __i915_sw_fence_wake_up_all(struct i915_sw_fence *fence,
 		LIST_HEAD(extra);
 
 		do {
-			list_for_each_entry_safe(pos, next, &x->head, entry)
-				pos->func(pos, TASK_NORMAL, 0, &extra);
+			list_for_each_entry_safe(pos, next, &x->head, entry) {
+				pos->func(pos,
+					  TASK_NORMAL, fence->error,
+					  &extra);
+			}
 
 			if (list_empty(&extra))
 				break;
@@ -219,6 +222,8 @@ void __i915_sw_fence_init(struct i915_sw_fence *fence,
 
 	__init_waitqueue_head(&fence->wait, name, key);
 	atomic_set(&fence->pending, 1);
+	fence->error = 0;
+
 	fence->flags = (unsigned long)fn;
 }
 
@@ -230,6 +235,8 @@ void i915_sw_fence_commit(struct i915_sw_fence *fence)
 
 static int i915_sw_fence_wake(wait_queue_entry_t *wq, unsigned mode, int flags, void *key)
 {
+	i915_sw_fence_set_error_once(wq->private, flags);
+
 	list_del(&wq->entry);
 	__i915_sw_fence_complete(wq->private, key);
 
@@ -302,8 +309,10 @@ static int __i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 	debug_fence_assert(fence);
 	might_sleep_if(gfpflags_allow_blocking(gfp));
 
-	if (i915_sw_fence_done(signaler))
+	if (i915_sw_fence_done(signaler)) {
+		i915_sw_fence_set_error_once(fence, signaler->error);
 		return 0;
+	}
 
 	debug_fence_assert(signaler);
 
@@ -319,6 +328,7 @@ static int __i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 				return -ENOMEM;
 
 			i915_sw_fence_wait(signaler);
+			i915_sw_fence_set_error_once(fence, signaler->error);
 			return 0;
 		}
 
@@ -337,7 +347,7 @@ static int __i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 		__add_wait_queue_entry_tail(&signaler->wait, wq);
 		pending = 1;
 	} else {
-		i915_sw_fence_wake(wq, 0, 0, NULL);
+		i915_sw_fence_wake(wq, 0, signaler->error, NULL);
 		pending = 0;
 	}
 	spin_unlock_irqrestore(&signaler->wait.lock, flags);
@@ -372,6 +382,7 @@ static void dma_i915_sw_fence_wake(struct dma_fence *dma,
 {
 	struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
 
+	i915_sw_fence_set_error_once(cb->fence, dma->error);
 	i915_sw_fence_complete(cb->fence);
 	kfree(cb);
 }
@@ -391,6 +402,7 @@ static void timer_i915_sw_fence_wake(struct timer_list *t)
 		  cb->dma->seqno,
 		  i915_sw_fence_debug_hint(fence));
 
+	i915_sw_fence_set_error_once(fence, -ETIMEDOUT);
 	i915_sw_fence_complete(fence);
 }
 
@@ -480,6 +492,7 @@ static void __dma_i915_sw_fence_wake(struct dma_fence *dma,
 {
 	struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
 
+	i915_sw_fence_set_error_once(cb->fence, dma->error);
 	i915_sw_fence_complete(cb->fence);
 }
 
@@ -501,7 +514,7 @@ int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 	if (ret == 0) {
 		ret = 1;
 	} else {
-		i915_sw_fence_complete(fence);
+		__dma_i915_sw_fence_wake(dma, &cb->base);
 		if (ret == -ENOENT) /* fence already signaled */
 			ret = 0;
 	}