drm/i915: use new iterator in i915_gem_object_wait_reservation

Simplifying the code a bit.
Signed-off-by: Christian König <christian.koenig@amd.com>
[mlankhorst: Handle timeout = 0 correctly, use new i915_request_wait_timeout.]
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116102431.198905-7-christian.koenig@amd.com

drivers/gpu/drm/i915/gem/i915_gem_wait.c

@@ -25,7 +25,7 @@ i915_gem_object_wait_fence(struct dma_fence *fence,
 		return timeout;
 
 	if (dma_fence_is_i915(fence))
-		return i915_request_wait(to_request(fence), flags, timeout);
+		return i915_request_wait_timeout(to_request(fence), flags, timeout);
 
 	return dma_fence_wait_timeout(fence,
 				      flags & I915_WAIT_INTERRUPTIBLE,
@@ -37,58 +37,29 @@ i915_gem_object_wait_reservation(struct dma_resv *resv,
 				 unsigned int flags,
 				 long timeout)
 {
-	struct dma_fence *excl;
-	bool prune_fences = false;
-
-	if (flags & I915_WAIT_ALL) {
-		struct dma_fence **shared;
-		unsigned int count, i;
-		int ret;
-
-		ret = dma_resv_get_fences(resv, &excl, &count, &shared);
-		if (ret)
-			return ret;
-
-		for (i = 0; i < count; i++) {
-			timeout = i915_gem_object_wait_fence(shared[i],
-							     flags, timeout);
-			if (timeout < 0)
-				break;
-
-			dma_fence_put(shared[i]);
-		}
+	struct dma_resv_iter cursor;
+	struct dma_fence *fence;
+	long ret = timeout ?: 1;
 
-		for (; i < count; i++)
-			dma_fence_put(shared[i]);
-		kfree(shared);
+	dma_resv_iter_begin(&cursor, resv, flags & I915_WAIT_ALL);
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		ret = i915_gem_object_wait_fence(fence, flags, timeout);
+		if (ret <= 0)
+			break;
 
-		/*
-		 * If both shared fences and an exclusive fence exist,
-		 * then by construction the shared fences must be later
-		 * than the exclusive fence. If we successfully wait for
-		 * all the shared fences, we know that the exclusive fence
-		 * must all be signaled. If all the shared fences are
-		 * signaled, we can prune the array and recover the
-		 * floating references on the fences/requests.
-		 */
-		prune_fences = count && timeout >= 0;
-	} else {
-		excl = dma_resv_get_excl_unlocked(resv);
+		if (timeout)
+			timeout = ret;
 	}
-
-	if (excl && timeout >= 0)
-		timeout = i915_gem_object_wait_fence(excl, flags, timeout);
-
-	dma_fence_put(excl);
+	dma_resv_iter_end(&cursor);
 
 	/*
 	 * Opportunistically prune the fences iff we know they have *all* been
 	 * signaled.
 	 */
-	if (prune_fences)
+	if (timeout > 0)
 		dma_resv_prune(resv);
 
-	return timeout;
+	return ret;
 }
 
 static void fence_set_priority(struct dma_fence *fence,
@@ -177,7 +148,11 @@ i915_gem_object_wait(struct drm_i915_gem_object *obj,
 
 	timeout = i915_gem_object_wait_reservation(obj->base.resv,
 						   flags, timeout);
-	return timeout < 0 ? timeout : 0;
+
+	if (timeout < 0)
+		return timeout;
+
+	return !timeout ? -ETIME : 0;
 }
 
 static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)