drm/syncobj: Add a syncobj_array_find helper

The wait ioctl has a bunch of code to read an syncobj handle array from
userspace and turn it into an array of syncobj pointers.  We're about to
add two new IOCTLs which will need to work with arrays of syncobj
handles so let's make some helpers.
Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_syncobj.c

@@ -798,58 +798,43 @@ static int drm_syncobj_array_wait(struct drm_device *dev,
 	return 0;
 }
 
-int
-drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
-		       struct drm_file *file_private)
+static int drm_syncobj_array_find(struct drm_file *file_private,
+				  void *user_handles, uint32_t count_handles,
+				  struct drm_syncobj ***syncobjs_out)
 {
-	struct drm_syncobj_wait *args = data;
-	uint32_t *handles;
+	uint32_t i, *handles;
 	struct drm_syncobj **syncobjs;
-	int ret = 0;
-	uint32_t i;
-
-	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
-		return -ENODEV;
-
-	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
-			    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
-		return -EINVAL;
-
-	if (args->count_handles == 0)
-		return -EINVAL;
+	int ret;
 
-	/* Get the handles from userspace */
-	handles = kmalloc_array(args->count_handles, sizeof(uint32_t),
-				GFP_KERNEL);
+	handles = kmalloc_array(count_handles, sizeof(*handles), GFP_KERNEL);
 	if (handles == NULL)
 		return -ENOMEM;
 
-	if (copy_from_user(handles,
-			   u64_to_user_ptr(args->handles),
-			   sizeof(uint32_t) * args->count_handles)) {
+	if (copy_from_user(handles, user_handles,
+			   sizeof(uint32_t) * count_handles)) {
 		ret = -EFAULT;
 		goto err_free_handles;
 	}
 
-	syncobjs = kcalloc(args->count_handles,
-			   sizeof(struct drm_syncobj *), GFP_KERNEL);
-	if (!syncobjs) {
+	syncobjs = kmalloc_array(count_handles, sizeof(*syncobjs), GFP_KERNEL);
+	if (syncobjs == NULL) {
 		ret = -ENOMEM;
 		goto err_free_handles;
 	}
 
-	for (i = 0; i < args->count_handles; i++) {
+	for (i = 0; i < count_handles; i++) {
 		syncobjs[i] = drm_syncobj_find(file_private, handles[i]);
 		if (!syncobjs[i]) {
 			ret = -ENOENT;
-			goto err_free_fence_array;
+			goto err_put_syncobjs;
 		}
 	}
 
-	ret = drm_syncobj_array_wait(dev, file_private,
-				     args, syncobjs);
+	kfree(handles);
+	*syncobjs_out = syncobjs;
+	return 0;
 
-err_free_fence_array:
+err_put_syncobjs:
 	while (i-- > 0)
 		drm_syncobj_put(syncobjs[i]);
 	kfree(syncobjs);
@@ -858,3 +843,45 @@ drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
 
 	return ret;
 }
+
+static void drm_syncobj_array_free(struct drm_syncobj **syncobjs,
+				   uint32_t count)
+{
+	uint32_t i;
+	for (i = 0; i < count; i++)
+		drm_syncobj_put(syncobjs[i]);
+	kfree(syncobjs);
+}
+
+int
+drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
+		       struct drm_file *file_private)
+{
+	struct drm_syncobj_wait *args = data;
+	struct drm_syncobj **syncobjs;
+	int ret = 0;
+
+	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
+		return -ENODEV;
+
+	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
+			    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
+		return -EINVAL;
+
+	if (args->count_handles == 0)
+		return -EINVAL;
+
+	ret = drm_syncobj_array_find(file_private,
+				     u64_to_user_ptr(args->handles),
+				     args->count_handles,
+				     &syncobjs);
+	if (ret < 0)
+		return ret;
+
+	ret = drm_syncobj_array_wait(dev, file_private,
+				     args, syncobjs);
+
+	drm_syncobj_array_free(syncobjs, args->count_handles);
+
+	return ret;
+}