drm: Remove drm_modeset_(un)lock_crtc

The last user, the cursor ioctl, can just open-code this too. We
simply have to move the acquire ctx dance from the universal function
up into the top-level ioctl handler.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170403083304.9083-3-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_crtc_internal.h

@@ -61,9 +61,6 @@ int drm_mode_getresources(struct drm_device *dev,
 			  void *data, struct drm_file *file_priv);
 
 
-/* drm_modeset_lock.c */
-void drm_modeset_lock_crtc(struct drm_crtc *crtc,
-			   struct drm_plane *plane);
 /* drm_dumb_buffers.c */
 /* IOCTLs */
 int drm_mode_create_dumb_ioctl(struct drm_device *dev,

drivers/gpu/drm/drm_modeset_lock.c

@@ -148,51 +148,6 @@ void drm_modeset_unlock_all(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_modeset_unlock_all);
 
-void drm_modeset_lock_crtc(struct drm_crtc *crtc,
-			   struct drm_plane *plane)
-{
-	struct drm_modeset_acquire_ctx *ctx;
-	int ret;
-
-	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
-	if (WARN_ON(!ctx))
-		return;
-
-	drm_modeset_acquire_init(ctx, 0);
-
-retry:
-	ret = drm_modeset_lock(&crtc->mutex, ctx);
-	if (ret)
-		goto fail;
-
-	if (plane) {
-		ret = drm_modeset_lock(&plane->mutex, ctx);
-		if (ret)
-			goto fail;
-
-		if (plane->crtc) {
-			ret = drm_modeset_lock(&plane->crtc->mutex, ctx);
-			if (ret)
-				goto fail;
-		}
-	}
-
-	WARN_ON(crtc->acquire_ctx);
-
-	/* now we hold the locks, so now that it is safe, stash the
-	 * ctx for drm_modeset_unlock_crtc():
-	 */
-	crtc->acquire_ctx = ctx;
-
-	return;
-
-fail:
-	if (ret == -EDEADLK) {
-		drm_modeset_backoff(ctx);
-		goto retry;
-	}
-}
-
 /**
  * drm_modeset_legacy_acquire_ctx - find acquire ctx for legacy ioctls
  * @crtc: drm crtc
@@ -214,28 +169,6 @@ drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc)
 }
 EXPORT_SYMBOL(drm_modeset_legacy_acquire_ctx);
 
-/**
- * drm_modeset_unlock_crtc - drop crtc lock
- * @crtc: drm crtc
- *
- * This drops the crtc lock acquire with drm_modeset_lock_crtc() and all other
- * locks acquired through the hidden context.
- */
-void drm_modeset_unlock_crtc(struct drm_crtc *crtc)
-{
-	struct drm_modeset_acquire_ctx *ctx = crtc->acquire_ctx;
-
-	if (WARN_ON(!ctx))
-		return;
-
-	crtc->acquire_ctx = NULL;
-	drm_modeset_drop_locks(ctx);
-	drm_modeset_acquire_fini(ctx);
-
-	kfree(ctx);
-}
-EXPORT_SYMBOL(drm_modeset_unlock_crtc);
-
 /**
  * drm_warn_on_modeset_not_all_locked - check that all modeset locks are locked
  * @dev: device

drivers/gpu/drm/drm_plane.c

@@ -620,7 +620,8 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
 
 static int drm_mode_cursor_universal(struct drm_crtc *crtc,
 				     struct drm_mode_cursor2 *req,
-				     struct drm_file *file_priv)
+				     struct drm_file *file_priv,
+				     struct drm_modeset_acquire_ctx *ctx)
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_framebuffer *fb = NULL;
@@ -634,21 +635,11 @@ static int drm_mode_cursor_universal(struct drm_crtc *crtc,
 	int32_t crtc_x, crtc_y;
 	uint32_t crtc_w = 0, crtc_h = 0;
 	uint32_t src_w = 0, src_h = 0;
-	struct drm_modeset_acquire_ctx ctx;
 	int ret = 0;
 
 	BUG_ON(!crtc->cursor);
 	WARN_ON(crtc->cursor->crtc != crtc && crtc->cursor->crtc != NULL);
 
-	drm_modeset_acquire_init(&ctx, 0);
-retry:
-	ret = drm_modeset_lock(&crtc->mutex, &ctx);
-	if (ret)
-		goto fail;
-	ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
-	if (ret)
-		goto fail;
-
 	/*
 	 * Obtain fb we'll be using (either new or existing) and take an extra
 	 * reference to it if fb != null.  setplane will take care of dropping
@@ -693,7 +684,7 @@ retry:
 	 */
 	ret = __setplane_internal(crtc->cursor, crtc, fb,
 				crtc_x, crtc_y, crtc_w, crtc_h,
-				0, 0, src_w, src_h, &ctx);
+				0, 0, src_w, src_h, ctx);
 
 	/* Update successful; save new cursor position, if necessary */
 	if (ret == 0 && req->flags & DRM_MODE_CURSOR_MOVE) {
@@ -701,15 +692,6 @@ retry:
 		crtc->cursor_y = req->y;
 	}
 
-fail:
-	if (ret == -EDEADLK) {
-		drm_modeset_backoff(&ctx);
-		goto retry;
-	}
-
-	drm_modeset_drop_locks(&ctx);
-	drm_modeset_acquire_fini(&ctx);
-
 	return ret;
 }
 
@@ -718,6 +700,7 @@ static int drm_mode_cursor_common(struct drm_device *dev,
 				  struct drm_file *file_priv)
 {
 	struct drm_crtc *crtc;
+	struct drm_modeset_acquire_ctx ctx;
 	int ret = 0;
 
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
@@ -732,14 +715,24 @@ static int drm_mode_cursor_common(struct drm_device *dev,
 		return -ENOENT;
 	}
 
+	drm_modeset_acquire_init(&ctx, 0);
+retry:
+	ret = drm_modeset_lock(&crtc->mutex, &ctx);
+	if (ret)
+		goto out;
+	ret = drm_modeset_lock(&crtc->cursor->mutex, &ctx);
+	if (ret)
+		goto out;
+
 	/*
 	 * If this crtc has a universal cursor plane, call that plane's update
 	 * handler rather than using legacy cursor handlers.
 	 */
-	if (crtc->cursor)
+	if (crtc->cursor) {
-		return drm_mode_cursor_universal(crtc, req, file_priv);
+		ret = drm_mode_cursor_universal(crtc, req, file_priv, &ctx);
+		goto out;
+	}
 
-	drm_modeset_lock_crtc(crtc, crtc->cursor);
 	if (req->flags & DRM_MODE_CURSOR_BO) {
 		if (!crtc->funcs->cursor_set && !crtc->funcs->cursor_set2) {
 			ret = -ENXIO;
@@ -763,7 +756,13 @@ static int drm_mode_cursor_common(struct drm_device *dev,
 		}
 	}
 out:
-	drm_modeset_unlock_crtc(crtc);
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry;
+	}
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
 
 	return ret;
 

include/drm/drm_modeset_lock.h

@@ -121,7 +121,6 @@ struct drm_plane;
 
 void drm_modeset_lock_all(struct drm_device *dev);
 void drm_modeset_unlock_all(struct drm_device *dev);
-void drm_modeset_unlock_crtc(struct drm_crtc *crtc);
 void drm_warn_on_modeset_not_all_locked(struct drm_device *dev);
 struct drm_modeset_acquire_ctx *
 drm_modeset_legacy_acquire_ctx(struct drm_crtc *crtc);