[Intel-gfx] [RFC PATCH 2/3] drm/i915: Change locking for struct_mutex.

[Maarten Lankhorst]

Only acquire the struct_mutex once, and interruptibly.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0730c71aa279..f7e27b539c03 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13004,8 +13004,13 @@ static int intel_atomic_prepare_commit(struct drm_device *dev,
 			return ret;
 	}
 
+	ret = i915_mutex_lock_interruptible(dev);
+	if (ret)
+		return ret;
+
 	ret = drm_atomic_helper_prepare_planes(dev, state);
 
+	mutex_unlock(&dev->struct_mutex);
 	return ret;
 }
 
@@ -13106,7 +13111,10 @@ static int intel_atomic_commit(struct drm_device *dev,
 	/* FIXME: add subpixel order */
 
 	drm_atomic_helper_wait_for_vblanks(dev, state);
+
+	mutex_lock(&dev->struct_mutex);
 	drm_atomic_helper_cleanup_planes(dev, state);
+	mutex_unlock(&dev->struct_mutex);
 
 	if (any_ms)
 		intel_modeset_check_state(dev, state);
@@ -13293,10 +13301,6 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	if (!obj && !old_obj)
 		return 0;
 
-	ret = i915_mutex_lock_interruptible(dev);
-	if (ret)
-		return ret;
-
 	if (old_obj) {
 		struct drm_crtc_state *crtc_state =
 			drm_atomic_get_existing_crtc_state(new_state->state, plane->state->crtc);
@@ -13317,7 +13321,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 
 		/* Swallow -EIO errors to allow updates during hw lockup. */
 		if (ret && ret != -EIO)
-			goto out;
+			return ret;
 	}
 
 	if (!obj) {
@@ -13335,9 +13339,6 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	if (ret == 0)
 		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);
 
-out:
-	mutex_unlock(&dev->struct_mutex);
-
 	return ret;
 }
 
@@ -13360,7 +13361,6 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
 	if (!obj && !old_obj)
 		return;
 
-	mutex_lock(&dev->struct_mutex);
 	if (old_obj && (plane->type != DRM_PLANE_TYPE_CURSOR ||
 	    !INTEL_INFO(dev)->cursor_needs_physical))
 		intel_unpin_fb_obj(old_state->fb, old_state);
@@ -13369,7 +13369,6 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
 	if ((old_obj && (old_obj->frontbuffer_bits & intel_plane->frontbuffer_bit)) ||
 	    (obj && !(obj->frontbuffer_bits & intel_plane->frontbuffer_bit)))
 		i915_gem_track_fb(old_obj, obj, intel_plane->frontbuffer_bit);
-	mutex_unlock(&dev->struct_mutex);
 }
 
 int
-- 
2.1.0