[PATCH 2/2] drm/kms: Fix missing locking in some fb helpers.

[Francisco Jerez]

Signed-off-by: Francisco Jerez <currojerez at riseup.net>
---
 drivers/gpu/drm/drm_fb_helper.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 6a5e403..4d608b7 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1449,6 +1449,8 @@ bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
 	struct drm_device *dev = fb_helper->dev;
 	int count = 0;
 
+	mutex_lock(&dev->mode_config.mutex);
+
 	/* disable all the possible outputs/crtcs before entering KMS mode */
 	drm_helper_disable_unused_functions(fb_helper->dev);
 
@@ -1465,19 +1467,23 @@ bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
 	}
 	drm_setup_crtcs(fb_helper);
 
+	mutex_unlock(&dev->mode_config.mutex);
+
 	return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
 }
 EXPORT_SYMBOL(drm_fb_helper_initial_config);
 
 bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
 {
+	struct drm_device *dev = fb_helper->dev;
 	int count = 0;
 	u32 max_width, max_height, bpp_sel;
 	bool bound = false, crtcs_bound = false;
 	struct drm_crtc *crtc;
 
+	mutex_lock(&dev->mode_config.mutex);
 	if (!fb_helper->fb)
-		return false;
+		goto fail;
 
 	list_for_each_entry(crtc, &fb_helper->dev->mode_config.crtc_list, head) {
 		if (crtc->fb)
@@ -1488,7 +1494,7 @@ bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
 
 	if (!bound && crtcs_bound) {
 		fb_helper->delayed_hotplug = true;
-		return false;
+		goto fail;
 	}
 	DRM_DEBUG_KMS("\n");
 
@@ -1500,7 +1506,11 @@ bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
 						    max_height);
 	drm_setup_crtcs(fb_helper);
 
+	mutex_unlock(&dev->mode_config.mutex);
 	return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
+fail:
+	mutex_unlock(&dev->mode_config.mutex);
+	return false;
 }
 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
 
-- 
1.6.4.4