drm/fb-helper: Push locking in fb_is_bound

That function only needs to take the individual crtc locks, not all
the kms locks. Push down the locking and then minimize it.

Cc: John Stultz <john.stultz@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170704151833.17304-5-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 30188ec809b5082f45ee0d436d120897a664ea1d..08a5e0d23a4288a84cc0f404ca7d5d84ebd546f6 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -543,10 +543,12 @@ static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
                return false;
 
        drm_for_each_crtc(crtc, dev) {
+               drm_modeset_lock(&crtc->mutex, NULL);
                if (crtc->primary->fb)
                        crtcs_bound++;
                if (crtc->primary->fb == fb_helper->fb)
                        bound++;
+               drm_modeset_unlock(&crtc->mutex);
        }
 
        if (bound < crtcs_bound)
@@ -621,13 +623,12 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
         * For each CRTC in this fb, turn the connectors on/off.
         */
        mutex_lock(&fb_helper->lock);
-       drm_modeset_lock_all(dev);
        if (!drm_fb_helper_is_bound(fb_helper)) {
-               drm_modeset_unlock_all(dev);
                mutex_unlock(&fb_helper->lock);
                return;
        }
 
+       drm_modeset_lock_all(dev);
        for (i = 0; i < fb_helper->crtc_count; i++) {
                crtc = fb_helper->crtc_info[i].mode_set.crtc;
 
@@ -1263,13 +1264,12 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
                return -EBUSY;
 
        mutex_lock(&fb_helper->lock);
-       drm_modeset_lock_all(dev);
        if (!drm_fb_helper_is_bound(fb_helper)) {
-               drm_modeset_unlock_all(dev);
                mutex_unlock(&fb_helper->lock);
                return -EBUSY;
        }
 
+       drm_modeset_lock_all(dev);
        for (i = 0; i < fb_helper->crtc_count; i++) {
                crtc = fb_helper->crtc_info[i].mode_set.crtc;
                crtc_funcs = crtc->helper_private;
@@ -1323,12 +1323,12 @@ int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
        int ret = 0;
 
        mutex_lock(&fb_helper->lock);
-       mutex_lock(&dev->mode_config.mutex);
        if (!drm_fb_helper_is_bound(fb_helper)) {
                ret = -EBUSY;
                goto unlock;
        }
 
+       mutex_lock(&dev->mode_config.mutex);
        switch (cmd) {
        case FBIO_WAITFORVSYNC:
                /*
@@ -1600,13 +1600,12 @@ int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
                return -EBUSY;
 
        mutex_lock(&fb_helper->lock);
-       drm_modeset_lock_all(dev);
        if (!drm_fb_helper_is_bound(fb_helper)) {
-               drm_modeset_unlock_all(dev);
                mutex_unlock(&fb_helper->lock);
                return -EBUSY;
        }
 
+       drm_modeset_lock_all(dev);
        if (drm_drv_uses_atomic_modeset(dev))
                ret = pan_display_atomic(var, info);
        else
@@ -2467,16 +2466,15 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
                return 0;
 
        mutex_lock(&fb_helper->lock);
-       mutex_lock(&dev->mode_config.mutex);
-
        if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) {
                fb_helper->delayed_hotplug = true;
-               mutex_unlock(&dev->mode_config.mutex);
-               goto unlock;
+               mutex_unlock(&fb_helper->lock);
+               return err;
        }
 
        DRM_DEBUG_KMS("\n");
 
+       mutex_lock(&dev->mode_config.mutex);
        drm_setup_crtcs(fb_helper, fb_helper->fb->width, fb_helper->fb->height);
 
        mutex_unlock(&dev->mode_config.mutex);
@@ -2485,10 +2483,6 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
        drm_fb_helper_set_par(fb_helper->fbdev);
 
        return 0;
-
-unlock:
-       mutex_unlock(&fb_helper->lock);
-       return err;
 }
 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);