From: Thierry Reding treding@nvidia.com
Introduce a new top-level lock for the FB helper code. This will allow better locking granularity and avoid the need to abuse modeset locking for this purpose instead.
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/drm_fb_helper.c | 27 ++++++++++++++++++++++++++- include/drm/drm_fb_helper.h | 5 +++++ 2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 252c7557bdb5..f7722bcb0064 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -105,6 +105,7 @@ static int __drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, if (!drm_fbdev_emulation) return 0;
+ WARN_ON(!mutex_is_locked(&fb_helper->lock)); WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
count = fb_helper->connector_count + 1; @@ -127,6 +128,7 @@ static int __drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, drm_connector_reference(connector); conn->connector = connector; fb_helper->connector_info[fb_helper->connector_count++] = conn; + return 0; }
@@ -135,11 +137,13 @@ int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, { int err;
+ mutex_lock(&fb_helper->lock); mutex_lock(&fb_helper->dev->mode_config.mutex);
err = __drm_fb_helper_add_one_connector(fb_helper, connector);
mutex_unlock(&fb_helper->dev->mode_config.mutex); + mutex_unlock(&fb_helper->lock);
return err; } @@ -168,6 +172,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) if (!drm_fbdev_emulation) return 0;
+ mutex_lock(&fb_helper->lock); mutex_lock(&dev->mode_config.mutex);
drm_for_each_connector(connector, dev) { @@ -184,6 +189,7 @@ int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper) }
mutex_unlock(&dev->mode_config.mutex); + mutex_unlock(&fb_helper->lock);
return ret; } @@ -198,6 +204,7 @@ static int __drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper, if (!drm_fbdev_emulation) return 0;
+ WARN_ON(!mutex_is_locked(&fb_helper->lock)); WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
for (i = 0; i < fb_helper->connector_count; i++) { @@ -225,11 +232,13 @@ int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper, { int err;
+ mutex_lock(&fb_helper->lock); mutex_lock(&fb_helper->dev->mode_config.mutex);
err = __drm_fb_helper_remove_one_connector(fb_helper, connector);
mutex_unlock(&fb_helper->dev->mode_config.mutex); + mutex_unlock(&fb_helper->lock);
return err; } @@ -478,16 +487,21 @@ int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper) if (!drm_fbdev_emulation) return -ENODEV;
+ mutex_lock(&fb_helper->lock); drm_modeset_lock_all(dev); + ret = restore_fbdev_mode(fb_helper);
do_delayed = fb_helper->delayed_hotplug; if (do_delayed) fb_helper->delayed_hotplug = false; + drm_modeset_unlock_all(dev); + mutex_unlock(&fb_helper->lock);
if (do_delayed) drm_fb_helper_hotplug_event(fb_helper); + return ret; } EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked); @@ -688,6 +702,7 @@ void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper, spin_lock_init(&helper->dirty_lock); INIT_WORK(&helper->dirty_work, drm_fb_helper_dirty_work); helper->dirty_clip.x1 = helper->dirty_clip.y1 = ~0; + mutex_init(&helper->lock); helper->funcs = funcs; helper->dev = dev; } @@ -853,6 +868,7 @@ void drm_fb_helper_fini(struct drm_fb_helper *fb_helper) unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op); }
+ mutex_destroy(&fb_helper->lock); drm_fb_helper_crtc_free(fb_helper);
} @@ -2273,16 +2289,20 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper) { struct drm_device *dev = fb_helper->dev; u32 max_width, max_height; + int err = 0;
if (!drm_fbdev_emulation) return 0;
+ mutex_lock(&fb_helper->lock); mutex_lock(&fb_helper->dev->mode_config.mutex); + if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) { fb_helper->delayed_hotplug = true; mutex_unlock(&fb_helper->dev->mode_config.mutex); - return 0; + goto unlock; } + DRM_DEBUG_KMS("\n");
max_width = fb_helper->fb->width; @@ -2290,6 +2310,7 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
drm_fb_helper_probe_connector_modes(fb_helper, max_width, max_height); mutex_unlock(&fb_helper->dev->mode_config.mutex); + mutex_unlock(&fb_helper->lock);
drm_modeset_lock_all(dev); drm_setup_crtcs(fb_helper); @@ -2297,6 +2318,10 @@ 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);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index 5b4aa35026a3..7739be08ebca 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -198,6 +198,11 @@ struct drm_fb_helper { struct work_struct dirty_work;
/** + * Top-level FB helper lock. + */ + struct mutex lock; + + /** * @kernel_fb_list: * * Entry on the global kernel_fb_helper_list, used for kgdb entry/exit.