drm/vmwgfx: Kill some lockdep warnings

Some global KMS state that is elsewhere protected by the mode_config
mutex here needs to be protected with a local mutex. Remove corresponding
lockdep checks and introduce a new driver-private global_kms_state_mutex,
and make sure its locking order is *after* the crtc locks in order to
avoid having to release those when the new mutex is taken.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Cc: <stable@vger.kernel.org> # 4.6

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 9555e20..e80497e 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -628,6 +628,7 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
        mutex_init(&dev_priv->cmdbuf_mutex);
        mutex_init(&dev_priv->release_mutex);
        mutex_init(&dev_priv->binding_mutex);
+       mutex_init(&dev_priv->global_kms_state_mutex);
        rwlock_init(&dev_priv->resource_lock);
        ttm_lock_init(&dev_priv->reservation_sem);
        spin_lock_init(&dev_priv->hw_lock);

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 019a6ca..6db358a 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -412,6 +412,7 @@ struct vmw_private {
        struct drm_property *implicit_placement_property;
        unsigned num_implicit;
        struct vmw_framebuffer *implicit_fb;
+       struct mutex global_kms_state_mutex;
 
        /*
         * Context and surface management.

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index fc20d45..55231cc 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -2143,13 +2143,13 @@ int vmw_kms_fbdev_init_data(struct vmw_private *dev_priv,
 void vmw_kms_del_active(struct vmw_private *dev_priv,
                        struct vmw_display_unit *du)
 {
-       lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
+       mutex_lock(&dev_priv->global_kms_state_mutex);
        if (du->active_implicit) {
                if (--(dev_priv->num_implicit) == 0)
                        dev_priv->implicit_fb = NULL;
                du->active_implicit = false;
        }
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 }
 
 /**
@@ -2165,8 +2165,7 @@ void vmw_kms_add_active(struct vmw_private *dev_priv,
                        struct vmw_display_unit *du,
                        struct vmw_framebuffer *vfb)
 {
-       lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
+       mutex_lock(&dev_priv->global_kms_state_mutex);
        WARN_ON_ONCE(!dev_priv->num_implicit && dev_priv->implicit_fb);
 
        if (!du->active_implicit && du->is_implicit) {
@@ -2174,6 +2173,7 @@ void vmw_kms_add_active(struct vmw_private *dev_priv,
                du->active_implicit = true;
                dev_priv->num_implicit++;
        }
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 }
 
 /**
@@ -2190,16 +2190,13 @@ bool vmw_kms_crtc_flippable(struct vmw_private *dev_priv,
                            struct drm_crtc *crtc)
 {
        struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
+       bool ret;
 
-       lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
-
-       if (!du->is_implicit)
-               return true;
-
-       if (dev_priv->num_implicit != 1)
-               return false;
+       mutex_lock(&dev_priv->global_kms_state_mutex);
+       ret = !du->is_implicit || dev_priv->num_implicit == 1;
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 
-       return true;
+       return ret;
 }
 
 /**
@@ -2214,16 +2211,18 @@ void vmw_kms_update_implicit_fb(struct vmw_private *dev_priv,
        struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
        struct vmw_framebuffer *vfb;
 
-       lockdep_assert_held_once(&dev_priv->dev->mode_config.mutex);
+       mutex_lock(&dev_priv->global_kms_state_mutex);
 
        if (!du->is_implicit)
-               return;
+               goto out_unlock;
 
        vfb = vmw_framebuffer_to_vfb(crtc->primary->fb);
        WARN_ON_ONCE(dev_priv->num_implicit != 1 &&
                     dev_priv->implicit_fb != vfb);
 
        dev_priv->implicit_fb = vfb;
+out_unlock:
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 }
 
 /**

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
index 0ea22fd..b74eae2 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -285,14 +285,17 @@ static int vmw_sou_crtc_set_config(struct drm_mode_set *set)
        }
 
        /* Only one active implicit frame-buffer at a time. */
+       mutex_lock(&dev_priv->global_kms_state_mutex);
        if (sou->base.is_implicit &&
            dev_priv->implicit_fb && vfb &&
            !(dev_priv->num_implicit == 1 &&
              sou->base.active_implicit) &&
            dev_priv->implicit_fb != vfb) {
+               mutex_unlock(&dev_priv->global_kms_state_mutex);
                DRM_ERROR("Multiple implicit framebuffers not supported.\n");
                return -EINVAL;
        }
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 
        /* since they always map one to one these are safe */
        connector = &sou->base.connector;

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index b949102..9ca818f 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -553,12 +553,15 @@ static int vmw_stdu_crtc_set_config(struct drm_mode_set *set)
        }
 
        /* Only one active implicit frame-buffer at a time. */
+       mutex_lock(&dev_priv->global_kms_state_mutex);
        if (!turning_off && stdu->base.is_implicit && dev_priv->implicit_fb &&
            !(dev_priv->num_implicit == 1 && stdu->base.active_implicit)
            && dev_priv->implicit_fb != vfb) {
+               mutex_unlock(&dev_priv->global_kms_state_mutex);
                DRM_ERROR("Multiple implicit framebuffers not supported.\n");
                return -EINVAL;
        }
+       mutex_unlock(&dev_priv->global_kms_state_mutex);
 
        /* Since they always map one to one these are safe */
        connector = &stdu->base.connector;