Atm we still need to unconditionally take the modeset locks in the rmfb paths. But eventually we only want to take them if there are other users around as a slow-path. This way sane userspace avoids blocking on edid reads and other stuff in rmfb if it ensures that the fb isn't used anywhere by a crtc/plane.
We can do a quick check for such other users once framebuffers are properly refcounting by locking at the refcount - if it's more than 1, there are other users left. Again, rmfb racing against other ioctls isn't a real problem, userspace is allowed to shoot its foot.
This patch just prepares this by moving the modeset locks to nest within fpriv->fbs_lock. Now the distinction between the fbs_lock and the device-global fb_lock is clear, since we need to hold the fbs_lock outside of any modeset_locks in fb_release.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_crtc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index b6eecd2..b2a845b 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -2282,13 +2282,13 @@ int drm_mode_addfb(struct drm_device *dev, drm_modeset_unlock_all(dev); return PTR_ERR(fb); } + drm_modeset_unlock_all(dev);
mutex_lock(&file_priv->fbs_lock); or->fb_id = fb->base.id; list_add(&fb->filp_head, &file_priv->fbs); DRM_DEBUG_KMS("[FB:%d]\n", fb->base.id); mutex_unlock(&file_priv->fbs_lock); - drm_modeset_unlock_all(dev);
return ret; } @@ -2465,6 +2465,7 @@ int drm_mode_addfb2(struct drm_device *dev, drm_modeset_unlock_all(dev); return PTR_ERR(fb); } + drm_modeset_unlock_all(dev);
mutex_lock(&file_priv->fbs_lock); r->fb_id = fb->base.id; @@ -2472,7 +2473,6 @@ int drm_mode_addfb2(struct drm_device *dev, DRM_DEBUG_KMS("[FB:%d]\n", fb->base.id); mutex_unlock(&file_priv->fbs_lock);
- drm_modeset_unlock_all(dev);
return ret; } @@ -2670,7 +2670,6 @@ void drm_fb_release(struct drm_file *priv) struct drm_device *dev = priv->minor->dev; struct drm_framebuffer *fb, *tfb;
- drm_modeset_lock_all(dev); mutex_lock(&priv->fbs_lock); list_for_each_entry_safe(fb, tfb, &priv->fbs, filp_head) {
@@ -2682,10 +2681,11 @@ void drm_fb_release(struct drm_file *priv) list_del_init(&fb->filp_head);
/* This will also drop the fpriv->fbs reference. */ + drm_modeset_lock_all(dev); drm_framebuffer_remove(fb); + drm_modeset_unlock_all(dev); } mutex_unlock(&priv->fbs_lock); - drm_modeset_unlock_all(dev); }
/**