And drop it where it's not needed. Most driver just lookup the gem object, allocate an fb struct, fill in all the useful fields and then register it with drm_framebuffer_init.
All of these operations are already separately locked, and since we only put the fb into the fpriv->fbs list _after_ having called ->fb_create, we can't also race with rmfb. We can otoh race with other ioctls that put the framebuffer to use, but all drivers have been reorganized already to call drm_framebuffer_init last in the fb creation sequence.
So essentially, we can completely remove any modeset locks from the addfb ioctl paths. Yeah!
Also, reference-counting is solid - we get a reference from fb_create which we transfer to the fpriv->fbs list. And after unlocking the fpriv->fbs_lock we don't touch the framebuffer any longer. Furthermore drm_framebuffer_init has added a 2nd reference for the idr lookup, and any access through that table will do it's own refcounting.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_crtc.c | 9 --------- 1 file changed, 9 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index b2a845b..60d6d87 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -2271,18 +2271,12 @@ int drm_mode_addfb(struct drm_device *dev, if ((config->min_height > r.height) || (r.height > config->max_height)) return -EINVAL;
- drm_modeset_lock_all(dev); - - /* TODO check buffer is sufficiently large */ - /* TODO setup destructor callback */ - fb = dev->mode_config.funcs->fb_create(dev, file_priv, &r); if (IS_ERR(fb)) { DRM_DEBUG_KMS("could not create framebuffer\n"); 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; @@ -2457,15 +2451,12 @@ int drm_mode_addfb2(struct drm_device *dev, if (ret) return ret;
- drm_modeset_lock_all(dev); - fb = dev->mode_config.funcs->fb_create(dev, file_priv, r); if (IS_ERR(fb)) { DRM_DEBUG_KMS("could not create framebuffer\n"); 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;