On Tue, Apr 02, 2019 at 07:29:31AM -0700, Paul E. McKenney wrote: > Having DEFINE_SRCU() or DEFINE_STATIC_SRCU() in a loadable module > requires that the size of the reserved region be increased, which is not > something we really want to be doing. This commit therefore removes > the DEFINE_STATIC_SRCU() from drivers/gpu/drm/drm_drv.c in favor of > defining drm_unplug_srcu as a simple srcu_struct, initializing it in > drm_core_init(), and cleaning it up in drm_core_exit(). > > In this particular case, drm_unplug_srcu is statically allocated and thus > guaranteed to be initially zero. Unfortunately, cleanup_srcu_struct() > cannot rely on this in the general case (which includes dynamically > allocated srcu_struct structures), and therefore cannot tell whether it > is being called on something that has been passed to init_srcu_struct(). > Thus the code added to drm_core_init() is a bit non-standard. > > Reported-by: kbuild test robot <lkp@xxxxxxxxx> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxx> > Cc: Sean Paul <sean@xxxxxxxxxx> > Cc: David Airlie <airlied@xxxxxxxx> > Cc: Daniel Vetter <daniel@xxxxxxxx> > Cc: Tejun Heo <tj@xxxxxxxxxx> > Cc: <dri-devel@xxxxxxxxxxxxxxxxxxxxx> Seems reasonable (but I don't have the full patch series as context). Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Any preferences as to how this should be merged? Upfront ack for merging through rcu trees if that helps you. -Daniel > --- > drivers/gpu/drm/drm_drv.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > index 381581b01d48..ce4582af814d 100644 > --- a/drivers/gpu/drm/drm_drv.c > +++ b/drivers/gpu/drm/drm_drv.c > @@ -77,7 +77,7 @@ static bool drm_core_init_complete = false; > > static struct dentry *drm_debugfs_root; > > -DEFINE_STATIC_SRCU(drm_unplug_srcu); > +static struct srcu_struct drm_unplug_srcu; > > /* > * DRM Minors > @@ -958,12 +958,18 @@ static void drm_core_exit(void) > drm_sysfs_destroy(); > idr_destroy(&drm_minors_idr); > drm_connector_ida_destroy(); > + cleanup_srcu_struct(&drm_unplug_srcu); > } > > static int __init drm_core_init(void) > { > int ret; > > + ret = init_srcu_struct(&drm_unplug_srcu); > + if (ret) { > + DRM_ERROR("Cannot create DRM class: %d\n", ret); > + return ret; /* cannot cleanup after failed srcu_struct init. */ > + } > drm_connector_ida_init(); > idr_init(&drm_minors_idr); > > -- > 2.17.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch