On Thu, Apr 21, 2022 at 08:33:18AM -0700, Dan Williams wrote: > The CXL "root" device, ACPI0017, is an attach point for coordinating > platform level CXL resources and is the parent device for a CXL port > topology tree. As such it has distinct locking rules relative to other > CXL subsystem objects, but because it is an ACPI device the lock class > is established well before it is given to the cxl_acpi driver. > > However, the lockdep API does support changing the lock class "live" for > situations like this. Add a device_lock_set_class() helper that a driver > can use in ->probe() to set a custom lock class, and > device_lock_reset_class() to return to the default "no validate" class > before the custom lock class key goes out of scope after ->remove(). > > Note the helpers are all macros to support dead code elimination in the > CONFIG_PROVE_LOCKING=n case. > > Suggested-by: Peter Zijlstra <pet...@infradead.org> > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Cc: "Rafael J. Wysocki" <raf...@kernel.org> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Will Deacon <w...@kernel.org> > Cc: Waiman Long <long...@redhat.com> > Cc: Boqun Feng <boqun.f...@gmail.com> > Cc: Alison Schofield <alison.schofi...@intel.com> > Cc: Vishal Verma <vishal.l.ve...@intel.com> > Cc: Ira Weiny <ira.we...@intel.com> > Cc: Ben Widawsky <ben.widaw...@intel.com> > Cc: Jonathan Cameron <jonathan.came...@huawei.com> > Signed-off-by: Dan Williams <dan.j.willi...@intel.com> > --- > drivers/cxl/acpi.c | 15 +++++++++++++++ > include/linux/device.h | 25 +++++++++++++++++++++++++ > 2 files changed, 40 insertions(+)
Much simpler, great work. Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
