On Mon, Dec 07, 2020 at 03:25:00PM -0300, Martin Pieuchot wrote: > Simple diff below to add the rw_lock_held() as well as a read & write > version. > > This allows us to reduce the difference with NetBSD in UVM by adding the > following checks: > > KASSERT(rw_write_held(amap->am_lock)); > > ok? > > Index: sys/rwlock.h > =================================================================== > RCS file: /cvs/src/sys/sys/rwlock.h,v > retrieving revision 1.26 > diff -u -p -r1.26 rwlock.h > --- sys/rwlock.h 16 Jul 2019 01:40:49 -0000 1.26 > +++ sys/rwlock.h 7 Dec 2020 18:22:03 -0000 > @@ -168,6 +168,11 @@ int rw_enter(struct rwlock *, int); > void rw_exit(struct rwlock *); > int rw_status(struct rwlock *); > > +#define rw_read_held(rwl) (rw_status(rwl) == RW_READ) > +#define rw_write_held(rwl) (rw_status(rwl) == RW_WRITE) > +#define rw_lock_held(rwl) (rw_write_held(rwl) || > rw_read_held(rwl))
I think rw_lock_held() should invoke rw_status() only once. This would reduce the overhead. It could even be a proper C function. > + > + > void _rrw_init_flags(struct rrwlock *, const char *, int, > const struct lock_type *); > int rrw_enter(struct rrwlock *, int); >
