Hi. This remains unfixed. On 8/4/20, Emmanuel Vadot <[email protected]> wrote: > On Tue, 4 Aug 2020 13:11:02 -0500 > Alan Cox <[email protected]> wrote: > >> >> On 8/4/20 10:25 AM, Emmanuel Vadot wrote: >> > Author: manu >> > Date: Tue Aug 4 15:25:22 2020 >> > New Revision: 363842 >> > URL: https://svnweb.freebsd.org/changeset/base/363842 >> > >> > Log: >> > linuxkpi: Add clear_bit_unlock >> > >> > This calls clear_bit and adds a memory barrier. >> > >> > Sponsored by: The FreeBSD Foundation >> > >> > Reviewed by: hselasky >> > MFC after: 1 week >> > Differential Revision: https://reviews.freebsd.org/D25943 >> > >> > Modified: >> > head/sys/compat/linuxkpi/common/include/linux/bitops.h >> > >> > Modified: head/sys/compat/linuxkpi/common/include/linux/bitops.h >> > ============================================================================== >> > --- head/sys/compat/linuxkpi/common/include/linux/bitops.h Tue Aug 4 >> > 15:00:02 2020 (r363841) >> > +++ head/sys/compat/linuxkpi/common/include/linux/bitops.h Tue Aug 4 >> > 15:25:22 2020 (r363842) >> > @@ -275,6 +275,13 @@ find_next_zero_bit(const unsigned long *addr, >> > unsigned >> > #define test_bit(i, a) >> > \ >> > !!(READ_ONCE(((volatile const unsigned long *)(a))[BIT_WORD(i)]) & >> > BIT_MASK(i)) >> > >> > +static inline void >> > +clear_bit_unlock(long bit, volatile unsigned long *var) >> > +{ >> > + clear_bit(bit, var); >> > + wmb(); >> >> >> For an unlock operation, the memory barrier should come before the >> clear_bit() call, not after. See, for example, the alpha implementation >> in Linux. Also, the correct "spelling" for this memory barrier in >> FreeBSD would be atomic_thread_fence_rel(). See, for example, the >> comment at the top of sys/amd64/include/atomic.h. > > Ah yes, thanks. I probably got lost looking for the linux implem but > that does make sense, I'll fix that probably tomorow. > > Thanks. > >> >> > +} >> > + >> > static inline int >> > test_and_clear_bit(long bit, volatile unsigned long *var) >> > { > > > -- > Emmanuel Vadot <[email protected]> <[email protected]> >
-- Mateusz Guzik <mjguzik gmail.com> _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
