On Tue, Jun 05, 2018 at 04:53:34PM +0200, Peter Zijlstra wrote: > On Tue, Jun 05, 2018 at 04:43:04PM +0200, Peter Zijlstra wrote: > > > I can make a proper patch, hold on. > > --- > Subject: atomic/tty: Fix up atomic abuse in ldsem > > Mark found ldsem_cmpxchg() needed an (atomic_long_t *) cast to keep > working after making the atomic_long interface type safe. > > Needing casts is bad form, which made me look at the code. There are no > ld_semaphore::count users outside of these functions so there is no > reason why it can not be an atomic_long_t in the first place, obviating > the need for this cast. > > That also ensures the loads use atomic_long_read(), which implies (at > least) READ_ONCE() in order to guarantee single-copy-atomic loads. > > When using atomic_long_try_cmpxchg() the ldsem_cmpxchg() wrapper gets > very thin (the only difference is not changing *old on success, which > most callers don't seem to care about). > > So rework the whole thing to use atomic_long_t and its accessors > directly. > > While there, fixup all the horrible comment styles. > > Cc: Peter Hurley <pe...@hurleysoftware.com> > Reported-by: Mark Rutland <mark.rutl...@arm.com> > Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Looks good, I'll queue this up after 4.18-rc1 is out, thanks. greg k-h
