Messages in this thread | | | Date | Thu, 28 Jun 2018 21:07:42 +0900 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 1/7] atomics/tty: add missing atomic_long_t * cast |
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On Fri, Jun 22, 2018 at 05:55:59PM +0100, Mark Rutland wrote: > Hi, > > On Wed, Jun 06, 2018 at 04:00:42PM +0200, Greg Kroah-Hartman wrote: > > 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 <peter@hurleysoftware.com> > > > Reported-by: Mark Rutland <mark.rutland@arm.com> > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > > > Looks good, I'll queue this up after 4.18-rc1 is out, thanks. > > Now that v4.18-rc1 is out, I thought I'd ping so that this doesn't get > forgotten.
Not forgotten, sorry, now queued up.
greg k-h
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