Messages in this thread | | | Date | Fri, 22 Jun 2018 17:55:59 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 1/7] atomics/tty: add missing atomic_long_t * cast |
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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.
Have a good weekend!
Mark.
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