Messages in this thread | | | Subject | Re: [PATCH 2/2] ipc/sem.c: Remove duplicated memory barriers. | From | Manfred Spraul <> | Date | Wed, 13 Jul 2016 20:37:33 +0200 |
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Hi Davidlohr,
On 07/13/2016 06:16 PM, Davidlohr Bueso wrote: > Manfred, shouldn't this patch be part of patch 1 (as you add the > unnecessary barriers there? Iow, can we have a single patch for all this? > Two reasons: - patch 1 is safe for backporting, patch 2 not. - patch 1 is safe on all architectures, for patch 2 I would like to get some review feedback.
e.g. I just found/read 51d7d5205d33 ("powerpc: Add smp_mb() to arch_spin_is_locked()"): For powerpc, a smp_mb() was added into spin_is_locked(), more or less for ipc/sem.c.
Patch 1 replaces the spin_is_locked() with smp_load_acquire(). Isn't that the proof that smp_mb() is required?
-- Manfred
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