Messages in this thread | | | Date | Sat, 22 Feb 2014 09:38:59 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK |
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Hey,
On Fri, Feb 21, 2014 at 06:46:24PM -0500, Peter Hurley wrote: > It's a long story but the short version is that > Documentation/memory-barriers.txt recently was overhauled to reflect > what cpus actually do and what the different archs actually > deliver. > > Turns out that unlock + lock is not guaranteed by all archs to be > a full barrier. Thus the smb_mb__after_unlock_lock(). > > This is now all spelled out in memory-barriers.txt under the > sub-heading "IMPLICIT KERNEL MEMORY BARRIERS".
So, that one is for unlock/lock sequence, not smp_mb__after_unlock(). Urgh... kinda dislike adding smp_rmb() there as it's one of the barriers which translate to something weighty on most, if not all, archs.
Thanks.
-- tejun
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