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Viewing changes to include/linux/seqlock.h

  • Committer: Bazaar Package Importer
  • Author(s): Paolo Pisati
  • Date: 2011-06-29 15:23:51 UTC
  • mfrom: (26.1.1 natty-proposed)
  • Revision ID: james.westby@ubuntu.com-20110629152351-xs96tm303d95rpbk
Tags: 3.0.0-1200.2
* Rebased against 3.0.0-6.7
* BSP from TI based on 3.0.0

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include/linux/seqlock.h
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#include <linux/spinlock.h>
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#include <linux/preempt.h>
 
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#include <asm/processor.h>
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typedef struct {
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        unsigned sequence;
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#define __SEQLOCK_UNLOCKED(lockname) \
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                 { 0, __SPIN_LOCK_UNLOCKED(lockname) }
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#define SEQLOCK_UNLOCKED \
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                 __SEQLOCK_UNLOCKED(old_style_seqlock_init)
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#define seqlock_init(x)                                 \
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        do {                                            \
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                (x)->sequence = 0;                      \
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        unsigned ret;
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repeat:
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        ret = sl->sequence;
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        smp_rmb();
 
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        ret = ACCESS_ONCE(sl->sequence);
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        if (unlikely(ret & 1)) {
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                cpu_relax();
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                goto repeat;
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        }
 
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        smp_rmb();
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        return ret;
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}