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take read_seqbegin_or_lock() and friends to seqlock.h

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2013-10-25 16:39:14 -04:00
parent b26d4cd385
commit 2bc74feba1
2 changed files with 29 additions and 29 deletions
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29
fs/dcache.c
View File

@ -88,35 +88,6 @@ EXPORT_SYMBOL(rename_lock);
static struct kmem_cache *dentry_cache __read_mostly; static struct kmem_cache *dentry_cache __read_mostly;
/**
* read_seqbegin_or_lock - begin a sequence number check or locking block
* @lock: sequence lock
* @seq : sequence number to be checked
*
* First try it once optimistically without taking the lock. If that fails,
* take the lock. The sequence number is also used as a marker for deciding
* whether to be a reader (even) or writer (odd).
* N.B. seq must be initialized to an even number to begin with.
*/
static inline void read_seqbegin_or_lock(seqlock_t *lock, int *seq)
{
if (!(*seq & 1)) /* Even */
*seq = read_seqbegin(lock);
else /* Odd */
read_seqlock_excl(lock);
}
static inline int need_seqretry(seqlock_t *lock, int seq)
{
return !(seq & 1) && read_seqretry(lock, seq);
}
static inline void done_seqretry(seqlock_t *lock, int seq)
{
if (seq & 1)
read_sequnlock_excl(lock);
}
/* /*
* This is the single most critical data structure when it comes * This is the single most critical data structure when it comes
* to the dcache: the hashtable for lookups. Somebody should try * to the dcache: the hashtable for lookups. Somebody should try

29
include/linux/seqlock.h
View File

@ -354,6 +354,35 @@ static inline void read_sequnlock_excl(seqlock_t *sl)
spin_unlock(&sl->lock); spin_unlock(&sl->lock);
} }
/**
* read_seqbegin_or_lock - begin a sequence number check or locking block
* @lock: sequence lock
* @seq : sequence number to be checked
*
* First try it once optimistically without taking the lock. If that fails,
* take the lock. The sequence number is also used as a marker for deciding
* whether to be a reader (even) or writer (odd).
* N.B. seq must be initialized to an even number to begin with.
*/
static inline void read_seqbegin_or_lock(seqlock_t *lock, int *seq)
{
if (!(*seq & 1)) /* Even */
*seq = read_seqbegin(lock);
else /* Odd */
read_seqlock_excl(lock);
}
static inline int need_seqretry(seqlock_t *lock, int seq)
{
return !(seq & 1) && read_seqretry(lock, seq);
}
static inline void done_seqretry(seqlock_t *lock, int seq)
{
if (seq & 1)
read_sequnlock_excl(lock);
}
static inline void read_seqlock_excl_bh(seqlock_t *sl) static inline void read_seqlock_excl_bh(seqlock_t *sl)
{ {
spin_lock_bh(&sl->lock); spin_lock_bh(&sl->lock);