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seqlock: add QemuLockable support 

A shortcut when the seqlock write is protected by a spinlock or any mutex
other than the BQL.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2018-08-14 09:48:29 +02:00
parent c1ff073cd8
commit 988fcafc73
1 changed files with 20 additions and 0 deletions
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20
include/qemu/seqlock.h
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@ -16,6 +16,7 @@
#include "qemu/atomic.h"
#include "qemu/thread.h"
#include "qemu/lockable.h"
typedef struct QemuSeqLock QemuSeqLock;
@ -45,6 +46,25 @@ static inline void seqlock_write_end(QemuSeqLock *sl)
atomic_set(&sl->sequence, sl->sequence + 1);
}
/* Lock out other writers and update the count. */
static inline void seqlock_write_lock_impl(QemuSeqLock *sl, QemuLockable *lock)
{
qemu_lockable_lock(lock);
seqlock_write_begin(sl);
}
#define seqlock_write_lock(sl, lock) \
seqlock_write_lock_impl(sl, QEMU_MAKE_LOCKABLE(lock))
/* Lock out other writers and update the count. */
static inline void seqlock_write_unlock_impl(QemuSeqLock *sl, QemuLockable *lock)
{
qemu_lockable_unlock(lock);
seqlock_write_begin(sl);
}
#define seqlock_write_unlock(sl, lock) \
seqlock_write_unlock_impl(sl, QEMU_MAKE_LOCKABLE(lock))
static inline unsigned seqlock_read_begin(const QemuSeqLock *sl)
{
/* Always fail if a write is in progress. */