#ifndef QEMU_SEQLOCK_H
#define QEMU_SEQLOCK_H 1
-#include <qemu/atomic.h>
-#include <qemu/thread.h>
+#include "qemu/atomic.h"
+#include "qemu/thread.h"
typedef struct QemuSeqLock QemuSeqLock;
struct QemuSeqLock {
- QemuMutex *mutex;
unsigned sequence;
};
-static inline void seqlock_init(QemuSeqLock *sl, QemuMutex *mutex)
+static inline void seqlock_init(QemuSeqLock *sl)
{
- sl->mutex = mutex;
sl->sequence = 0;
}
/* Lock out other writers and update the count. */
-static inline void seqlock_write_lock(QemuSeqLock *sl)
+static inline void seqlock_write_begin(QemuSeqLock *sl)
{
- if (sl->mutex) {
- qemu_mutex_lock(sl->mutex);
- }
++sl->sequence;
/* Write sequence before updating other fields. */
smp_wmb();
}
-static inline void seqlock_write_unlock(QemuSeqLock *sl)
+static inline void seqlock_write_end(QemuSeqLock *sl)
{
/* Write other fields before finalizing sequence. */
smp_wmb();
++sl->sequence;
- if (sl->mutex) {
- qemu_mutex_unlock(sl->mutex);
- }
}
static inline unsigned seqlock_read_begin(QemuSeqLock *sl)
{
/* Always fail if a write is in progress. */
- unsigned ret = sl->sequence & ~1;
+ unsigned ret = atomic_read(&sl->sequence);
/* Read sequence before reading other fields. */
smp_rmb();
- return ret;
+ return ret & ~1;
}
-static int seqlock_read_retry(const QemuSeqLock *sl, unsigned start)
+static inline int seqlock_read_retry(const QemuSeqLock *sl, unsigned start)
{
/* Read other fields before reading final sequence. */
smp_rmb();
- return unlikely(sl->sequence != start);
+ return unlikely(atomic_read(&sl->sequence) != start);
}
#endif