Commit 988fcafc authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c1ff073c

include/qemu/seqlock.h

+20 −0
Original line number Diff line number Diff line
@@ -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.  */