Re: [Qemu-devel] [RFC PATCH V6 04/18] add support for spin lock on POSIX systems exclusively

[Paolo Bonzini <pbonzini@redhat.com>]

On 26/06/2015 16:47, fred.konrad@greensocs.com wrote:
> From: Guillaume Delbergue <guillaume.delbergue@greensocs.com>
> 
> WARNING: spin lock is currently not implemented on WIN32

The Windows KSPIN_LOCK is a kernel data structure.  You can implement a
simple, portable test-and-test-and-set spinlock using atomics, and use
it on both POSIX and Win32.

Paolo

> Signed-off-by: Guillaume Delbergue <guillaume.delbergue@greensocs.com>
> ---
>  include/qemu/thread-posix.h |  4 ++++
>  include/qemu/thread-win32.h |  4 ++++
>  include/qemu/thread.h       |  7 +++++++
>  util/qemu-thread-posix.c    | 45 +++++++++++++++++++++++++++++++++++++++++++++
>  util/qemu-thread-win32.c    | 30 ++++++++++++++++++++++++++++++
>  5 files changed, 90 insertions(+)
> 
> diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h
> index eb5c7a1..8ce8f01 100644
> --- a/include/qemu/thread-posix.h
> +++ b/include/qemu/thread-posix.h
> @@ -7,6 +7,10 @@ struct QemuMutex {
>      pthread_mutex_t lock;
>  };
>  
> +struct QemuSpin {
> +    pthread_spinlock_t lock;
> +};
> +
>  struct QemuCond {
>      pthread_cond_t cond;
>  };
> diff --git a/include/qemu/thread-win32.h b/include/qemu/thread-win32.h
> index 3d58081..310c8bd 100644
> --- a/include/qemu/thread-win32.h
> +++ b/include/qemu/thread-win32.h
> @@ -7,6 +7,10 @@ struct QemuMutex {
>      LONG owner;
>  };
>  
> +struct QemuSpin {
> +    PKSPIN_LOCK lock;
> +};
> +
>  struct QemuCond {
>      LONG waiters, target;
>      HANDLE sema;
> diff --git a/include/qemu/thread.h b/include/qemu/thread.h
> index 5114ec8..f5d1259 100644
> --- a/include/qemu/thread.h
> +++ b/include/qemu/thread.h
> @@ -5,6 +5,7 @@
>  #include <stdbool.h>
>  
>  typedef struct QemuMutex QemuMutex;
> +typedef struct QemuSpin QemuSpin;
>  typedef struct QemuCond QemuCond;
>  typedef struct QemuSemaphore QemuSemaphore;
>  typedef struct QemuEvent QemuEvent;
> @@ -25,6 +26,12 @@ void qemu_mutex_lock(QemuMutex *mutex);
>  int qemu_mutex_trylock(QemuMutex *mutex);
>  void qemu_mutex_unlock(QemuMutex *mutex);
>  
> +void qemu_spin_init(QemuSpin *spin);
> +void qemu_spin_destroy(QemuSpin *spin);
> +void qemu_spin_lock(QemuSpin *spin);
> +int qemu_spin_trylock(QemuSpin *spin);
> +void qemu_spin_unlock(QemuSpin *spin);
> +
>  void qemu_cond_init(QemuCond *cond);
>  void qemu_cond_destroy(QemuCond *cond);
>  
> diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
> index ba67cec..224bacc 100644
> --- a/util/qemu-thread-posix.c
> +++ b/util/qemu-thread-posix.c
> @@ -89,6 +89,51 @@ void qemu_mutex_unlock(QemuMutex *mutex)
>          error_exit(err, __func__);
>  }
>  
> +void qemu_spin_init(QemuSpin *spin)
> +{
> +    int err;
> +
> +    err = pthread_spin_init(&spin->lock, 0);
> +    if (err) {
> +        error_exit(err, __func__);
> +    }
> +}
> +
> +void qemu_spin_destroy(QemuSpin *spin)
> +{
> +    int err;
> +
> +    err = pthread_spin_destroy(&spin->lock);
> +    if (err) {
> +        error_exit(err, __func__);
> +    }
> +}
> +
> +void qemu_spin_lock(QemuSpin *spin)
> +{
> +    int err;
> +
> +    err = pthread_spin_lock(&spin->lock);
> +    if (err) {
> +        error_exit(err, __func__);
> +    }
> +}
> +
> +int qemu_spin_trylock(QemuSpin *spin)
> +{
> +    return pthread_spin_trylock(&spin->lock);
> +}
> +
> +void qemu_spin_unlock(QemuSpin *spin)
> +{
> +    int err;
> +
> +    err = pthread_spin_unlock(&spin->lock);
> +    if (err) {
> +        error_exit(err, __func__);
> +    }
> +}
> +
>  void qemu_cond_init(QemuCond *cond)
>  {
>      int err;
> diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
> index 406b52f..6fbe6a8 100644
> --- a/util/qemu-thread-win32.c
> +++ b/util/qemu-thread-win32.c
> @@ -80,6 +80,36 @@ void qemu_mutex_unlock(QemuMutex *mutex)
>      LeaveCriticalSection(&mutex->lock);
>  }
>  
> +void qemu_spin_init(QemuSpin *spin)
> +{
> +    printf("spinlock not implemented");
> +    abort();
> +}
> +
> +void qemu_spin_destroy(QemuSpin *spin)
> +{
> +    printf("spinlock not implemented");
> +    abort();
> +}
> +
> +void qemu_spin_lock(QemuSpin *spin)
> +{
> +    printf("spinlock not implemented");
> +    abort();
> +}
> +
> +int qemu_spin_trylock(QemuSpin *spin)
> +{
> +    printf("spinlock not implemented");
> +    abort();
> +}
> +
> +void qemu_spin_unlock(QemuSpin *spin)
> +{
> +    printf("spinlock not implemented");
> +    abort();
> +}
> +
>  void qemu_cond_init(QemuCond *cond)
>  {
>      memset(cond, 0, sizeof(*cond));
>