Re: [PATCH 1/3] coroutine: Add qemu_co_mutex_assert_locked()

[Denis Lunev]

On 10/23/19 6:26 PM, Kevin Wolf wrote:
> Some functions require that the caller holds a certain CoMutex for them
> to operate correctly. Add a function so that they can assert the lock is
> really held.
>
> Cc: address@hidden
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  include/qemu/coroutine.h | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
> index 9801e7f5a4..a36bcfe5c8 100644
> --- a/include/qemu/coroutine.h
> +++ b/include/qemu/coroutine.h
> @@ -167,6 +167,13 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
>   */
>  void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
>  
> +/**
> + * Assert that the current coroutine holds @mutex.
> + */
> +static inline coroutine_fn void qemu_co_mutex_assert_locked(CoMutex *mutex)
> +{
> +    assert(mutex->locked && mutex->holder == qemu_coroutine_self());
> +}
>  
>  /**
>   * CoQueues are a mechanism to queue coroutines in order to continue 
> executing
I think that we should use atomic_read(&mutex->locked) and require barriers
working with holder.

Den