[v2,1/3] coroutine: add qemu_coroutine_entered() function

Commit Message

Stefan Hajnoczi Sept. 27, 2016, 3:18 p.m. UTC

See the doc comments for a description of this new coroutine API.

Signed-off-by: Stefan Hajnoczi <[e-mail]>
---
 include/qemu/coroutine.h | 13 +++++++++++++
 util/qemu-coroutine.c    |  5 +++++
 2 files changed, 18 insertions(+)

Comments

Fam Zheng Sept. 28, 2016, 2:19 a.m. UTC | #1

On Tue, 09/27 16:18, Stefan Hajnoczi wrote:
> See the doc comments for a description of this new coroutine API.
> 
> Signed-off-by: Stefan Hajnoczi <[e-mail]>
> ---
>  include/qemu/coroutine.h | 13 +++++++++++++
>  util/qemu-coroutine.c    |  5 +++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
> index 29a2078..e6a60d5 100644
> --- a/include/qemu/coroutine.h
> +++ b/include/qemu/coroutine.h
> @@ -92,6 +92,19 @@ Coroutine *coroutine_fn qemu_coroutine_self(void);
>   */
>  bool qemu_in_coroutine(void);
>  
> +/**
> + * Return true if the coroutine is currently entered
> + *
> + * A coroutine is "entered" if it has not yielded from the current
> + * qemu_coroutine_enter() call used to run it.  This does not mean that the
> + * coroutine is currently executing code since it may have transferred control
> + * to another coroutine using qemu_coroutine_enter().
> + *
> + * When several coroutines enter each other there may be no way to know which
> + * ones have already been entered.  In such situations this function can be
> + * used to avoid recursively entering coroutines.
> + */
> +bool qemu_coroutine_entered(Coroutine *co);
>  
>  
>  /**
> diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
> index 3cbf225..737bffa 100644
> --- a/util/qemu-coroutine.c
> +++ b/util/qemu-coroutine.c
> @@ -146,3 +146,8 @@ void coroutine_fn qemu_coroutine_yield(void)
>      self->caller = NULL;
>      qemu_coroutine_switch(self, to, COROUTINE_YIELD);
>  }
> +
> +bool qemu_coroutine_entered(Coroutine *co)
> +{
> +    return co->caller;
> +}
> -- 
> 2.7.4
> 

Reviewed-by: Fam Zheng <[e-mail]>

Patch

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 29a2078..e6a60d5 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -92,6 +92,19 @@  Coroutine *coroutine_fn qemu_coroutine_self(void);
  */
 bool qemu_in_coroutine(void);
 
+/**
+ * Return true if the coroutine is currently entered
+ *
+ * A coroutine is "entered" if it has not yielded from the current
+ * qemu_coroutine_enter() call used to run it.  This does not mean that the
+ * coroutine is currently executing code since it may have transferred control
+ * to another coroutine using qemu_coroutine_enter().
+ *
+ * When several coroutines enter each other there may be no way to know which
+ * ones have already been entered.  In such situations this function can be
+ * used to avoid recursively entering coroutines.
+ */
+bool qemu_coroutine_entered(Coroutine *co);
 
 
 /**
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index 3cbf225..737bffa 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -146,3 +146,8 @@  void coroutine_fn qemu_coroutine_yield(void)
     self->caller = NULL;
     qemu_coroutine_switch(self, to, COROUTINE_YIELD);
 }
+
+bool qemu_coroutine_entered(Coroutine *co)
+{
+    return co->caller;
+}