From f643e469f31df735fd5c42ab317f96ebfe749871 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 27 Sep 2016 16:18:34 +0100 Subject: [PATCH] coroutine: add qemu_coroutine_entered() function See the doc comments for a description of this new coroutine API. Signed-off-by: Stefan Hajnoczi Reviewed-by: Fam Zheng Message-id: 1474989516-18255-2-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi --- 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 29a20782f0..e6a60d55fd 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 3cbf225487..737bffa984 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; +}