Module: xenomai-forge
Branch: next
Commit: 7ed0572c6b80d700d56a676337c8a3828eadce65
URL:
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=7ed0572c6b80d700d56a676337c8a3828eadce65
Author: Philippe Gerum <r...@xenomai.org>
Date: Thu May 22 15:16:54 2014 +0200
copperplate/internal: reorder head code for copperplate_create_thread()
Once the prologue handler has run successfully from the thread
trampoline, the client code may assume that we can't fail spawning the
child thread anymore, which guarantees that copperplate_create_thread()
will return a success code after this point.
This way, any thread finalizer installed by the prologue handler won't
conflict with the cleanup code the client may run whenever
copperplate_create_thread() fails.
---
lib/copperplate/internal.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/lib/copperplate/internal.c b/lib/copperplate/internal.c
index b57b529..a0c158a 100644
--- a/lib/copperplate/internal.c
+++ b/lib/copperplate/internal.c
@@ -194,23 +194,33 @@ static void *thread_trampoline(void *arg)
* structure early on.
*/
_cta = *cta;
- ret = cta->prologue(cta->arg);
- cta->__reserved.status = ret;
- if (ret)
- goto fail;
ret = __bt(-__RT(sem_init(&released, 0, 0)));
if (ret) {
ret = -errno;
cta->__reserved.status = ret;
+ warning("lack of resources for core thread, %s", symerror(ret));
goto fail;
}
cta->__reserved.released = &released;
+ ret = cta->prologue(cta->arg);
+ cta->__reserved.status = ret;
+ if (ret) {
+ __RT(sem_destroy(&released));
+ backtrace_check();
+ goto fail;
+ }
+
/*
- * CAUTION: over Cobalt, we have to switch back to primary
- * mode _before_ releasing the parent thread, so that proper
- * priority rules apply between the parent and child threads.
+ * CAUTION: Once the prologue handler has run successfully,
+ * the client code may assume that we can't fail spawning the
+ * child thread anymore, which guarantees that
+ * copperplate_create_thread() will return a success code
+ * after this point. This is important so that any thread
+ * finalizer installed by the prologue handler won't conflict
+ * with the cleanup code the client may run whenever
+ * copperplate_create_thread() fails.
*/
prepare_wait_corespec();
__RT(sem_post(&cta->__reserved.warm));
@@ -223,7 +233,6 @@ static void *thread_trampoline(void *arg)
return _cta.run(_cta.arg);
fail:
- backtrace_check();
__RT(sem_post(&cta->__reserved.warm));
return (void *)(long)ret;
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