Module: xenomai-3
Branch: master
Commit: 19309fb17f1640e75af4c1d64162c2de350d4cc3
URL:    
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=19309fb17f1640e75af4c1d64162c2de350d4cc3

Author: Philippe Gerum <r...@xenomai.org>
Date:   Mon May 18 20:36:38 2015 +0200

copperplate/timerobj: do not hold any mutex while intentionally sleeping

CONFIG_XENO_OPT_DEBUG_USER triggers a warning signal as we call
copperplate_create_thread() while holding a mutex, since the former
waits briefly for synchronizing with the child thread.

Use pthread_once() construct instead, which is more appropriate in
this context.

---

 lib/copperplate/timerobj.c |   22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/lib/copperplate/timerobj.c b/lib/copperplate/timerobj.c
index fbe5b0a..bbfa8f2 100644
--- a/lib/copperplate/timerobj.c
+++ b/lib/copperplate/timerobj.c
@@ -140,16 +140,9 @@ static void *timerobj_server(void *arg)
        return NULL;
 }
 
-static int timerobj_spawn_server(void)
+static void timerobj_spawn_server(void)
 {
        struct corethread_attributes cta;
-       int ret = 0;
-
-       push_cleanup_lock(&svlock);
-       write_lock(&svlock);
-
-       if (svthread)
-               goto out;
 
        cta.policy = SCHED_CORE;
        cta.param_ex.sched_priority = threadobj_irq_prio;
@@ -158,16 +151,13 @@ static int timerobj_spawn_server(void)
        cta.arg = NULL;
        cta.stacksize = PTHREAD_STACK_MIN * 16;
        cta.detachstate = PTHREAD_CREATE_DETACHED;
-       ret = __bt(copperplate_create_thread(&cta, &svthread));
-out:
-       write_unlock(&svlock);
-       pop_cleanup_lock(&svlock);
 
-       return ret;
+       __bt(copperplate_create_thread(&cta, &svthread));
 }
 
 int timerobj_init(struct timerobj *tmobj)
 {
+       static pthread_once_t spawn_once;
        pthread_mutexattr_t mattr;
        struct sigevent sev;
        int ret;
@@ -183,9 +173,9 @@ int timerobj_init(struct timerobj *tmobj)
         * very least), and spawning a short-lived thread at each
         * timeout expiration to run the handler is just overkill.
         */
-       ret = timerobj_spawn_server();
-       if (ret)
-               return __bt(ret);
+       pthread_once(&spawn_once, timerobj_spawn_server);
+       if (!svthread)
+               return __bt(-EAGAIN);
 
        tmobj->handler = NULL;
        pvholder_init(&tmobj->next); /* so we may use pvholder_linked() */


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