Module: xenomai-forge
Branch: master
Commit: 072601b0d193b86ee50ec7495eed4b91cc6a5357
URL:
http://git.xenomai.org/?p=xenomai-forge.git;a=commit;h=072601b0d193b86ee50ec7495eed4b91cc6a5357
Author: Philippe Gerum <r...@xenomai.org>
Date: Thu Dec 15 10:30:15 2011 +0100
copperplate/threadobj, lib: fix locking rules of threadobj_set_priority()
Since threadobj_set_priority() must receive the thread lock on entry,
prior to dropping it before applying the priority change via a
syscall, it might be unable to lock it back before returning to the
caller, in case the thread has exited in the meantime.
Instead of attempting to re-lock the object eventually - bluntly
ignoring the operation status - we should rather behave fully as a
lock-dropping call and document it accordingly. Callers should grab
that lock again in case more changes are required (which none of them
currently want anyway).
---
lib/alchemy/task.c | 1 -
lib/copperplate/threadobj.c | 31 +++++++++++++++++--------------
lib/psos/task.c | 1 -
lib/vxworks/taskLib.c | 1 -
4 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/lib/alchemy/task.c b/lib/alchemy/task.c
index e21122e..e627a33 100644
--- a/lib/alchemy/task.c
+++ b/lib/alchemy/task.c
@@ -592,7 +592,6 @@ int rt_task_set_priority(RT_TASK *task, int prio)
goto out;
ret = threadobj_set_priority(&tcb->thobj, prio);
- put_alchemy_task(tcb);
out:
COPPERPLATE_UNPROTECT(svc);
diff --git a/lib/copperplate/threadobj.c b/lib/copperplate/threadobj.c
index 79db06f..7dac280 100644
--- a/lib/copperplate/threadobj.c
+++ b/lib/copperplate/threadobj.c
@@ -272,11 +272,11 @@ int threadobj_unlock_sched(struct threadobj *thobj) /*
thobj->lock held */
return __bt(-ret);
}
-int threadobj_set_priority(struct threadobj *thobj, int prio) /* thobj->lock
held */
+int threadobj_set_priority(struct threadobj *thobj, int prio) /* thobj->lock
held, dropped */
{
struct sched_param_ex xparam;
pthread_t tid = thobj->tid;
- int ret, policy;
+ int policy;
__threadobj_check_locked(thobj);
@@ -297,10 +297,8 @@ int threadobj_set_priority(struct threadobj *thobj, int
prio) /* thobj->lock hel
* set.
*/
xparam.sched_priority = prio;
- ret = pthread_setschedparam_ex(tid, policy, &xparam);
- threadobj_lock(thobj);
- return __bt(-ret);
+ return pthread_setschedparam_ex(tid, policy, &xparam);
}
int threadobj_set_mode(struct threadobj *thobj,
@@ -583,12 +581,14 @@ int threadobj_resume(struct threadobj *thobj) /*
thobj->lock held */
return __bt(notifier_release(&thobj->core.notifier));
}
-int threadobj_lock_sched(struct threadobj *thobj)
+int threadobj_lock_sched(struct threadobj *thobj) /* thobj->lock held */
{
pthread_t tid = thobj->tid;
struct sched_param param;
int policy, ret;
+ __threadobj_check_locked(thobj);
+
assert(thobj == threadobj_current());
if (thobj->schedlock_depth++ > 0)
@@ -606,12 +606,14 @@ int threadobj_lock_sched(struct threadobj *thobj)
return __bt(-pthread_setschedparam(tid, SCHED_RT, ¶m));
}
-int threadobj_unlock_sched(struct threadobj *thobj)
+int threadobj_unlock_sched(struct threadobj *thobj) /* thobj->lock held */
{
pthread_t tid = thobj->tid;
struct sched_param param;
int policy, ret;
+ __threadobj_check_locked(thobj);
+
assert(thobj == threadobj_current());
if (thobj->schedlock_depth == 0)
@@ -631,11 +633,13 @@ int threadobj_unlock_sched(struct threadobj *thobj)
return __bt(-ret);
}
-int threadobj_set_priority(struct threadobj *thobj, int prio)
+int threadobj_set_priority(struct threadobj *thobj, int prio) /* thobj->lock
held, dropped */
{
pthread_t tid = thobj->tid;
struct sched_param param;
- int policy, ret;
+ int policy;
+
+ __threadobj_check_locked(thobj);
/*
* We don't actually change the scheduling priority in case
@@ -647,18 +651,16 @@ int threadobj_set_priority(struct threadobj *thobj, int
prio)
return 0;
}
+ thobj->priority = prio;
threadobj_unlock(thobj);
/*
* Since we released the thread container lock, we now rely on
* the pthread interface to recheck the tid for existence.
*/
- thobj->priority = prio;
param.sched_priority = prio;
policy = prio ? SCHED_RT : SCHED_OTHER;
- ret = pthread_setschedparam(tid, policy, ¶m);
- threadobj_lock(thobj);
- return __bt(-ret);
+ return pthread_setschedparam(tid, policy, ¶m);
}
int threadobj_set_mode(struct threadobj *thobj,
@@ -704,8 +706,9 @@ static inline void set_rr(struct threadobj *thobj, struct
timespec *quantum)
}
int threadobj_set_rr(struct threadobj *thobj, struct timespec *quantum)
-{
+{ /* thobj->lock held if valid */
if (thobj) {
+ __threadobj_check_locked(thobj);
set_rr(thobj, quantum);
return 0;
}
diff --git a/lib/psos/task.c b/lib/psos/task.c
index b790828..ca62c51 100644
--- a/lib/psos/task.c
+++ b/lib/psos/task.c
@@ -425,7 +425,6 @@ u_long t_setpri(u_long tid, u_long newprio, u_long
*oldprio_r)
}
ret = threadobj_set_priority(&task->thobj, cprio);
- put_psos_task(task);
if (ret)
return ERR_OBJDEL;
diff --git a/lib/vxworks/taskLib.c b/lib/vxworks/taskLib.c
index 91ca450..5f42430 100644
--- a/lib/vxworks/taskLib.c
+++ b/lib/vxworks/taskLib.c
@@ -732,7 +732,6 @@ STATUS taskPrioritySet(TASK_ID tid, int prio)
COPPERPLATE_PROTECT(svc);
ret = threadobj_set_priority(&task->thobj, cprio);
COPPERPLATE_UNPROTECT(svc);
- put_wind_task(task);
if (ret) {
objid_error:
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