make linking of thread-start with explicit scheduling conditional

the wrapper start function that performs scheduling operations is
unreachable if pthread_attr_setinheritsched is never called, so move
it there rather than the pthread_create source file, saving some code
size for static-linked programs.

1 files changed, 21 insertions, 0 deletions

diff --git a/src/thread/pthread_attr_setinheritsched.c b/src/thread/pthread_attr_setinheritsched.c
index c91d8f83..e540e846 100644
--- a/src/thread/pthread_attr_setinheritsched.c
+++ b/src/thread/pthread_attr_setinheritsched.c
@@ -1,4 +1,25 @@
 #include "pthread_impl.h"
+#include "syscall.h"
+
+__attribute__((__visibility__("hidden")))
+void *__start_sched(void *p)
+{
+	struct start_sched_args *ssa = p;
+	void *start_arg = ssa->start_arg;
+	void *(*start_fn)(void *) = ssa->start_fn;
+	pthread_t self = __pthread_self();
+
+	int ret = -__syscall(SYS_sched_setscheduler, self->tid,
+		ssa->attr->_a_policy, &ssa->attr->_a_prio);
+	if (!ret) __restore_sigs(&ssa->mask);
+	a_store(&ssa->futex, ret);
+	__wake(&ssa->futex, 1, 1);
+	if (ret) {
+		self->detach_state = DT_DYNAMIC;
+		return 0;
+	}
+	return start_fn(start_arg);
+}
 
 int pthread_attr_setinheritsched(pthread_attr_t *a, int inherit)
 {