From 85e16aec51c343f64601b70a6081def69b9f87bc Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Wed, 14 Oct 2020 19:07:27 -0400 Subject: drop use of pthread_once in timer_create this makes the code slightly smaller and eliminates timer_create from relevance to possible future changes to multithreaded fork. the barrier of a_store isn't technically needed here, but a_store is used anyway for internal consistency of the memory model. --- src/time/timer_create.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/src/time/timer_create.c b/src/time/timer_create.c index 2b1ea170..5ddfda27 100644 --- a/src/time/timer_create.c +++ b/src/time/timer_create.c @@ -2,6 +2,7 @@ #include #include #include "pthread_impl.h" +#include "atomic.h" struct ksigevent { union sigval sigev_value; @@ -32,14 +33,6 @@ static void cleanup_fromsig(void *p) longjmp(p, 1); } -static void install_handler() -{ - struct sigaction sa = { - .sa_handler = SIG_DFL, - }; - __libc_sigaction(SIGTIMER, &sa, 0); -} - static void *start(void *arg) { pthread_t self = __pthread_self(); @@ -66,7 +59,7 @@ static void *start(void *arg) int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res) { - static pthread_once_t once = PTHREAD_ONCE_INIT; + volatile static int init = 0; pthread_t td; pthread_attr_t attr; int r; @@ -90,7 +83,11 @@ int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict *res = (void *)(intptr_t)timerid; break; case SIGEV_THREAD: - pthread_once(&once, install_handler); + if (!init) { + struct sigaction sa = { .sa_handler = SIG_DFL }; + __libc_sigaction(SIGTIMER, &sa, 0); + a_store(&init, 1); + } if (evp->sigev_notify_attributes) attr = *evp->sigev_notify_attributes; else -- cgit v1.2.1