From 0fc317d83c1167393bf276a8bfbdd9a4e02e8258 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 2 Mar 2015 17:46:22 -0500 Subject: factor cancellation cleanup push/pop out of futex __timedwait function previously, the __timedwait function was optionally a cancellation point depending on whether it was passed a pointer to a cleaup function and context to register. as of now, only one caller actually used such a cleanup function (and it may face removal soon); most callers either passed a null pointer to disable cancellation or a dummy cleanup function. now, __timedwait is never a cancellation point, and __timedwait_cp is the cancellable version. this makes the intent of the calling code more obvious and avoids ugly dummy functions and long argument lists. --- src/aio/aio_suspend.c | 2 +- src/internal/pthread_impl.h | 3 ++- src/thread/__timedwait.c | 22 +++++++++++++--------- src/thread/pthread_cond_timedwait.c | 6 +----- src/thread/pthread_join.c | 6 +----- src/thread/pthread_mutex_timedlock.c | 2 +- src/thread/pthread_rwlock_timedrdlock.c | 2 +- src/thread/pthread_rwlock_timedwrlock.c | 2 +- src/thread/sem_timedwait.c | 5 +++-- 9 files changed, 24 insertions(+), 26 deletions(-) (limited to 'src') diff --git a/src/aio/aio_suspend.c b/src/aio/aio_suspend.c index 2391d786..dfa524bf 100644 --- a/src/aio/aio_suspend.c +++ b/src/aio/aio_suspend.c @@ -61,7 +61,7 @@ int aio_suspend(const struct aiocb *const cbs[], int cnt, const struct timespec break; } - ret = __timedwait(pfut, expect, CLOCK_MONOTONIC, ts?&at:0, 0, 0, 1); + ret = __timedwait(pfut, expect, CLOCK_MONOTONIC, ts?&at:0, 1); if (ret) { errno = ret==ETIMEDOUT ? EAGAIN : ret; diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index ae6e60b5..7e7baa90 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -107,7 +107,8 @@ int __libc_sigprocmask(int, const sigset_t *, sigset_t *); void __lock(volatile int *); void __unmapself(void *, size_t); -int __timedwait(volatile int *, int, clockid_t, const struct timespec *, void (*)(void *), void *, int); +int __timedwait(volatile int *, int, clockid_t, const struct timespec *, int); +int __timedwait_cp(volatile int *, int, clockid_t, const struct timespec *, int); void __wait(volatile int *, volatile int *, int, int); static inline void __wake(volatile void *addr, int cnt, int priv) { diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c index 9b882b5a..13d8465a 100644 --- a/src/thread/__timedwait.c +++ b/src/thread/__timedwait.c @@ -3,15 +3,15 @@ #include #include "futex.h" #include "syscall.h" +#include "pthread_impl.h" int __pthread_setcancelstate(int, int *); int __clock_gettime(clockid_t, struct timespec *); -int __timedwait(volatile int *addr, int val, - clockid_t clk, const struct timespec *at, - void (*cleanup)(void *), void *arg, int priv) +int __timedwait_cp(volatile int *addr, int val, + clockid_t clk, const struct timespec *at, int priv) { - int r, cs; + int r; struct timespec to, *top=0; if (priv) priv = 128; @@ -28,15 +28,19 @@ int __timedwait(volatile int *addr, int val, top = &to; } - if (!cleanup) __pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); - pthread_cleanup_push(cleanup, arg); - r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT|priv, val, top); if (r == ENOSYS) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top); if (r != EINTR && r != ETIMEDOUT && r != ECANCELED) r = 0; - pthread_cleanup_pop(0); - if (!cleanup) __pthread_setcancelstate(cs, 0); + return r; +} +int __timedwait(volatile int *addr, int val, + clockid_t clk, const struct timespec *at, int priv) +{ + int cs, r; + __pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs); + r = __timedwait_cp(addr, val, clk, at, priv); + __pthread_setcancelstate(cs, 0); return r; } diff --git a/src/thread/pthread_cond_timedwait.c b/src/thread/pthread_cond_timedwait.c index adf9c6e5..f5fd08c0 100644 --- a/src/thread/pthread_cond_timedwait.c +++ b/src/thread/pthread_cond_timedwait.c @@ -64,10 +64,6 @@ enum { LEAVING, }; -static void dummy(void *arg) -{ -} - int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restrict m, const struct timespec *restrict ts) { struct waiter node = { 0 }; @@ -104,7 +100,7 @@ int __pthread_cond_timedwait(pthread_cond_t *restrict c, pthread_mutex_t *restri __pthread_setcancelstate(PTHREAD_CANCEL_MASKED, &cs); - do e = __timedwait(fut, seq, clock, ts, dummy, 0, !shared); + do e = __timedwait_cp(fut, seq, clock, ts, !shared); while (*fut==seq && (!e || e==EINTR)); if (e == EINTR) e = 0; diff --git a/src/thread/pthread_join.c b/src/thread/pthread_join.c index 19e6b548..b4ff33a5 100644 --- a/src/thread/pthread_join.c +++ b/src/thread/pthread_join.c @@ -3,15 +3,11 @@ int __munmap(void *, size_t); -static void dummy(void *p) -{ -} - int __pthread_join(pthread_t t, void **res) { int tmp; pthread_testcancel(); - while ((tmp = t->tid)) __timedwait(&t->tid, tmp, 0, 0, dummy, 0, 0); + while ((tmp = t->tid)) __timedwait_cp(&t->tid, tmp, 0, 0, 0); if (res) *res = t->result; if (t->map_base) __munmap(t->map_base, t->map_size); return 0; diff --git a/src/thread/pthread_mutex_timedlock.c b/src/thread/pthread_mutex_timedlock.c index 16241eeb..0a240e79 100644 --- a/src/thread/pthread_mutex_timedlock.c +++ b/src/thread/pthread_mutex_timedlock.c @@ -24,7 +24,7 @@ int __pthread_mutex_timedlock(pthread_mutex_t *restrict m, const struct timespec a_inc(&m->_m_waiters); t = r | 0x80000000; a_cas(&m->_m_lock, r, t); - r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, 0, 0, priv); + r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, priv); a_dec(&m->_m_waiters); if (r && r != EINTR) break; } diff --git a/src/thread/pthread_rwlock_timedrdlock.c b/src/thread/pthread_rwlock_timedrdlock.c index ea50da4a..0d5d0d6c 100644 --- a/src/thread/pthread_rwlock_timedrdlock.c +++ b/src/thread/pthread_rwlock_timedrdlock.c @@ -15,7 +15,7 @@ int pthread_rwlock_timedrdlock(pthread_rwlock_t *restrict rw, const struct times t = r | 0x80000000; a_inc(&rw->_rw_waiters); a_cas(&rw->_rw_lock, r, t); - r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, 0, 0, rw->_rw_shared^128); + r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, rw->_rw_shared^128); a_dec(&rw->_rw_waiters); if (r && r != EINTR) return r; } diff --git a/src/thread/pthread_rwlock_timedwrlock.c b/src/thread/pthread_rwlock_timedwrlock.c index 8d04f561..7f26dad1 100644 --- a/src/thread/pthread_rwlock_timedwrlock.c +++ b/src/thread/pthread_rwlock_timedwrlock.c @@ -15,7 +15,7 @@ int pthread_rwlock_timedwrlock(pthread_rwlock_t *restrict rw, const struct times t = r | 0x80000000; a_inc(&rw->_rw_waiters); a_cas(&rw->_rw_lock, r, t); - r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, 0, 0, rw->_rw_shared^128); + r = __timedwait(&rw->_rw_lock, t, CLOCK_REALTIME, at, rw->_rw_shared^128); a_dec(&rw->_rw_waiters); if (r && r != EINTR) return r; } diff --git a/src/thread/sem_timedwait.c b/src/thread/sem_timedwait.c index 288991d4..a7488df7 100644 --- a/src/thread/sem_timedwait.c +++ b/src/thread/sem_timedwait.c @@ -19,8 +19,9 @@ int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict at) int r; a_inc(sem->__val+1); a_cas(sem->__val, 0, -1); - r = __timedwait(sem->__val, -1, CLOCK_REALTIME, at, cleanup, sem->__val+1, sem->__val[2]); - a_dec(sem->__val+1); + pthread_cleanup_push(cleanup, sem->__val+1); + r = __timedwait_cp(sem->__val, -1, CLOCK_REALTIME, at, sem->__val[2]); + pthread_cleanup_pop(1); if (r && r != EINTR) { errno = r; return -1; -- cgit v1.2.1