diff options
Diffstat (limited to 'libpthread/nptl/pthread_mutex_timedlock.c')
| -rw-r--r-- | libpthread/nptl/pthread_mutex_timedlock.c | 402 |
1 files changed, 384 insertions, 18 deletions
diff --git a/libpthread/nptl/pthread_mutex_timedlock.c b/libpthread/nptl/pthread_mutex_timedlock.c index 6f3df6ff0..a4ee25de0 100644 --- a/libpthread/nptl/pthread_mutex_timedlock.c +++ b/libpthread/nptl/pthread_mutex_timedlock.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. +/* Copyright (C) 2002-2007, 2008 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -17,9 +17,12 @@ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ +#include <assert.h> #include <errno.h> +#include <time.h> #include "pthreadP.h" #include <lowlevellock.h> +#include <not-cancel.h> int @@ -27,13 +30,15 @@ pthread_mutex_timedlock ( pthread_mutex_t *mutex, const struct timespec *abstime) { + int oldval; pid_t id = THREAD_GETMEM (THREAD_SELF, tid); int result = 0; /* We must not check ABSTIME here. If the thread does not block abstime must not be checked for a valid value. */ - switch (mutex->__data.__kind) + switch (__builtin_expect (PTHREAD_MUTEX_TYPE (mutex), + PTHREAD_MUTEX_TIMED_NP)) { /* Recursive mutex. */ case PTHREAD_MUTEX_RECURSIVE_NP: @@ -49,40 +54,38 @@ pthread_mutex_timedlock ( goto out; } - else - { - /* We have to get the mutex. */ - result = lll_mutex_timedlock (mutex->__data.__lock, abstime); - if (result != 0) - goto out; + /* We have to get the mutex. */ + result = lll_timedlock (mutex->__data.__lock, abstime, + PTHREAD_MUTEX_PSHARED (mutex)); - /* Only locked once so far. */ - mutex->__data.__count = 1; - } + if (result != 0) + goto out; + + /* Only locked once so far. */ + mutex->__data.__count = 1; break; /* Error checking mutex. */ case PTHREAD_MUTEX_ERRORCHECK_NP: /* Check whether we already hold the mutex. */ - if (mutex->__data.__owner == id) + if (__builtin_expect (mutex->__data.__owner == id, 0)) return EDEADLK; /* FALLTHROUGH */ - default: - /* Correct code cannot set any other type. */ case PTHREAD_MUTEX_TIMED_NP: simple: /* Normal mutex. */ - result = lll_mutex_timedlock (mutex->__data.__lock, abstime); + result = lll_timedlock (mutex->__data.__lock, abstime, + PTHREAD_MUTEX_PSHARED (mutex)); break; case PTHREAD_MUTEX_ADAPTIVE_NP: if (! __is_smp) goto simple; - if (lll_mutex_trylock (mutex->__data.__lock) != 0) + if (lll_trylock (mutex->__data.__lock) != 0) { int cnt = 0; int max_cnt = MIN (MAX_ADAPTIVE_COUNT, @@ -91,7 +94,8 @@ pthread_mutex_timedlock ( { if (cnt++ >= max_cnt) { - result = lll_mutex_timedlock (mutex->__data.__lock, abstime); + result = lll_timedlock (mutex->__data.__lock, abstime, + PTHREAD_MUTEX_PSHARED (mutex)); break; } @@ -99,11 +103,373 @@ pthread_mutex_timedlock ( BUSY_WAIT_NOP; #endif } - while (lll_mutex_trylock (mutex->__data.__lock) != 0); + while (lll_trylock (mutex->__data.__lock) != 0); mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8; } break; + + case PTHREAD_MUTEX_ROBUST_RECURSIVE_NP: + case PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP: + case PTHREAD_MUTEX_ROBUST_NORMAL_NP: + case PTHREAD_MUTEX_ROBUST_ADAPTIVE_NP: + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + &mutex->__data.__list.__next); + + oldval = mutex->__data.__lock; + do + { + again: + if ((oldval & FUTEX_OWNER_DIED) != 0) + { + /* The previous owner died. Try locking the mutex. */ + int newval = id | (oldval & FUTEX_WAITERS); + + newval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + newval, oldval); + if (newval != oldval) + { + oldval = newval; + goto again; + } + + /* We got the mutex. */ + mutex->__data.__count = 1; + /* But it is inconsistent unless marked otherwise. */ + mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; + + ENQUEUE_MUTEX (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Note that we deliberately exit here. If we fall + through to the end of the function __nusers would be + incremented which is not correct because the old + owner has to be discounted. */ + return EOWNERDEAD; + } + + /* Check whether we already hold the mutex. */ + if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0)) + { + int kind = PTHREAD_MUTEX_TYPE (mutex); + if (kind == PTHREAD_MUTEX_ROBUST_ERRORCHECK_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + NULL); + return EDEADLK; + } + + if (kind == PTHREAD_MUTEX_ROBUST_RECURSIVE_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + NULL); + + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + result = lll_robust_timedlock (mutex->__data.__lock, abstime, id, + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)); + + if (__builtin_expect (mutex->__data.__owner + == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) + { + /* This mutex is now not recoverable. */ + mutex->__data.__count = 0; + lll_unlock (mutex->__data.__lock, + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return ENOTRECOVERABLE; + } + + if (result == ETIMEDOUT || result == EINVAL) + goto out; + + oldval = result; + } + while ((oldval & FUTEX_OWNER_DIED) != 0); + + mutex->__data.__count = 1; + ENQUEUE_MUTEX (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + break; + + case PTHREAD_MUTEX_PI_RECURSIVE_NP: + case PTHREAD_MUTEX_PI_ERRORCHECK_NP: + case PTHREAD_MUTEX_PI_NORMAL_NP: + case PTHREAD_MUTEX_PI_ADAPTIVE_NP: + case PTHREAD_MUTEX_PI_ROBUST_RECURSIVE_NP: + case PTHREAD_MUTEX_PI_ROBUST_ERRORCHECK_NP: + case PTHREAD_MUTEX_PI_ROBUST_NORMAL_NP: + case PTHREAD_MUTEX_PI_ROBUST_ADAPTIVE_NP: + { + int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; + int robust = mutex->__data.__kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP; + + if (robust) + /* Note: robust PI futexes are signaled by setting bit 0. */ + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, + (void *) (((uintptr_t) &mutex->__data.__list.__next) + | 1)); + + oldval = mutex->__data.__lock; + + /* Check whether we already hold the mutex. */ + if (__builtin_expect ((oldval & FUTEX_TID_MASK) == id, 0)) + { + if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return EDEADLK; + } + + if (kind == PTHREAD_MUTEX_RECURSIVE_NP) + { + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + id, 0); + + if (oldval != 0) + { + /* The mutex is locked. The kernel will now take care of + everything. The timeout value must be a relative value. + Convert it. */ + int private = (robust + ? PTHREAD_ROBUST_MUTEX_PSHARED (mutex) + : PTHREAD_MUTEX_PSHARED (mutex)); + INTERNAL_SYSCALL_DECL (__err); + + int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, + __lll_private_flag (FUTEX_LOCK_PI, + private), 1, + abstime); + if (INTERNAL_SYSCALL_ERROR_P (e, __err)) + { + if (INTERNAL_SYSCALL_ERRNO (e, __err) == ETIMEDOUT) + return ETIMEDOUT; + + if (INTERNAL_SYSCALL_ERRNO (e, __err) == ESRCH + || INTERNAL_SYSCALL_ERRNO (e, __err) == EDEADLK) + { + assert (INTERNAL_SYSCALL_ERRNO (e, __err) != EDEADLK + || (kind != PTHREAD_MUTEX_ERRORCHECK_NP + && kind != PTHREAD_MUTEX_RECURSIVE_NP)); + /* ESRCH can happen only for non-robust PI mutexes where + the owner of the lock died. */ + assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH + || !robust); + + /* Delay the thread until the timeout is reached. + Then return ETIMEDOUT. */ + struct timespec reltime; + struct timespec now; + + INTERNAL_SYSCALL (clock_gettime, __err, 2, CLOCK_REALTIME, + &now); + reltime.tv_sec = abstime->tv_sec - now.tv_sec; + reltime.tv_nsec = abstime->tv_nsec - now.tv_nsec; + if (reltime.tv_nsec < 0) + { + reltime.tv_nsec += 1000000000; + --reltime.tv_sec; + } + if (reltime.tv_sec >= 0) + while (nanosleep_not_cancel (&reltime, &reltime) != 0) + continue; + + return ETIMEDOUT; + } + + return INTERNAL_SYSCALL_ERRNO (e, __err); + } + + oldval = mutex->__data.__lock; + + assert (robust || (oldval & FUTEX_OWNER_DIED) == 0); + } + + if (__builtin_expect (oldval & FUTEX_OWNER_DIED, 0)) + { + atomic_and (&mutex->__data.__lock, ~FUTEX_OWNER_DIED); + + /* We got the mutex. */ + mutex->__data.__count = 1; + /* But it is inconsistent unless marked otherwise. */ + mutex->__data.__owner = PTHREAD_MUTEX_INCONSISTENT; + + ENQUEUE_MUTEX_PI (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + + /* Note that we deliberately exit here. If we fall + through to the end of the function __nusers would be + incremented which is not correct because the old owner + has to be discounted. */ + return EOWNERDEAD; + } + + if (robust + && __builtin_expect (mutex->__data.__owner + == PTHREAD_MUTEX_NOTRECOVERABLE, 0)) + { + /* This mutex is now not recoverable. */ + mutex->__data.__count = 0; + + INTERNAL_SYSCALL_DECL (__err); + INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, + __lll_private_flag (FUTEX_UNLOCK_PI, + PTHREAD_ROBUST_MUTEX_PSHARED (mutex)), + 0, 0); + + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + return ENOTRECOVERABLE; + } + + mutex->__data.__count = 1; + if (robust) + { + ENQUEUE_MUTEX_PI (mutex); + THREAD_SETMEM (THREAD_SELF, robust_head.list_op_pending, NULL); + } + } + break; + + case PTHREAD_MUTEX_PP_RECURSIVE_NP: + case PTHREAD_MUTEX_PP_ERRORCHECK_NP: + case PTHREAD_MUTEX_PP_NORMAL_NP: + case PTHREAD_MUTEX_PP_ADAPTIVE_NP: + { + int kind = mutex->__data.__kind & PTHREAD_MUTEX_KIND_MASK_NP; + + oldval = mutex->__data.__lock; + + /* Check whether we already hold the mutex. */ + if (mutex->__data.__owner == id) + { + if (kind == PTHREAD_MUTEX_ERRORCHECK_NP) + return EDEADLK; + + if (kind == PTHREAD_MUTEX_RECURSIVE_NP) + { + /* Just bump the counter. */ + if (__builtin_expect (mutex->__data.__count + 1 == 0, 0)) + /* Overflow of the counter. */ + return EAGAIN; + + ++mutex->__data.__count; + + return 0; + } + } + + int oldprio = -1, ceilval; + do + { + int ceiling = (oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) + >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + + if (__pthread_current_priority () > ceiling) + { + result = EINVAL; + failpp: + if (oldprio != -1) + __pthread_tpp_change_priority (oldprio, -1); + return result; + } + + result = __pthread_tpp_change_priority (oldprio, ceiling); + if (result) + return result; + + ceilval = ceiling << PTHREAD_MUTEX_PRIO_CEILING_SHIFT; + oldprio = ceiling; + + oldval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 1, ceilval); + + if (oldval == ceilval) + break; + + do + { + oldval + = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, + ceilval | 1); + + if ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval) + break; + + if (oldval != ceilval) + { + /* Reject invalid timeouts. */ + if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) + { + result = EINVAL; + goto failpp; + } + + struct timeval tv; + struct timespec rt; + + /* Get the current time. */ + (void) gettimeofday (&tv, NULL); + + /* Compute relative timeout. */ + rt.tv_sec = abstime->tv_sec - tv.tv_sec; + rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; + if (rt.tv_nsec < 0) + { + rt.tv_nsec += 1000000000; + --rt.tv_sec; + } + + /* Already timed out? */ + if (rt.tv_sec < 0) + { + result = ETIMEDOUT; + goto failpp; + } + + lll_futex_timed_wait (&mutex->__data.__lock, + ceilval | 2, &rt, + PTHREAD_MUTEX_PSHARED (mutex)); + } + } + while (atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + ceilval | 2, ceilval) + != ceilval); + } + while ((oldval & PTHREAD_MUTEX_PRIO_CEILING_MASK) != ceilval); + + assert (mutex->__data.__owner == 0); + mutex->__data.__count = 1; + } + break; + + default: + /* Correct code cannot set any other type. */ + return EINVAL; } if (result == 0) |