diff options
Diffstat (limited to 'nptl/pthread_mutex_lock.c')
| -rw-r--r-- | nptl/pthread_mutex_lock.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/nptl/pthread_mutex_lock.c b/nptl/pthread_mutex_lock.c index 06eef49c71..5345766883 100644 --- a/nptl/pthread_mutex_lock.c +++ b/nptl/pthread_mutex_lock.c @@ -20,6 +20,7 @@ #include <assert.h> #include <errno.h> #include <stdlib.h> +#include <unistd.h> #include "pthreadP.h" #include <lowlevellock.h> @@ -205,6 +206,134 @@ __pthread_mutex_lock (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; + } + } + + int newval = id; +#ifdef NO_INCR + newval |= FUTEX_WAITERS; +#endif + oldval = atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, + newval, 0); + + if (oldval != 0) + { + /* The mutex is locked. The kernel will now take care of + everything. */ + INTERNAL_SYSCALL_DECL (__err); + int e = INTERNAL_SYSCALL (futex, __err, 4, &mutex->__data.__lock, + FUTEX_LOCK_PI, 1, 0); + + if (INTERNAL_SYSCALL_ERROR_P (e, __err) + && (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 indefinitely. */ + while (1) + __pause_nocancel (); + } + + 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. If we are not supposed to + increment __nusers we actually have to decrement it here. */ +#ifdef NO_INCR + --mutex->__data.__nusers; +#endif + + 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, + FUTEX_UNLOCK_PI, 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; + default: /* Correct code cannot set any other type. */ return EINVAL; |