1 /* Linuxthreads - a simple clone()-based implementation of Posix */ 2 /* threads for Linux. */ 3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ 4 /* */ 5 /* This program is free software; you can redistribute it and/or */ 6 /* modify it under the terms of the GNU Library General Public License */ 7 /* as published by the Free Software Foundation; either version 2 */ 8 /* of the License, or (at your option) any later version. */ 9 /* */ 10 /* This program is distributed in the hope that it will be useful, */ 11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ 12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ 13 /* GNU Library General Public License for more details. */ 14 15 /* Waiting queues */ 16 17 /* Waiting queues are represented by lists of thread descriptors 18 linked through their p_nextwaiting field. The lists are kept 19 sorted by decreasing priority, and then decreasing waiting time. */ 20 enqueue(pthread_descr * q,pthread_descr th)21static __inline__ void enqueue(pthread_descr * q, pthread_descr th) 22 { 23 int prio = th->p_priority; 24 ASSERT(th->p_nextwaiting == NULL); 25 for (; *q != NULL; q = &((*q)->p_nextwaiting)) { 26 if (prio > (*q)->p_priority) { 27 th->p_nextwaiting = *q; 28 *q = th; 29 return; 30 } 31 } 32 *q = th; 33 } 34 dequeue(pthread_descr * q)35static __inline__ pthread_descr dequeue(pthread_descr * q) 36 { 37 pthread_descr th; 38 th = *q; 39 if (th != NULL) { 40 *q = th->p_nextwaiting; 41 th->p_nextwaiting = NULL; 42 } 43 return th; 44 } 45 remove_from_queue(pthread_descr * q,pthread_descr th)46static __inline__ int remove_from_queue(pthread_descr * q, pthread_descr th) 47 { 48 for (; *q != NULL; q = &((*q)->p_nextwaiting)) { 49 if (*q == th) { 50 *q = th->p_nextwaiting; 51 th->p_nextwaiting = NULL; 52 return 1; 53 } 54 } 55 return 0; 56 } 57 queue_is_empty(pthread_descr * q)58static __inline__ int queue_is_empty(pthread_descr * q) 59 { 60 return *q == NULL; 61 } 62