1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * Copyright (c) 2015, Linaro Limited 4 */ 5 #ifndef KERNEL_WAIT_QUEUE_H 6 #define KERNEL_WAIT_QUEUE_H 7 8 #include <types_ext.h> 9 #include <sys/queue.h> 10 11 struct wait_queue_elem; 12 SLIST_HEAD(wait_queue, wait_queue_elem); 13 14 #define WAIT_QUEUE_INITIALIZER { .slh_first = NULL } 15 16 struct condvar; 17 struct wait_queue_elem { 18 short handle; 19 bool done; 20 bool wait_read; 21 struct condvar *cv; 22 SLIST_ENTRY(wait_queue_elem) link; 23 }; 24 25 /* 26 * Initializes a wait queue 27 */ 28 void wq_init(struct wait_queue *wq); 29 30 /* 31 * Initializes a wait queue element and adds it to the wait queue. This 32 * function is supposed to be called before the lock that protects the 33 * resource we need to wait for is released. 34 * 35 * One call to this function must be followed by one call to wq_wait_final() 36 * on the same wait queue element. 37 */ 38 void wq_wait_init_condvar(struct wait_queue *wq, struct wait_queue_elem *wqe, 39 struct condvar *cv, bool wait_read); 40 41 static inline void wq_wait_init(struct wait_queue *wq, 42 struct wait_queue_elem *wqe, bool wait_read) 43 { 44 wq_wait_init_condvar(wq, wqe, NULL, wait_read); 45 } 46 47 /* Waits for the wait queue element to the awakened. */ 48 void wq_wait_final(struct wait_queue *wq, struct wait_queue_elem *wqe, 49 const void *sync_obj, const char *fname, int lineno); 50 51 /* Wakes up the first wait queue element in the wait queue, if there is one */ 52 void wq_wake_next(struct wait_queue *wq, const void *sync_obj, 53 const char *fname, int lineno); 54 55 /* Returns true if the wait queue doesn't contain any elements */ 56 bool wq_is_empty(struct wait_queue *wq); 57 58 void wq_promote_condvar(struct wait_queue *wq, struct condvar *cv, 59 bool only_one, const void *sync_obj, const char *fname, 60 int lineno); 61 bool wq_have_condvar(struct wait_queue *wq, struct condvar *cv); 62 63 #endif /*KERNEL_WAIT_QUEUE_H*/ 64 65