kern: src/mutex.c annotate

kern

implementing ata read/write

author	John Tsiombikas <nuclear@member.fsf.org>
date	Wed, 07 Dec 2011 14:03:11 +0200
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rev	line source
nuclear@86	1 #include <assert.h>
nuclear@86	2 #include "mutex.h"
nuclear@86	3 #include "sched.h"
nuclear@86	4 #include "intr.h"
nuclear@86	5
nuclear@86	6 void mutex_lock(mutex_t *m)
nuclear@86	7 {
nuclear@86	8 int istate = get_intr_state();
nuclear@86	9 disable_intr();
nuclear@86	10
nuclear@86	11 /* sleep while the mutex is held */
nuclear@86	12 while(*m > 0) {
nuclear@86	13 wait(m);
nuclear@86	14 }
nuclear@86	15 /* then grab it... */
nuclear@86	16 (*m)++;
nuclear@86	17
nuclear@86	18 set_intr_state(istate);
nuclear@86	19 }
nuclear@86	20
nuclear@86	21 void mutex_unlock(mutex_t *m)
nuclear@86	22 {
nuclear@86	23 int istate = get_intr_state();
nuclear@86	24 disable_intr();
nuclear@86	25
nuclear@86	26 assert(*m);
nuclear@86	27 /* release the mutex and wakeup everyone waiting on it */
nuclear@86	28 (*m)--;
nuclear@86	29 wakeup(m);
nuclear@86	30
nuclear@86	31 set_intr_state(istate);
nuclear@86	32 }
nuclear@86	33
nuclear@86	34 int mutex_trylock(mutex_t *m)
nuclear@86	35 {
nuclear@86	36 int res = -1, istate = get_intr_state();
nuclear@86	37 disable_intr();
nuclear@86	38
nuclear@86	39 if(*m == 0) {
nuclear@86	40 (*m)++;
nuclear@86	41 res = 0;
nuclear@86	42 }
nuclear@86	43 set_intr_state(istate);
nuclear@86	44 return res;
nuclear@86	45 }