kern
view src/mutex.c @ 86:379332fc1667
implementing ata read/write
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Wed, 07 Dec 2011 14:03:11 +0200 |
| parents | |
| children |
line source
1 #include <assert.h>
2 #include "mutex.h"
3 #include "sched.h"
4 #include "intr.h"
6 void mutex_lock(mutex_t *m)
7 {
8 int istate = get_intr_state();
9 disable_intr();
11 /* sleep while the mutex is held */
12 while(*m > 0) {
13 wait(m);
14 }
15 /* then grab it... */
16 (*m)++;
18 set_intr_state(istate);
19 }
21 void mutex_unlock(mutex_t *m)
22 {
23 int istate = get_intr_state();
24 disable_intr();
26 assert(*m);
27 /* release the mutex and wakeup everyone waiting on it */
28 (*m)--;
29 wakeup(m);
31 set_intr_state(istate);
32 }
34 int mutex_trylock(mutex_t *m)
35 {
36 int res = -1, istate = get_intr_state();
37 disable_intr();
39 if(*m == 0) {
40 (*m)++;
41 res = 0;
42 }
43 set_intr_state(istate);
44 return res;
45 }