xref: /xv6-public/sleeplock.c (revision 0b86d037) 
1 // Sleeping locks
2 
3 #include "types.h"
4 #include "defs.h"
5 #include "param.h"
6 #include "x86.h"
7 #include "memlayout.h"
8 #include "mmu.h"
9 #include "proc.h"
10 #include "spinlock.h"
11 #include "sleeplock.h"
12 
13 void
initsleeplock(struct sleeplock * lk,char * name)14 initsleeplock(struct sleeplock *lk, char *name)
15 {
16   initlock(&lk->lk, "sleep lock");
17   lk->name = name;
18   lk->locked = 0;
19   lk->pid = 0;
20 }
21 
22 void
acquiresleep(struct sleeplock * lk)23 acquiresleep(struct sleeplock *lk)
24 {
25   acquire(&lk->lk);
26   while (lk->locked) {
27     sleep(lk, &lk->lk);
28   }
29   lk->locked = 1;
30   lk->pid = myproc()->pid;
31   release(&lk->lk);
32 }
33 
34 void
releasesleep(struct sleeplock * lk)35 releasesleep(struct sleeplock *lk)
36 {
37   acquire(&lk->lk);
38   lk->locked = 0;
39   lk->pid = 0;
40   wakeup(lk);
41   release(&lk->lk);
42 }
43 
44 int
holdingsleep(struct sleeplock * lk)45 holdingsleep(struct sleeplock *lk)
46 {
47   int r;
48 
49   acquire(&lk->lk);
50   r = lk->locked && (lk->pid == myproc()->pid);
51   release(&lk->lk);
52   return r;
53 }
54 
55 
56 
57