sys/src/lib9p/queue.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <thread.h>
   4 #include <fcall.h>
   5 #include <9p.h>
   6
   7 static void
   8 _reqqueueproc(void *v)
   9 {
  10         Reqqueue *q;
  11         Req *r;
  12         void (*f)(Req *);
  13         int fd;
  14         char *buf;
  15
  16         q = v;
  17         rfork(RFNOTEG);
  18
  19         buf = smprint("/proc/%d/ctl", getpid());
  20         fd = open(buf, OWRITE);
  21         free(buf);
  22
  23         for(;;){
  24                 qlock(q);
  25                 q->flush = 0;
  26                 if(fd >= 0)
  27                         write(fd, "nointerrupt", 11);
  28                 q->cur = nil;
  29                 while(q->next == q)
  30                         rsleep(q);
  31                 r = (Req*)(((char*)q->next) - ((char*)&((Req*)0)->qu));
  32                 r->qu.next->prev = r->qu.prev;
  33                 r->qu.prev->next = r->qu.next;
  34                 f = r->qu.f;
  35                 memset(&r->qu, 0, sizeof(r->qu));
  36                 q->cur = r;
  37                 qunlock(q);
  38                 if(f == nil)
  39                         break;
  40                 f(r);
  41         }
  42
  43         free(r);
  44         free(q);
  45         threadexits(nil);
  46 }
  47
  48 Reqqueue *
  49 reqqueuecreate(void)
  50 {
  51         Reqqueue *q;
  52
  53         q = emalloc9p(sizeof(*q));
  54         memset(q, 0, sizeof(*q));
  55         q->l = q;
  56         q->next = q->prev = q;
  57         q->pid = proccreate(_reqqueueproc, q, mainstacksize);
  58         return q;
  59 }
  60
  61 void
  62 reqqueuepush(Reqqueue *q, Req *r, void (*f)(Req *))
  63 {
  64         qlock(q);
  65         r->qu.f = f;
  66         r->qu.next = q;
  67         r->qu.prev = q->prev;
  68         q->prev->next = &r->qu;
  69         q->prev = &r->qu;
  70         rwakeup(q);
  71         qunlock(q);
  72 }
  73
  74 void
  75 reqqueueflush(Reqqueue *q, Req *r)
  76 {
  77         qlock(q);
  78         if(q->cur == r){
  79                 threadint(q->pid);
  80                 q->flush++;
  81                 qunlock(q);
  82         }else{
  83                 if(r->qu.next != nil){
  84                         r->qu.next->prev = r->qu.prev;
  85                         r->qu.prev->next = r->qu.next;
  86                 }
  87                 memset(&r->qu, 0, sizeof(r->qu));
  88                 qunlock(q);
  89                 respond(r, "interrupted");
  90         }
  91 }
  92
  93 void
  94 reqqueuefree(Reqqueue *q)
  95 {
  96         Req *r;
  97
  98         if(q == nil)
  99                 return;
 100         r = emalloc9p(sizeof(Req));
 101         reqqueuepush(q, r, nil);
 102 }