1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
|
/* Synchronous wrapper for memory_object_lock_request
Copyright (C) 1993, 1994 Free Software Foundation
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Request a lock from the kernel. Parameters are as for
memory_object_lock_request. If SYNC is set, then wait for
the operation to fully complete before returning. */
void
lock_object (struct pager *p,
vm_offset_t offset,
vm_size_t size,
int should_return,
int should_flush,
vm_prot_t lock_value,
int sync)
{
struct lock_request *lr = 0;
mutex_lock (&p->interlock);
if (p->pager_state != NORMAL)
{
mutex_unlock (&p->interlock);
return;
}
if (sync)
{
for (lr = p->lock_requests; lr; lr = lr->next)
if (lr->start == offset && lr->end == offset + size)
{
lr->locks_pending++;
lr->threads_waiting++;
break;
}
if (!lr)
{
lr = malloc (sizeof (struct lock_request));
lr->start = offset;
lr->end = offset + size;
lr->pending_writes = 0;
lr->locks_pending = 1;
lr->threads_waiting = 1;
lr->next = p->lock_requests;
if (lr->next)
lr->next->prevp = &lr->next;
lr->prevp = &p->lock_requests;
p->lock_requests = lr;
}
}
memory_object_lock_request (p->memobjcntl, offset, size, should_return,
should_flush, lock_value,
sync ? p->port.port : MACH_PORT_NULL);
if (sync)
{
while (lr->locks_pending || lr->pending_writes)
condition_wait (&p->wakeup, &p->interlock);
if (!--lr->threads_waiting)
{
*lr->prevp = lr->next;
free (lr);
}
}
mutex_unlock (&p->interlock);
}
|
