root / aio-win32.c @ f2e5dca4
History | View | Annotate | Download (5.5 kB)
1 |
/*
|
---|---|
2 |
* QEMU aio implementation
|
3 |
*
|
4 |
* Copyright IBM Corp., 2008
|
5 |
* Copyright Red Hat Inc., 2012
|
6 |
*
|
7 |
* Authors:
|
8 |
* Anthony Liguori <aliguori@us.ibm.com>
|
9 |
* Paolo Bonzini <pbonzini@redhat.com>
|
10 |
*
|
11 |
* This work is licensed under the terms of the GNU GPL, version 2. See
|
12 |
* the COPYING file in the top-level directory.
|
13 |
*
|
14 |
* Contributions after 2012-01-13 are licensed under the terms of the
|
15 |
* GNU GPL, version 2 or (at your option) any later version.
|
16 |
*/
|
17 |
|
18 |
#include "qemu-common.h" |
19 |
#include "block/block.h" |
20 |
#include "qemu/queue.h" |
21 |
#include "qemu/sockets.h" |
22 |
|
23 |
struct AioHandler {
|
24 |
EventNotifier *e; |
25 |
EventNotifierHandler *io_notify; |
26 |
GPollFD pfd; |
27 |
int deleted;
|
28 |
QLIST_ENTRY(AioHandler) node; |
29 |
}; |
30 |
|
31 |
void aio_set_event_notifier(AioContext *ctx,
|
32 |
EventNotifier *e, |
33 |
EventNotifierHandler *io_notify) |
34 |
{ |
35 |
AioHandler *node; |
36 |
|
37 |
QLIST_FOREACH(node, &ctx->aio_handlers, node) { |
38 |
if (node->e == e && !node->deleted) {
|
39 |
break;
|
40 |
} |
41 |
} |
42 |
|
43 |
/* Are we deleting the fd handler? */
|
44 |
if (!io_notify) {
|
45 |
if (node) {
|
46 |
g_source_remove_poll(&ctx->source, &node->pfd); |
47 |
|
48 |
/* If the lock is held, just mark the node as deleted */
|
49 |
if (ctx->walking_handlers) {
|
50 |
node->deleted = 1;
|
51 |
node->pfd.revents = 0;
|
52 |
} else {
|
53 |
/* Otherwise, delete it for real. We can't just mark it as
|
54 |
* deleted because deleted nodes are only cleaned up after
|
55 |
* releasing the walking_handlers lock.
|
56 |
*/
|
57 |
QLIST_REMOVE(node, node); |
58 |
g_free(node); |
59 |
} |
60 |
} |
61 |
} else {
|
62 |
if (node == NULL) { |
63 |
/* Alloc and insert if it's not already there */
|
64 |
node = g_malloc0(sizeof(AioHandler));
|
65 |
node->e = e; |
66 |
node->pfd.fd = (uintptr_t)event_notifier_get_handle(e); |
67 |
node->pfd.events = G_IO_IN; |
68 |
QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node); |
69 |
|
70 |
g_source_add_poll(&ctx->source, &node->pfd); |
71 |
} |
72 |
/* Update handler with latest information */
|
73 |
node->io_notify = io_notify; |
74 |
} |
75 |
|
76 |
aio_notify(ctx); |
77 |
} |
78 |
|
79 |
bool aio_pending(AioContext *ctx)
|
80 |
{ |
81 |
AioHandler *node; |
82 |
|
83 |
QLIST_FOREACH(node, &ctx->aio_handlers, node) { |
84 |
if (node->pfd.revents && node->io_notify) {
|
85 |
return true; |
86 |
} |
87 |
} |
88 |
|
89 |
return false; |
90 |
} |
91 |
|
92 |
bool aio_poll(AioContext *ctx, bool blocking) |
93 |
{ |
94 |
AioHandler *node; |
95 |
HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
|
96 |
bool progress;
|
97 |
int count;
|
98 |
|
99 |
progress = false;
|
100 |
|
101 |
/*
|
102 |
* If there are callbacks left that have been queued, we need to call then.
|
103 |
* Do not call select in this case, because it is possible that the caller
|
104 |
* does not need a complete flush (as is the case for qemu_aio_wait loops).
|
105 |
*/
|
106 |
if (aio_bh_poll(ctx)) {
|
107 |
blocking = false;
|
108 |
progress = true;
|
109 |
} |
110 |
|
111 |
/*
|
112 |
* Then dispatch any pending callbacks from the GSource.
|
113 |
*
|
114 |
* We have to walk very carefully in case qemu_aio_set_fd_handler is
|
115 |
* called while we're walking.
|
116 |
*/
|
117 |
node = QLIST_FIRST(&ctx->aio_handlers); |
118 |
while (node) {
|
119 |
AioHandler *tmp; |
120 |
|
121 |
ctx->walking_handlers++; |
122 |
|
123 |
if (node->pfd.revents && node->io_notify) {
|
124 |
node->pfd.revents = 0;
|
125 |
node->io_notify(node->e); |
126 |
|
127 |
/* aio_notify() does not count as progress */
|
128 |
if (node->opaque != &ctx->notifier) {
|
129 |
progress = true;
|
130 |
} |
131 |
} |
132 |
|
133 |
tmp = node; |
134 |
node = QLIST_NEXT(node, node); |
135 |
|
136 |
ctx->walking_handlers--; |
137 |
|
138 |
if (!ctx->walking_handlers && tmp->deleted) {
|
139 |
QLIST_REMOVE(tmp, node); |
140 |
g_free(tmp); |
141 |
} |
142 |
} |
143 |
|
144 |
if (progress && !blocking) {
|
145 |
return true; |
146 |
} |
147 |
|
148 |
ctx->walking_handlers++; |
149 |
|
150 |
/* fill fd sets */
|
151 |
count = 0;
|
152 |
QLIST_FOREACH(node, &ctx->aio_handlers, node) { |
153 |
if (!node->deleted && node->io_notify) {
|
154 |
events[count++] = event_notifier_get_handle(node->e); |
155 |
} |
156 |
} |
157 |
|
158 |
ctx->walking_handlers--; |
159 |
|
160 |
/* early return if we only have the aio_notify() fd */
|
161 |
if (count == 1) { |
162 |
return progress;
|
163 |
} |
164 |
|
165 |
/* wait until next event */
|
166 |
while (count > 0) { |
167 |
int timeout = blocking ? INFINITE : 0; |
168 |
int ret = WaitForMultipleObjects(count, events, FALSE, timeout);
|
169 |
|
170 |
/* if we have any signaled events, dispatch event */
|
171 |
if ((DWORD) (ret - WAIT_OBJECT_0) >= count) {
|
172 |
break;
|
173 |
} |
174 |
|
175 |
blocking = false;
|
176 |
|
177 |
/* we have to walk very carefully in case
|
178 |
* qemu_aio_set_fd_handler is called while we're walking */
|
179 |
node = QLIST_FIRST(&ctx->aio_handlers); |
180 |
while (node) {
|
181 |
AioHandler *tmp; |
182 |
|
183 |
ctx->walking_handlers++; |
184 |
|
185 |
if (!node->deleted &&
|
186 |
event_notifier_get_handle(node->e) == events[ret - WAIT_OBJECT_0] && |
187 |
node->io_notify) { |
188 |
node->io_notify(node->e); |
189 |
|
190 |
/* aio_notify() does not count as progress */
|
191 |
if (node->opaque != &ctx->notifier) {
|
192 |
progress = true;
|
193 |
} |
194 |
} |
195 |
|
196 |
tmp = node; |
197 |
node = QLIST_NEXT(node, node); |
198 |
|
199 |
ctx->walking_handlers--; |
200 |
|
201 |
if (!ctx->walking_handlers && tmp->deleted) {
|
202 |
QLIST_REMOVE(tmp, node); |
203 |
g_free(tmp); |
204 |
} |
205 |
} |
206 |
|
207 |
/* Try again, but only call each handler once. */
|
208 |
events[ret - WAIT_OBJECT_0] = events[--count]; |
209 |
} |
210 |
|
211 |
return progress;
|
212 |
} |