ahci: Fix FIS decomposition
[qemu.git] / aio-win32.c
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 IOHandler *io_read;
26 IOHandler *io_write;
27 EventNotifierHandler *io_notify;
28 GPollFD pfd;
29 int deleted;
30 void *opaque;
31 QLIST_ENTRY(AioHandler) node;
32 };
33
34 void aio_set_fd_handler(AioContext *ctx,
35 int fd,
36 IOHandler *io_read,
37 IOHandler *io_write,
38 void *opaque)
39 {
40 /* fd is a SOCKET in our case */
41 AioHandler *node;
42
43 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
44 if (node->pfd.fd == fd && !node->deleted) {
45 break;
46 }
47 }
48
49 /* Are we deleting the fd handler? */
50 if (!io_read && !io_write) {
51 if (node) {
52 /* If the lock is held, just mark the node as deleted */
53 if (ctx->walking_handlers) {
54 node->deleted = 1;
55 node->pfd.revents = 0;
56 } else {
57 /* Otherwise, delete it for real. We can't just mark it as
58 * deleted because deleted nodes are only cleaned up after
59 * releasing the walking_handlers lock.
60 */
61 QLIST_REMOVE(node, node);
62 g_free(node);
63 }
64 }
65 } else {
66 HANDLE event;
67
68 if (node == NULL) {
69 /* Alloc and insert if it's not already there */
70 node = g_malloc0(sizeof(AioHandler));
71 node->pfd.fd = fd;
72 QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node);
73 }
74
75 node->pfd.events = 0;
76 if (node->io_read) {
77 node->pfd.events |= G_IO_IN;
78 }
79 if (node->io_write) {
80 node->pfd.events |= G_IO_OUT;
81 }
82
83 node->e = &ctx->notifier;
84
85 /* Update handler with latest information */
86 node->opaque = opaque;
87 node->io_read = io_read;
88 node->io_write = io_write;
89
90 event = event_notifier_get_handle(&ctx->notifier);
91 WSAEventSelect(node->pfd.fd, event,
92 FD_READ | FD_ACCEPT | FD_CLOSE |
93 FD_CONNECT | FD_WRITE | FD_OOB);
94 }
95
96 aio_notify(ctx);
97 }
98
99 void aio_set_event_notifier(AioContext *ctx,
100 EventNotifier *e,
101 EventNotifierHandler *io_notify)
102 {
103 AioHandler *node;
104
105 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
106 if (node->e == e && !node->deleted) {
107 break;
108 }
109 }
110
111 /* Are we deleting the fd handler? */
112 if (!io_notify) {
113 if (node) {
114 g_source_remove_poll(&ctx->source, &node->pfd);
115
116 /* If the lock is held, just mark the node as deleted */
117 if (ctx->walking_handlers) {
118 node->deleted = 1;
119 node->pfd.revents = 0;
120 } else {
121 /* Otherwise, delete it for real. We can't just mark it as
122 * deleted because deleted nodes are only cleaned up after
123 * releasing the walking_handlers lock.
124 */
125 QLIST_REMOVE(node, node);
126 g_free(node);
127 }
128 }
129 } else {
130 if (node == NULL) {
131 /* Alloc and insert if it's not already there */
132 node = g_malloc0(sizeof(AioHandler));
133 node->e = e;
134 node->pfd.fd = (uintptr_t)event_notifier_get_handle(e);
135 node->pfd.events = G_IO_IN;
136 QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node);
137
138 g_source_add_poll(&ctx->source, &node->pfd);
139 }
140 /* Update handler with latest information */
141 node->io_notify = io_notify;
142 }
143
144 aio_notify(ctx);
145 }
146
147 bool aio_prepare(AioContext *ctx)
148 {
149 static struct timeval tv0;
150 AioHandler *node;
151 bool have_select_revents = false;
152 fd_set rfds, wfds;
153
154 /* fill fd sets */
155 FD_ZERO(&rfds);
156 FD_ZERO(&wfds);
157 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
158 if (node->io_read) {
159 FD_SET ((SOCKET)node->pfd.fd, &rfds);
160 }
161 if (node->io_write) {
162 FD_SET ((SOCKET)node->pfd.fd, &wfds);
163 }
164 }
165
166 if (select(0, &rfds, &wfds, NULL, &tv0) > 0) {
167 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
168 node->pfd.revents = 0;
169 if (FD_ISSET(node->pfd.fd, &rfds)) {
170 node->pfd.revents |= G_IO_IN;
171 have_select_revents = true;
172 }
173
174 if (FD_ISSET(node->pfd.fd, &wfds)) {
175 node->pfd.revents |= G_IO_OUT;
176 have_select_revents = true;
177 }
178 }
179 }
180
181 return have_select_revents;
182 }
183
184 bool aio_pending(AioContext *ctx)
185 {
186 AioHandler *node;
187
188 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
189 if (node->pfd.revents && node->io_notify) {
190 return true;
191 }
192
193 if ((node->pfd.revents & G_IO_IN) && node->io_read) {
194 return true;
195 }
196 if ((node->pfd.revents & G_IO_OUT) && node->io_write) {
197 return true;
198 }
199 }
200
201 return false;
202 }
203
204 static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
205 {
206 AioHandler *node;
207 bool progress = false;
208
209 /*
210 * We have to walk very carefully in case aio_set_fd_handler is
211 * called while we're walking.
212 */
213 node = QLIST_FIRST(&ctx->aio_handlers);
214 while (node) {
215 AioHandler *tmp;
216 int revents = node->pfd.revents;
217
218 ctx->walking_handlers++;
219
220 if (!node->deleted &&
221 (revents || event_notifier_get_handle(node->e) == event) &&
222 node->io_notify) {
223 node->pfd.revents = 0;
224 node->io_notify(node->e);
225
226 /* aio_notify() does not count as progress */
227 if (node->e != &ctx->notifier) {
228 progress = true;
229 }
230 }
231
232 if (!node->deleted &&
233 (node->io_read || node->io_write)) {
234 node->pfd.revents = 0;
235 if ((revents & G_IO_IN) && node->io_read) {
236 node->io_read(node->opaque);
237 progress = true;
238 }
239 if ((revents & G_IO_OUT) && node->io_write) {
240 node->io_write(node->opaque);
241 progress = true;
242 }
243
244 /* if the next select() will return an event, we have progressed */
245 if (event == event_notifier_get_handle(&ctx->notifier)) {
246 WSANETWORKEVENTS ev;
247 WSAEnumNetworkEvents(node->pfd.fd, event, &ev);
248 if (ev.lNetworkEvents) {
249 progress = true;
250 }
251 }
252 }
253
254 tmp = node;
255 node = QLIST_NEXT(node, node);
256
257 ctx->walking_handlers--;
258
259 if (!ctx->walking_handlers && tmp->deleted) {
260 QLIST_REMOVE(tmp, node);
261 g_free(tmp);
262 }
263 }
264
265 return progress;
266 }
267
268 bool aio_dispatch(AioContext *ctx)
269 {
270 bool progress;
271
272 progress = aio_bh_poll(ctx);
273 progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
274 progress |= timerlistgroup_run_timers(&ctx->tlg);
275 return progress;
276 }
277
278 bool aio_poll(AioContext *ctx, bool blocking)
279 {
280 AioHandler *node;
281 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
282 bool was_dispatching, progress, have_select_revents, first;
283 int count;
284 int timeout;
285
286 have_select_revents = aio_prepare(ctx);
287 if (have_select_revents) {
288 blocking = false;
289 }
290
291 was_dispatching = ctx->dispatching;
292 progress = false;
293
294 /* aio_notify can avoid the expensive event_notifier_set if
295 * everything (file descriptors, bottom halves, timers) will
296 * be re-evaluated before the next blocking poll(). This is
297 * already true when aio_poll is called with blocking == false;
298 * if blocking == true, it is only true after poll() returns.
299 *
300 * If we're in a nested event loop, ctx->dispatching might be true.
301 * In that case we can restore it just before returning, but we
302 * have to clear it now.
303 */
304 aio_set_dispatching(ctx, !blocking);
305
306 ctx->walking_handlers++;
307
308 /* fill fd sets */
309 count = 0;
310 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
311 if (!node->deleted && node->io_notify) {
312 events[count++] = event_notifier_get_handle(node->e);
313 }
314 }
315
316 ctx->walking_handlers--;
317 first = true;
318
319 /* wait until next event */
320 while (count > 0) {
321 HANDLE event;
322 int ret;
323
324 timeout = blocking
325 ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
326 ret = WaitForMultipleObjects(count, events, FALSE, timeout);
327 aio_set_dispatching(ctx, true);
328
329 if (first && aio_bh_poll(ctx)) {
330 progress = true;
331 }
332 first = false;
333
334 /* if we have any signaled events, dispatch event */
335 event = NULL;
336 if ((DWORD) (ret - WAIT_OBJECT_0) < count) {
337 event = events[ret - WAIT_OBJECT_0];
338 events[ret - WAIT_OBJECT_0] = events[--count];
339 } else if (!have_select_revents) {
340 break;
341 }
342
343 have_select_revents = false;
344 blocking = false;
345
346 progress |= aio_dispatch_handlers(ctx, event);
347 }
348
349 progress |= timerlistgroup_run_timers(&ctx->tlg);
350
351 aio_set_dispatching(ctx, was_dispatching);
352 return progress;
353 }