qemu-log: Rename CPULogItem, cpu_log_items to QEMULogItem, qemu_log_items
[qemu/pbrook.git] / aio-posix.c
blobfe4dbb4523e6fcc8272ff5f19c2ef07c9160fd25
1 /*
2 * QEMU aio implementation
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
12 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
16 #include "qemu-common.h"
17 #include "block/block.h"
18 #include "qemu/queue.h"
19 #include "qemu/sockets.h"
21 struct AioHandler
23 GPollFD pfd;
24 IOHandler *io_read;
25 IOHandler *io_write;
26 AioFlushHandler *io_flush;
27 int deleted;
28 void *opaque;
29 QLIST_ENTRY(AioHandler) node;
32 static AioHandler *find_aio_handler(AioContext *ctx, int fd)
34 AioHandler *node;
36 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
37 if (node->pfd.fd == fd)
38 if (!node->deleted)
39 return node;
42 return NULL;
45 void aio_set_fd_handler(AioContext *ctx,
46 int fd,
47 IOHandler *io_read,
48 IOHandler *io_write,
49 AioFlushHandler *io_flush,
50 void *opaque)
52 AioHandler *node;
54 node = find_aio_handler(ctx, fd);
56 /* Are we deleting the fd handler? */
57 if (!io_read && !io_write) {
58 if (node) {
59 g_source_remove_poll(&ctx->source, &node->pfd);
61 /* If the lock is held, just mark the node as deleted */
62 if (ctx->walking_handlers) {
63 node->deleted = 1;
64 node->pfd.revents = 0;
65 } else {
66 /* Otherwise, delete it for real. We can't just mark it as
67 * deleted because deleted nodes are only cleaned up after
68 * releasing the walking_handlers lock.
70 QLIST_REMOVE(node, node);
71 g_free(node);
74 } else {
75 if (node == NULL) {
76 /* Alloc and insert if it's not already there */
77 node = g_malloc0(sizeof(AioHandler));
78 node->pfd.fd = fd;
79 QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node);
81 g_source_add_poll(&ctx->source, &node->pfd);
83 /* Update handler with latest information */
84 node->io_read = io_read;
85 node->io_write = io_write;
86 node->io_flush = io_flush;
87 node->opaque = opaque;
89 node->pfd.events = (io_read ? G_IO_IN | G_IO_HUP : 0);
90 node->pfd.events |= (io_write ? G_IO_OUT : 0);
93 aio_notify(ctx);
96 void aio_set_event_notifier(AioContext *ctx,
97 EventNotifier *notifier,
98 EventNotifierHandler *io_read,
99 AioFlushEventNotifierHandler *io_flush)
101 aio_set_fd_handler(ctx, event_notifier_get_fd(notifier),
102 (IOHandler *)io_read, NULL,
103 (AioFlushHandler *)io_flush, notifier);
106 bool aio_pending(AioContext *ctx)
108 AioHandler *node;
110 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
111 int revents;
114 * FIXME: right now we cannot get G_IO_HUP and G_IO_ERR because
115 * main-loop.c is still select based (due to the slirp legacy).
116 * If main-loop.c ever switches to poll, G_IO_ERR should be
117 * tested too. Dispatching G_IO_ERR to both handlers should be
118 * okay, since handlers need to be ready for spurious wakeups.
120 revents = node->pfd.revents & node->pfd.events;
121 if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read) {
122 return true;
124 if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write) {
125 return true;
129 return false;
132 bool aio_poll(AioContext *ctx, bool blocking)
134 static struct timeval tv0;
135 AioHandler *node;
136 fd_set rdfds, wrfds;
137 int max_fd = -1;
138 int ret;
139 bool busy, progress;
141 progress = false;
144 * If there are callbacks left that have been queued, we need to call then.
145 * Do not call select in this case, because it is possible that the caller
146 * does not need a complete flush (as is the case for qemu_aio_wait loops).
148 if (aio_bh_poll(ctx)) {
149 blocking = false;
150 progress = true;
154 * Then dispatch any pending callbacks from the GSource.
156 * We have to walk very carefully in case qemu_aio_set_fd_handler is
157 * called while we're walking.
159 node = QLIST_FIRST(&ctx->aio_handlers);
160 while (node) {
161 AioHandler *tmp;
162 int revents;
164 ctx->walking_handlers++;
166 revents = node->pfd.revents & node->pfd.events;
167 node->pfd.revents = 0;
169 /* See comment in aio_pending. */
170 if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read) {
171 node->io_read(node->opaque);
172 progress = true;
174 if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write) {
175 node->io_write(node->opaque);
176 progress = true;
179 tmp = node;
180 node = QLIST_NEXT(node, node);
182 ctx->walking_handlers--;
184 if (!ctx->walking_handlers && tmp->deleted) {
185 QLIST_REMOVE(tmp, node);
186 g_free(tmp);
190 if (progress && !blocking) {
191 return true;
194 ctx->walking_handlers++;
196 FD_ZERO(&rdfds);
197 FD_ZERO(&wrfds);
199 /* fill fd sets */
200 busy = false;
201 QLIST_FOREACH(node, &ctx->aio_handlers, node) {
202 /* If there aren't pending AIO operations, don't invoke callbacks.
203 * Otherwise, if there are no AIO requests, qemu_aio_wait() would
204 * wait indefinitely.
206 if (!node->deleted && node->io_flush) {
207 if (node->io_flush(node->opaque) == 0) {
208 continue;
210 busy = true;
212 if (!node->deleted && node->io_read) {
213 FD_SET(node->pfd.fd, &rdfds);
214 max_fd = MAX(max_fd, node->pfd.fd + 1);
216 if (!node->deleted && node->io_write) {
217 FD_SET(node->pfd.fd, &wrfds);
218 max_fd = MAX(max_fd, node->pfd.fd + 1);
222 ctx->walking_handlers--;
224 /* No AIO operations? Get us out of here */
225 if (!busy) {
226 return progress;
229 /* wait until next event */
230 ret = select(max_fd, &rdfds, &wrfds, NULL, blocking ? NULL : &tv0);
232 /* if we have any readable fds, dispatch event */
233 if (ret > 0) {
234 /* we have to walk very carefully in case
235 * qemu_aio_set_fd_handler is called while we're walking */
236 node = QLIST_FIRST(&ctx->aio_handlers);
237 while (node) {
238 AioHandler *tmp;
240 ctx->walking_handlers++;
242 if (!node->deleted &&
243 FD_ISSET(node->pfd.fd, &rdfds) &&
244 node->io_read) {
245 node->io_read(node->opaque);
246 progress = true;
248 if (!node->deleted &&
249 FD_ISSET(node->pfd.fd, &wrfds) &&
250 node->io_write) {
251 node->io_write(node->opaque);
252 progress = true;
255 tmp = node;
256 node = QLIST_NEXT(node, node);
258 ctx->walking_handlers--;
260 if (!ctx->walking_handlers && tmp->deleted) {
261 QLIST_REMOVE(tmp, node);
262 g_free(tmp);
267 assert(progress || busy);
268 return true;