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26#include "qemu/osdep.h"
27#include "qapi/error.h"
28#include "qemu-common.h"
29#include "block/aio.h"
30#include "block/thread-pool.h"
31#include "qemu/main-loop.h"
32#include "qemu/atomic.h"
33#include "block/raw-aio.h"
34#include "qemu/coroutine_int.h"
35#include "trace.h"
36
37
38
39
40struct QEMUBH {
41 AioContext *ctx;
42 QEMUBHFunc *cb;
43 void *opaque;
44 QEMUBH *next;
45 bool scheduled;
46 bool idle;
47 bool deleted;
48};
49
50void aio_bh_schedule_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
51{
52 QEMUBH *bh;
53 bh = g_new(QEMUBH, 1);
54 *bh = (QEMUBH){
55 .ctx = ctx,
56 .cb = cb,
57 .opaque = opaque,
58 };
59 qemu_lockcnt_lock(&ctx->list_lock);
60 bh->next = ctx->first_bh;
61 bh->scheduled = 1;
62 bh->deleted = 1;
63
64 smp_wmb();
65 ctx->first_bh = bh;
66 qemu_lockcnt_unlock(&ctx->list_lock);
67 aio_notify(ctx);
68}
69
70QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
71{
72 QEMUBH *bh;
73 bh = g_new(QEMUBH, 1);
74 *bh = (QEMUBH){
75 .ctx = ctx,
76 .cb = cb,
77 .opaque = opaque,
78 };
79 qemu_lockcnt_lock(&ctx->list_lock);
80 bh->next = ctx->first_bh;
81
82 smp_wmb();
83 ctx->first_bh = bh;
84 qemu_lockcnt_unlock(&ctx->list_lock);
85 return bh;
86}
87
88void aio_bh_call(QEMUBH *bh)
89{
90 bh->cb(bh->opaque);
91}
92
93
94
95
96
97int aio_bh_poll(AioContext *ctx)
98{
99 QEMUBH *bh, **bhp, *next;
100 int ret;
101 bool deleted = false;
102
103 ret = 0;
104 for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) {
105 next = atomic_rcu_read(&bh->next);
106
107
108
109
110
111
112 if (atomic_xchg(&bh->scheduled, 0)) {
113
114 if (!bh->idle) {
115 ret = 1;
116 }
117 bh->idle = 0;
118 aio_bh_call(bh);
119 }
120 if (bh->deleted) {
121 deleted = true;
122 }
123 }
124
125
126 if (!deleted) {
127 return ret;
128 }
129
130 if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
131 bhp = &ctx->first_bh;
132 while (*bhp) {
133 bh = *bhp;
134 if (bh->deleted && !bh->scheduled) {
135 *bhp = bh->next;
136 g_free(bh);
137 } else {
138 bhp = &bh->next;
139 }
140 }
141 qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
142 }
143 return ret;
144}
145
146void qemu_bh_schedule_idle(QEMUBH *bh)
147{
148 bh->idle = 1;
149
150
151
152 atomic_mb_set(&bh->scheduled, 1);
153}
154
155void qemu_bh_schedule(QEMUBH *bh)
156{
157 AioContext *ctx;
158
159 ctx = bh->ctx;
160 bh->idle = 0;
161
162
163
164
165
166
167 if (atomic_xchg(&bh->scheduled, 1) == 0) {
168 aio_notify(ctx);
169 }
170}
171
172
173
174
175void qemu_bh_cancel(QEMUBH *bh)
176{
177 atomic_mb_set(&bh->scheduled, 0);
178}
179
180
181
182
183void qemu_bh_delete(QEMUBH *bh)
184{
185 bh->scheduled = 0;
186 bh->deleted = 1;
187}
188
189int64_t
190aio_compute_timeout(AioContext *ctx)
191{
192 int64_t deadline;
193 int timeout = -1;
194 QEMUBH *bh;
195
196 for (bh = atomic_rcu_read(&ctx->first_bh); bh;
197 bh = atomic_rcu_read(&bh->next)) {
198 if (bh->scheduled) {
199 if (bh->idle) {
200
201
202 timeout = 10000000;
203 } else {
204
205
206 return 0;
207 }
208 }
209 }
210
211 deadline = timerlistgroup_deadline_ns(&ctx->tlg);
212 if (deadline == 0) {
213 return 0;
214 } else {
215 return qemu_soonest_timeout(timeout, deadline);
216 }
217}
218
219static gboolean
220aio_ctx_prepare(GSource *source, gint *timeout)
221{
222 AioContext *ctx = (AioContext *) source;
223
224 atomic_or(&ctx->notify_me, 1);
225
226
227 *timeout = qemu_timeout_ns_to_ms(aio_compute_timeout(ctx));
228
229 if (aio_prepare(ctx)) {
230 *timeout = 0;
231 }
232
233 return *timeout == 0;
234}
235
236static gboolean
237aio_ctx_check(GSource *source)
238{
239 AioContext *ctx = (AioContext *) source;
240 QEMUBH *bh;
241
242 atomic_and(&ctx->notify_me, ~1);
243 aio_notify_accept(ctx);
244
245 for (bh = ctx->first_bh; bh; bh = bh->next) {
246 if (bh->scheduled) {
247 return true;
248 }
249 }
250 return aio_pending(ctx) || (timerlistgroup_deadline_ns(&ctx->tlg) == 0);
251}
252
253static gboolean
254aio_ctx_dispatch(GSource *source,
255 GSourceFunc callback,
256 gpointer user_data)
257{
258 AioContext *ctx = (AioContext *) source;
259
260 assert(callback == NULL);
261 aio_dispatch(ctx);
262 return true;
263}
264
265static void
266aio_ctx_finalize(GSource *source)
267{
268 AioContext *ctx = (AioContext *) source;
269
270 thread_pool_free(ctx->thread_pool);
271
272#ifdef CONFIG_LINUX_AIO
273 if (ctx->linux_aio) {
274 laio_detach_aio_context(ctx->linux_aio, ctx);
275 laio_cleanup(ctx->linux_aio);
276 ctx->linux_aio = NULL;
277 }
278#endif
279
280 assert(QSLIST_EMPTY(&ctx->scheduled_coroutines));
281 qemu_bh_delete(ctx->co_schedule_bh);
282
283 qemu_lockcnt_lock(&ctx->list_lock);
284 assert(!qemu_lockcnt_count(&ctx->list_lock));
285 while (ctx->first_bh) {
286 QEMUBH *next = ctx->first_bh->next;
287
288
289 assert(ctx->first_bh->deleted);
290
291 g_free(ctx->first_bh);
292 ctx->first_bh = next;
293 }
294 qemu_lockcnt_unlock(&ctx->list_lock);
295
296 aio_set_event_notifier(ctx, &ctx->notifier, false, NULL, NULL);
297 event_notifier_cleanup(&ctx->notifier);
298 qemu_rec_mutex_destroy(&ctx->lock);
299 qemu_lockcnt_destroy(&ctx->list_lock);
300 timerlistgroup_deinit(&ctx->tlg);
301 aio_context_destroy(ctx);
302}
303
304static GSourceFuncs aio_source_funcs = {
305 aio_ctx_prepare,
306 aio_ctx_check,
307 aio_ctx_dispatch,
308 aio_ctx_finalize
309};
310
311GSource *aio_get_g_source(AioContext *ctx)
312{
313 g_source_ref(&ctx->source);
314 return &ctx->source;
315}
316
317ThreadPool *aio_get_thread_pool(AioContext *ctx)
318{
319 if (!ctx->thread_pool) {
320 ctx->thread_pool = thread_pool_new(ctx);
321 }
322 return ctx->thread_pool;
323}
324
325#ifdef CONFIG_LINUX_AIO
326LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp)
327{
328 if (!ctx->linux_aio) {
329 ctx->linux_aio = laio_init(errp);
330 if (ctx->linux_aio) {
331 laio_attach_aio_context(ctx->linux_aio, ctx);
332 }
333 }
334 return ctx->linux_aio;
335}
336
337LinuxAioState *aio_get_linux_aio(AioContext *ctx)
338{
339 assert(ctx->linux_aio);
340 return ctx->linux_aio;
341}
342#endif
343
344void aio_notify(AioContext *ctx)
345{
346
347
348
349 smp_mb();
350 if (ctx->notify_me) {
351 event_notifier_set(&ctx->notifier);
352 atomic_mb_set(&ctx->notified, true);
353 }
354}
355
356void aio_notify_accept(AioContext *ctx)
357{
358 if (atomic_xchg(&ctx->notified, false)) {
359 event_notifier_test_and_clear(&ctx->notifier);
360 }
361}
362
363static void aio_timerlist_notify(void *opaque, QEMUClockType type)
364{
365 aio_notify(opaque);
366}
367
368static void event_notifier_dummy_cb(EventNotifier *e)
369{
370}
371
372
373static bool event_notifier_poll(void *opaque)
374{
375 EventNotifier *e = opaque;
376 AioContext *ctx = container_of(e, AioContext, notifier);
377
378 return atomic_read(&ctx->notified);
379}
380
381static void co_schedule_bh_cb(void *opaque)
382{
383 AioContext *ctx = opaque;
384 QSLIST_HEAD(, Coroutine) straight, reversed;
385
386 QSLIST_MOVE_ATOMIC(&reversed, &ctx->scheduled_coroutines);
387 QSLIST_INIT(&straight);
388
389 while (!QSLIST_EMPTY(&reversed)) {
390 Coroutine *co = QSLIST_FIRST(&reversed);
391 QSLIST_REMOVE_HEAD(&reversed, co_scheduled_next);
392 QSLIST_INSERT_HEAD(&straight, co, co_scheduled_next);
393 }
394
395 while (!QSLIST_EMPTY(&straight)) {
396 Coroutine *co = QSLIST_FIRST(&straight);
397 QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
398 trace_aio_co_schedule_bh_cb(ctx, co);
399 aio_context_acquire(ctx);
400
401
402 atomic_set(&co->scheduled, NULL);
403 qemu_coroutine_enter(co);
404 aio_context_release(ctx);
405 }
406}
407
408AioContext *aio_context_new(Error **errp)
409{
410 int ret;
411 AioContext *ctx;
412
413 ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
414 aio_context_setup(ctx);
415
416 ret = event_notifier_init(&ctx->notifier, false);
417 if (ret < 0) {
418 error_setg_errno(errp, -ret, "Failed to initialize event notifier");
419 goto fail;
420 }
421 g_source_set_can_recurse(&ctx->source, true);
422 qemu_lockcnt_init(&ctx->list_lock);
423
424 ctx->co_schedule_bh = aio_bh_new(ctx, co_schedule_bh_cb, ctx);
425 QSLIST_INIT(&ctx->scheduled_coroutines);
426
427 aio_set_event_notifier(ctx, &ctx->notifier,
428 false,
429 (EventNotifierHandler *)
430 event_notifier_dummy_cb,
431 event_notifier_poll);
432#ifdef CONFIG_LINUX_AIO
433 ctx->linux_aio = NULL;
434#endif
435 ctx->thread_pool = NULL;
436 qemu_rec_mutex_init(&ctx->lock);
437 timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
438
439 ctx->poll_ns = 0;
440 ctx->poll_max_ns = 0;
441 ctx->poll_grow = 0;
442 ctx->poll_shrink = 0;
443
444 return ctx;
445fail:
446 g_source_destroy(&ctx->source);
447 return NULL;
448}
449
450void aio_co_schedule(AioContext *ctx, Coroutine *co)
451{
452 trace_aio_co_schedule(ctx, co);
453 const char *scheduled = atomic_cmpxchg(&co->scheduled, NULL,
454 __func__);
455
456 if (scheduled) {
457 fprintf(stderr,
458 "%s: Co-routine was already scheduled in '%s'\n",
459 __func__, scheduled);
460 abort();
461 }
462
463 QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines,
464 co, co_scheduled_next);
465 qemu_bh_schedule(ctx->co_schedule_bh);
466}
467
468void aio_co_wake(struct Coroutine *co)
469{
470 AioContext *ctx;
471
472
473
474
475 smp_read_barrier_depends();
476 ctx = atomic_read(&co->ctx);
477
478 aio_co_enter(ctx, co);
479}
480
481void aio_co_enter(AioContext *ctx, struct Coroutine *co)
482{
483 if (ctx != qemu_get_current_aio_context()) {
484 aio_co_schedule(ctx, co);
485 return;
486 }
487
488 if (qemu_in_coroutine()) {
489 Coroutine *self = qemu_coroutine_self();
490 assert(self != co);
491 QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, co, co_queue_next);
492 } else {
493 aio_context_acquire(ctx);
494 qemu_aio_coroutine_enter(ctx, co);
495 aio_context_release(ctx);
496 }
497}
498
499void aio_context_ref(AioContext *ctx)
500{
501 g_source_ref(&ctx->source);
502}
503
504void aio_context_unref(AioContext *ctx)
505{
506 g_source_unref(&ctx->source);
507}
508
509void aio_context_acquire(AioContext *ctx)
510{
511 qemu_rec_mutex_lock(&ctx->lock);
512}
513
514void aio_context_release(AioContext *ctx)
515{
516 qemu_rec_mutex_unlock(&ctx->lock);
517}
518