| 1 | /* |
| 2 | * Linux native AIO support. |
| 3 | * |
| 4 | * Copyright (C) 2009 IBM, Corp. |
| 5 | * Copyright (C) 2009 Red Hat, Inc. |
| 6 | * |
| 7 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 8 | * See the COPYING file in the top-level directory. |
| 9 | */ |
| 10 | #include "qemu/osdep.h" |
| 11 | #include "qemu/aio.h" |
| 12 | #include "qemu/queue.h" |
| 13 | #include "block/block.h" |
| 14 | #include "block/raw-aio.h" |
| 15 | #include "qemu/event_notifier.h" |
| 16 | #include "qemu/coroutine.h" |
| 17 | #include "qemu/defer-call.h" |
| 18 | #include "qapi/error.h" |
| 19 | #include "system/block-backend.h" |
| 20 | |
| 21 | /* Only used for assertions. */ |
| 22 | #include "qemu/coroutine_int.h" |
| 23 | |
| 24 | #include <libaio.h> |
| 25 | |
| 26 | /* |
| 27 | * Queue size (per-device). |
| 28 | * |
| 29 | * XXX: eventually we need to communicate this to the guest and/or make it |
| 30 | * tunable by the guest. If we get more outstanding requests at a time |
| 31 | * than this we will get EAGAIN from io_submit which is communicated to |
| 32 | * the guest as an I/O error. |
| 33 | */ |
| 34 | #define MAX_EVENTS 1024 |
| 35 | |
| 36 | /* Maximum number of requests in a batch. (default value) */ |
| 37 | #define DEFAULT_MAX_BATCH 32 |
| 38 | |
| 39 | /* |
| 40 | * Bound on how deep ioq_submit() may recurse on a single LaioQueue via the |
| 41 | * ioq_submit -> qemu_laio_process_completions -> defer_call_end -> |
| 42 | * laio_deferred_fn -> ioq_submit cycle. The cycle terminates naturally |
| 43 | * when io_submit(2) returns asynchronously (O_DIRECT), but can grow |
| 44 | * without bound when submissions complete synchronously. On overflow |
| 45 | * the caller returns without submitting; the outermost |
| 46 | * qemu_laio_process_completions() has already scheduled s->completion_bh |
| 47 | * (via qemu_bh_schedule() at the top of that function), which resumes |
| 48 | * submission from the next event-loop dispatch. |
| 49 | */ |
| 50 | #define IOQ_SUBMIT_MAX_DEPTH 8 |
| 51 | |
| 52 | struct qemu_laiocb { |
| 53 | Coroutine *co; |
| 54 | LinuxAioState *ctx; |
| 55 | struct iocb iocb; |
| 56 | ssize_t ret; |
| 57 | off_t offset; |
| 58 | size_t nbytes; |
| 59 | QEMUIOVector *qiov; |
| 60 | |
| 61 | /* For handling short reads/writes */ |
| 62 | size_t total_done; |
| 63 | QEMUIOVector resubmit_qiov; |
| 64 | |
| 65 | int fd; |
| 66 | int type; |
| 67 | BdrvRequestFlags flags; |
| 68 | |
| 69 | uint64_t dev_max_batch; |
| 70 | QSIMPLEQ_ENTRY(qemu_laiocb) next; |
| 71 | }; |
| 72 | |
| 73 | typedef struct { |
| 74 | unsigned int in_queue; |
| 75 | unsigned int in_flight; |
| 76 | bool blocked; |
| 77 | unsigned int submit_depth; |
| 78 | QSIMPLEQ_HEAD(, qemu_laiocb) pending; |
| 79 | } LaioQueue; |
| 80 | |
| 81 | struct LinuxAioState { |
| 82 | AioContext *aio_context; |
| 83 | |
| 84 | io_context_t ctx; |
| 85 | EventNotifier e; |
| 86 | |
| 87 | /* No locking required, only accessed from AioContext home thread */ |
| 88 | LaioQueue io_q; |
| 89 | QEMUBH *completion_bh; |
| 90 | int event_idx; |
| 91 | int event_max; |
| 92 | }; |
| 93 | |
| 94 | static void ioq_submit(LinuxAioState *s); |
| 95 | static int laio_do_submit(struct qemu_laiocb *laiocb); |
| 96 | |
| 97 | static inline ssize_t io_event_ret(struct io_event *ev) |
| 98 | { |
| 99 | return (ssize_t)(((uint64_t)ev->res2 << 32) | ev->res); |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * Retry tail of short requests. |
| 104 | */ |
| 105 | static int laio_resubmit_short_io(struct qemu_laiocb *laiocb, size_t done) |
| 106 | { |
| 107 | QEMUIOVector *resubmit_qiov = &laiocb->resubmit_qiov; |
| 108 | |
| 109 | laiocb->total_done += done; |
| 110 | |
| 111 | if (!resubmit_qiov->iov) { |
| 112 | qemu_iovec_init(resubmit_qiov, laiocb->qiov->niov); |
| 113 | } else { |
| 114 | qemu_iovec_reset(resubmit_qiov); |
| 115 | } |
| 116 | qemu_iovec_concat(resubmit_qiov, laiocb->qiov, |
| 117 | laiocb->total_done, laiocb->nbytes - laiocb->total_done); |
| 118 | |
| 119 | return laio_do_submit(laiocb); |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Completes an AIO request. |
| 124 | */ |
| 125 | static void qemu_laio_process_completion(struct qemu_laiocb *laiocb) |
| 126 | { |
| 127 | ssize_t ret; |
| 128 | |
| 129 | ret = laiocb->ret; |
| 130 | if (ret != -ECANCELED) { |
| 131 | if (ret == laiocb->nbytes - laiocb->total_done) { |
| 132 | ret = 0; |
| 133 | } else if (ret > 0 && (laiocb->type == QEMU_AIO_READ || |
| 134 | laiocb->type == QEMU_AIO_WRITE)) { |
| 135 | ret = laio_resubmit_short_io(laiocb, ret); |
| 136 | if (!ret) { |
| 137 | return; |
| 138 | } |
| 139 | } else if (ret >= 0) { |
| 140 | /* |
| 141 | * For normal reads and writes, we only get here if ret == 0, which |
| 142 | * means EOF for reads and ENOSPC for writes. |
| 143 | * For zone-append, we get here with any ret >= 0, which we just |
| 144 | * treat as ENOSPC, too (safer than resubmitting, probably, but not |
| 145 | * 100 % clear). |
| 146 | */ |
| 147 | if (laiocb->type == QEMU_AIO_READ) { |
| 148 | qemu_iovec_memset(laiocb->qiov, laiocb->total_done, 0, |
| 149 | laiocb->qiov->size - laiocb->total_done); |
| 150 | } else { |
| 151 | ret = -ENOSPC; |
| 152 | } |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | laiocb->ret = ret; |
| 157 | if (laiocb->resubmit_qiov.iov) { |
| 158 | qemu_iovec_destroy(&laiocb->resubmit_qiov); |
| 159 | } |
| 160 | |
| 161 | /* |
| 162 | * If the coroutine is already entered it must be in ioq_submit() and |
| 163 | * will notice laio->ret has been filled in when it eventually runs |
| 164 | * later. Coroutines cannot be entered recursively so avoid doing |
| 165 | * that! |
| 166 | */ |
| 167 | assert(laiocb->co->ctx == laiocb->ctx->aio_context); |
| 168 | if (!qemu_coroutine_entered(laiocb->co)) { |
| 169 | aio_co_wake(laiocb->co); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | * aio_ring buffer which is shared between userspace and kernel. |
| 175 | * |
| 176 | * This copied from linux/fs/aio.c, common header does not exist |
| 177 | * but AIO exists for ages so we assume ABI is stable. |
| 178 | */ |
| 179 | struct aio_ring { |
| 180 | unsigned id; /* kernel internal index number */ |
| 181 | unsigned nr; /* number of io_events */ |
| 182 | unsigned head; /* Written to by userland or by kernel. */ |
| 183 | unsigned tail; |
| 184 | |
| 185 | unsigned magic; |
| 186 | unsigned compat_features; |
| 187 | unsigned incompat_features; |
| 188 | unsigned header_length; /* size of aio_ring */ |
| 189 | |
| 190 | struct io_event io_events[]; |
| 191 | }; |
| 192 | |
| 193 | /** |
| 194 | * io_getevents_peek: |
| 195 | * @ctx: AIO context |
| 196 | * @events: pointer on events array, output value |
| 197 | |
| 198 | * Returns the number of completed events and sets a pointer |
| 199 | * on events array. This function does not update the internal |
| 200 | * ring buffer, only reads head and tail. When @events has been |
| 201 | * processed io_getevents_commit() must be called. |
| 202 | */ |
| 203 | static inline unsigned int io_getevents_peek(io_context_t ctx, |
| 204 | struct io_event **events) |
| 205 | { |
| 206 | struct aio_ring *ring = (struct aio_ring *)ctx; |
| 207 | unsigned int head = ring->head, tail = ring->tail; |
| 208 | unsigned int nr; |
| 209 | |
| 210 | nr = tail >= head ? tail - head : ring->nr - head; |
| 211 | *events = ring->io_events + head; |
| 212 | /* To avoid speculative loads of s->events[i] before observing tail. |
| 213 | Paired with smp_wmb() inside linux/fs/aio.c: aio_complete(). */ |
| 214 | smp_rmb(); |
| 215 | |
| 216 | return nr; |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * io_getevents_commit: |
| 221 | * @ctx: AIO context |
| 222 | * @nr: the number of events on which head should be advanced |
| 223 | * |
| 224 | * Advances head of a ring buffer. |
| 225 | */ |
| 226 | static inline void io_getevents_commit(io_context_t ctx, unsigned int nr) |
| 227 | { |
| 228 | struct aio_ring *ring = (struct aio_ring *)ctx; |
| 229 | |
| 230 | if (nr) { |
| 231 | ring->head = (ring->head + nr) % ring->nr; |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | /** |
| 236 | * io_getevents_advance_and_peek: |
| 237 | * @ctx: AIO context |
| 238 | * @events: pointer on events array, output value |
| 239 | * @nr: the number of events on which head should be advanced |
| 240 | * |
| 241 | * Advances head of a ring buffer and returns number of elements left. |
| 242 | */ |
| 243 | static inline unsigned int |
| 244 | io_getevents_advance_and_peek(io_context_t ctx, |
| 245 | struct io_event **events, |
| 246 | unsigned int nr) |
| 247 | { |
| 248 | io_getevents_commit(ctx, nr); |
| 249 | return io_getevents_peek(ctx, events); |
| 250 | } |
| 251 | |
| 252 | /** |
| 253 | * qemu_laio_process_completions: |
| 254 | * @s: AIO state |
| 255 | * |
| 256 | * Fetches completed I/O requests and invokes their callbacks. |
| 257 | * |
| 258 | * The function is somewhat tricky because it supports nested event loops, for |
| 259 | * example when a request callback invokes aio_poll(). In order to do this, |
| 260 | * indices are kept in LinuxAioState. Function schedules BH completion so it |
| 261 | * can be called again in a nested event loop. When there are no events left |
| 262 | * to complete the BH is being canceled. |
| 263 | */ |
| 264 | static void qemu_laio_process_completions(LinuxAioState *s) |
| 265 | { |
| 266 | struct io_event *events; |
| 267 | |
| 268 | defer_call_begin(); |
| 269 | |
| 270 | /* Reschedule so nested event loops see currently pending completions */ |
| 271 | qemu_bh_schedule(s->completion_bh); |
| 272 | |
| 273 | while ((s->event_max = io_getevents_advance_and_peek(s->ctx, &events, |
| 274 | s->event_idx))) { |
| 275 | for (s->event_idx = 0; s->event_idx < s->event_max; ) { |
| 276 | struct iocb *iocb = events[s->event_idx].obj; |
| 277 | struct qemu_laiocb *laiocb = |
| 278 | container_of(iocb, struct qemu_laiocb, iocb); |
| 279 | |
| 280 | laiocb->ret = io_event_ret(&events[s->event_idx]); |
| 281 | |
| 282 | /* Change counters one-by-one because we can be nested. */ |
| 283 | s->io_q.in_flight--; |
| 284 | s->event_idx++; |
| 285 | qemu_laio_process_completion(laiocb); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | qemu_bh_cancel(s->completion_bh); |
| 290 | |
| 291 | /* If we are nested we have to notify the level above that we are done |
| 292 | * by setting event_max to zero, upper level will then jump out of it's |
| 293 | * own `for` loop. If we are the last all counters dropped to zero. */ |
| 294 | s->event_max = 0; |
| 295 | s->event_idx = 0; |
| 296 | |
| 297 | defer_call_end(); |
| 298 | } |
| 299 | |
| 300 | static void qemu_laio_process_completions_and_submit(LinuxAioState *s) |
| 301 | { |
| 302 | qemu_laio_process_completions(s); |
| 303 | |
| 304 | if (!QSIMPLEQ_EMPTY(&s->io_q.pending)) { |
| 305 | ioq_submit(s); |
| 306 | } |
| 307 | } |
| 308 | |
| 309 | static void qemu_laio_completion_bh(void *opaque) |
| 310 | { |
| 311 | LinuxAioState *s = opaque; |
| 312 | |
| 313 | qemu_laio_process_completions_and_submit(s); |
| 314 | } |
| 315 | |
| 316 | static void qemu_laio_completion_cb(EventNotifier *e) |
| 317 | { |
| 318 | LinuxAioState *s = container_of(e, LinuxAioState, e); |
| 319 | |
| 320 | if (event_notifier_test_and_clear(&s->e)) { |
| 321 | qemu_laio_process_completions_and_submit(s); |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | static bool qemu_laio_poll_cb(void *opaque) |
| 326 | { |
| 327 | EventNotifier *e = opaque; |
| 328 | LinuxAioState *s = container_of(e, LinuxAioState, e); |
| 329 | struct io_event *events; |
| 330 | |
| 331 | return io_getevents_peek(s->ctx, &events); |
| 332 | } |
| 333 | |
| 334 | static void qemu_laio_poll_ready(EventNotifier *opaque) |
| 335 | { |
| 336 | EventNotifier *e = opaque; |
| 337 | LinuxAioState *s = container_of(e, LinuxAioState, e); |
| 338 | |
| 339 | qemu_laio_process_completions_and_submit(s); |
| 340 | } |
| 341 | |
| 342 | static void ioq_init(LaioQueue *io_q) |
| 343 | { |
| 344 | QSIMPLEQ_INIT(&io_q->pending); |
| 345 | io_q->in_queue = 0; |
| 346 | io_q->in_flight = 0; |
| 347 | io_q->blocked = false; |
| 348 | io_q->submit_depth = 0; |
| 349 | } |
| 350 | |
| 351 | static void ioq_submit(LinuxAioState *s) |
| 352 | { |
| 353 | int ret, len; |
| 354 | struct qemu_laiocb *aiocb; |
| 355 | QEMU_UNINITIALIZED struct iocb *iocbs[MAX_EVENTS]; |
| 356 | QSIMPLEQ_HEAD(, qemu_laiocb) completed; |
| 357 | |
| 358 | if (s->io_q.submit_depth >= IOQ_SUBMIT_MAX_DEPTH) { |
| 359 | return; |
| 360 | } |
| 361 | s->io_q.submit_depth++; |
| 362 | |
| 363 | do { |
| 364 | if (s->io_q.in_flight >= MAX_EVENTS) { |
| 365 | break; |
| 366 | } |
| 367 | len = 0; |
| 368 | QSIMPLEQ_FOREACH(aiocb, &s->io_q.pending, next) { |
| 369 | iocbs[len++] = &aiocb->iocb; |
| 370 | if (s->io_q.in_flight + len >= MAX_EVENTS) { |
| 371 | break; |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | ret = io_submit(s->ctx, len, iocbs); |
| 376 | if (ret == -EAGAIN) { |
| 377 | break; |
| 378 | } |
| 379 | if (ret < 0) { |
| 380 | /* Fail the first request, retry the rest */ |
| 381 | aiocb = QSIMPLEQ_FIRST(&s->io_q.pending); |
| 382 | QSIMPLEQ_REMOVE_HEAD(&s->io_q.pending, next); |
| 383 | s->io_q.in_queue--; |
| 384 | aiocb->ret = ret; |
| 385 | qemu_laio_process_completion(aiocb); |
| 386 | continue; |
| 387 | } |
| 388 | |
| 389 | s->io_q.in_flight += ret; |
| 390 | s->io_q.in_queue -= ret; |
| 391 | aiocb = container_of(iocbs[ret - 1], struct qemu_laiocb, iocb); |
| 392 | QSIMPLEQ_SPLIT_AFTER(&s->io_q.pending, aiocb, next, &completed); |
| 393 | } while (ret == len && !QSIMPLEQ_EMPTY(&s->io_q.pending)); |
| 394 | s->io_q.blocked = (s->io_q.in_queue > 0); |
| 395 | |
| 396 | if (s->io_q.in_flight) { |
| 397 | /* We can try to complete something just right away if there are |
| 398 | * still requests in-flight. */ |
| 399 | qemu_laio_process_completions(s); |
| 400 | /* |
| 401 | * Even we have completed everything (in_flight == 0), the queue can |
| 402 | * have still pended requests (in_queue > 0). We do not attempt to |
| 403 | * repeat submission to avoid IO hang. The reason is simple: s->e is |
| 404 | * still set and completion callback will be called shortly and all |
| 405 | * pended requests will be submitted from there. |
| 406 | */ |
| 407 | } |
| 408 | |
| 409 | s->io_q.submit_depth--; |
| 410 | } |
| 411 | |
| 412 | static uint64_t laio_max_batch(LinuxAioState *s, uint64_t dev_max_batch) |
| 413 | { |
| 414 | uint64_t max_batch = s->aio_context->aio_max_batch ?: DEFAULT_MAX_BATCH; |
| 415 | |
| 416 | /* |
| 417 | * AIO context can be shared between multiple block devices, so |
| 418 | * `dev_max_batch` allows reducing the batch size for latency-sensitive |
| 419 | * devices. |
| 420 | */ |
| 421 | max_batch = MIN_NON_ZERO(dev_max_batch, max_batch); |
| 422 | |
| 423 | /* limit the batch with the number of available events */ |
| 424 | max_batch = MIN_NON_ZERO(MAX_EVENTS - s->io_q.in_flight, max_batch); |
| 425 | |
| 426 | return max_batch; |
| 427 | } |
| 428 | |
| 429 | static void laio_deferred_fn(void *opaque) |
| 430 | { |
| 431 | LinuxAioState *s = opaque; |
| 432 | |
| 433 | if (!s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) { |
| 434 | ioq_submit(s); |
| 435 | } |
| 436 | } |
| 437 | |
| 438 | static int laio_do_submit(struct qemu_laiocb *laiocb) |
| 439 | { |
| 440 | LinuxAioState *s = laiocb->ctx; |
| 441 | struct iocb *iocbs = &laiocb->iocb; |
| 442 | QEMUIOVector *qiov = laiocb->qiov; |
| 443 | int fd = laiocb->fd; |
| 444 | off_t offset = laiocb->offset + laiocb->total_done; |
| 445 | |
| 446 | if (laiocb->resubmit_qiov.iov) { |
| 447 | qiov = &laiocb->resubmit_qiov; |
| 448 | } |
| 449 | |
| 450 | switch (laiocb->type) { |
| 451 | case QEMU_AIO_WRITE: |
| 452 | #ifdef HAVE_IO_PREP_PWRITEV2 |
| 453 | { |
| 454 | int laio_flags = (laiocb->flags & BDRV_REQ_FUA) ? RWF_DSYNC : 0; |
| 455 | io_prep_pwritev2(iocbs, fd, qiov->iov, qiov->niov, offset, laio_flags); |
| 456 | } |
| 457 | #else |
| 458 | assert(laiocb->flags == 0); |
| 459 | io_prep_pwritev(iocbs, fd, qiov->iov, qiov->niov, offset); |
| 460 | #endif |
| 461 | break; |
| 462 | case QEMU_AIO_ZONE_APPEND: |
| 463 | io_prep_pwritev(iocbs, fd, qiov->iov, qiov->niov, offset); |
| 464 | break; |
| 465 | case QEMU_AIO_READ: |
| 466 | io_prep_preadv(iocbs, fd, qiov->iov, qiov->niov, offset); |
| 467 | break; |
| 468 | case QEMU_AIO_FLUSH: |
| 469 | io_prep_fdsync(iocbs, fd); |
| 470 | break; |
| 471 | /* Currently Linux kernel does not support other operations */ |
| 472 | default: |
| 473 | fprintf(stderr, "%s: invalid AIO request type 0x%x.\n", |
| 474 | __func__, laiocb->type); |
| 475 | return -EIO; |
| 476 | } |
| 477 | io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e)); |
| 478 | |
| 479 | QSIMPLEQ_INSERT_TAIL(&s->io_q.pending, laiocb, next); |
| 480 | s->io_q.in_queue++; |
| 481 | if (!s->io_q.blocked) { |
| 482 | if (s->io_q.in_queue >= laio_max_batch(s, laiocb->dev_max_batch)) { |
| 483 | ioq_submit(s); |
| 484 | } else { |
| 485 | defer_call(laio_deferred_fn, s); |
| 486 | } |
| 487 | } |
| 488 | |
| 489 | return 0; |
| 490 | } |
| 491 | |
| 492 | int coroutine_fn laio_co_submit(int fd, uint64_t offset, QEMUIOVector *qiov, |
| 493 | int type, BdrvRequestFlags flags, |
| 494 | uint64_t dev_max_batch) |
| 495 | { |
| 496 | int ret; |
| 497 | AioContext *ctx = qemu_get_current_aio_context(); |
| 498 | struct qemu_laiocb laiocb = { |
| 499 | .co = qemu_coroutine_self(), |
| 500 | .offset = offset, |
| 501 | .nbytes = qiov ? qiov->size : 0, |
| 502 | .ctx = aio_get_linux_aio(ctx), |
| 503 | .ret = -EINPROGRESS, |
| 504 | .qiov = qiov, |
| 505 | .fd = fd, |
| 506 | .type = type, |
| 507 | .flags = flags, |
| 508 | .dev_max_batch = dev_max_batch, |
| 509 | }; |
| 510 | |
| 511 | ret = laio_do_submit(&laiocb); |
| 512 | if (ret < 0) { |
| 513 | return ret; |
| 514 | } |
| 515 | |
| 516 | if (laiocb.ret == -EINPROGRESS) { |
| 517 | qemu_coroutine_yield(); |
| 518 | } |
| 519 | return laiocb.ret; |
| 520 | } |
| 521 | |
| 522 | void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context) |
| 523 | { |
| 524 | aio_set_event_notifier(old_context, &s->e, NULL, NULL, NULL); |
| 525 | qemu_bh_delete(s->completion_bh); |
| 526 | s->aio_context = NULL; |
| 527 | } |
| 528 | |
| 529 | void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context) |
| 530 | { |
| 531 | s->aio_context = new_context; |
| 532 | s->completion_bh = aio_bh_new(new_context, qemu_laio_completion_bh, s); |
| 533 | aio_set_event_notifier(new_context, &s->e, |
| 534 | qemu_laio_completion_cb, |
| 535 | qemu_laio_poll_cb, |
| 536 | qemu_laio_poll_ready); |
| 537 | } |
| 538 | |
| 539 | LinuxAioState *laio_init(Error **errp) |
| 540 | { |
| 541 | int rc; |
| 542 | LinuxAioState *s; |
| 543 | |
| 544 | s = g_malloc0(sizeof(*s)); |
| 545 | rc = event_notifier_init(&s->e, false); |
| 546 | if (rc < 0) { |
| 547 | error_setg_errno(errp, -rc, "failed to initialize event notifier"); |
| 548 | goto out_free_state; |
| 549 | } |
| 550 | |
| 551 | rc = io_setup(MAX_EVENTS, &s->ctx); |
| 552 | if (rc < 0) { |
| 553 | error_setg_errno(errp, -rc, "failed to create linux AIO context"); |
| 554 | goto out_close_efd; |
| 555 | } |
| 556 | |
| 557 | ioq_init(&s->io_q); |
| 558 | |
| 559 | return s; |
| 560 | |
| 561 | out_close_efd: |
| 562 | event_notifier_cleanup(&s->e); |
| 563 | out_free_state: |
| 564 | g_free(s); |
| 565 | return NULL; |
| 566 | } |
| 567 | |
| 568 | void laio_cleanup(LinuxAioState *s) |
| 569 | { |
| 570 | event_notifier_cleanup(&s->e); |
| 571 | |
| 572 | if (io_destroy(s->ctx) != 0) { |
| 573 | fprintf(stderr, "%s: destroy AIO context %p failed\n", |
| 574 | __func__, &s->ctx); |
| 575 | } |
| 576 | g_free(s); |
| 577 | } |
| 578 | |
| 579 | bool laio_has_fdsync(int fd) |
| 580 | { |
| 581 | struct iocb cb; |
| 582 | struct iocb *cbs[] = {&cb, NULL}; |
| 583 | |
| 584 | io_context_t ctx = 0; |
| 585 | io_setup(1, &ctx); |
| 586 | |
| 587 | /* check if host kernel supports IO_CMD_FDSYNC */ |
| 588 | io_prep_fdsync(&cb, fd); |
| 589 | int ret = io_submit(ctx, 1, cbs); |
| 590 | |
| 591 | io_destroy(ctx); |
| 592 | return (ret == -EINVAL) ? false : true; |
| 593 | } |
| 594 | |
| 595 | bool laio_has_fua(void) |
| 596 | { |
| 597 | #ifdef HAVE_IO_PREP_PWRITEV2 |
| 598 | return true; |
| 599 | #else |
| 600 | return false; |
| 601 | #endif |
| 602 | } |