Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 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-common.h" |
Paolo Bonzini | 737e150 | 2012-12-17 18:19:44 +0100 | [diff] [blame] | 11 | #include "block/aio.h" |
Paolo Bonzini | 1de7afc | 2012-12-17 18:20:00 +0100 | [diff] [blame] | 12 | #include "qemu/queue.h" |
Paolo Bonzini | 9f8540e | 2012-06-09 10:57:37 +0200 | [diff] [blame] | 13 | #include "block/raw-aio.h" |
Paolo Bonzini | 1de7afc | 2012-12-17 18:20:00 +0100 | [diff] [blame] | 14 | #include "qemu/event_notifier.h" |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 15 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 16 | #include <libaio.h> |
| 17 | |
| 18 | /* |
| 19 | * Queue size (per-device). |
| 20 | * |
| 21 | * XXX: eventually we need to communicate this to the guest and/or make it |
| 22 | * tunable by the guest. If we get more outstanding requests at a time |
| 23 | * than this we will get EAGAIN from io_submit which is communicated to |
| 24 | * the guest as an I/O error. |
| 25 | */ |
| 26 | #define MAX_EVENTS 128 |
| 27 | |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 28 | #define MAX_QUEUED_IO 128 |
| 29 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 30 | struct qemu_laiocb { |
| 31 | BlockDriverAIOCB common; |
| 32 | struct qemu_laio_state *ctx; |
| 33 | struct iocb iocb; |
| 34 | ssize_t ret; |
| 35 | size_t nbytes; |
Kevin Wolf | b161e2e | 2011-10-13 15:42:52 +0200 | [diff] [blame] | 36 | QEMUIOVector *qiov; |
| 37 | bool is_read; |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 38 | QLIST_ENTRY(qemu_laiocb) node; |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 39 | }; |
| 40 | |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 41 | typedef struct { |
| 42 | struct iocb *iocbs[MAX_QUEUED_IO]; |
| 43 | int plugged; |
| 44 | unsigned int size; |
| 45 | unsigned int idx; |
| 46 | } LaioQueue; |
| 47 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 48 | struct qemu_laio_state { |
| 49 | io_context_t ctx; |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 50 | EventNotifier e; |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 51 | |
| 52 | /* io queue for submit at batch */ |
| 53 | LaioQueue io_q; |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 54 | }; |
| 55 | |
| 56 | static inline ssize_t io_event_ret(struct io_event *ev) |
| 57 | { |
| 58 | return (ssize_t)(((uint64_t)ev->res2 << 32) | ev->res); |
| 59 | } |
| 60 | |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 61 | /* |
| 62 | * Completes an AIO request (calls the callback and frees the ACB). |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 63 | */ |
| 64 | static void qemu_laio_process_completion(struct qemu_laio_state *s, |
| 65 | struct qemu_laiocb *laiocb) |
| 66 | { |
| 67 | int ret; |
| 68 | |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 69 | ret = laiocb->ret; |
| 70 | if (ret != -ECANCELED) { |
Kevin Wolf | b161e2e | 2011-10-13 15:42:52 +0200 | [diff] [blame] | 71 | if (ret == laiocb->nbytes) { |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 72 | ret = 0; |
Kevin Wolf | b161e2e | 2011-10-13 15:42:52 +0200 | [diff] [blame] | 73 | } else if (ret >= 0) { |
| 74 | /* Short reads mean EOF, pad with zeros. */ |
| 75 | if (laiocb->is_read) { |
Michael Tokarev | 3d9b492 | 2012-03-10 16:54:23 +0400 | [diff] [blame] | 76 | qemu_iovec_memset(laiocb->qiov, ret, 0, |
| 77 | laiocb->qiov->size - ret); |
Kevin Wolf | b161e2e | 2011-10-13 15:42:52 +0200 | [diff] [blame] | 78 | } else { |
| 79 | ret = -EINVAL; |
| 80 | } |
| 81 | } |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 82 | |
| 83 | laiocb->common.cb(laiocb->common.opaque, ret); |
| 84 | } |
| 85 | |
| 86 | qemu_aio_release(laiocb); |
| 87 | } |
| 88 | |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 89 | static void qemu_laio_completion_cb(EventNotifier *e) |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 90 | { |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 91 | struct qemu_laio_state *s = container_of(e, struct qemu_laio_state, e); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 92 | |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 93 | while (event_notifier_test_and_clear(&s->e)) { |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 94 | struct io_event events[MAX_EVENTS]; |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 95 | struct timespec ts = { 0 }; |
| 96 | int nevents, i; |
| 97 | |
| 98 | do { |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 99 | nevents = io_getevents(s->ctx, MAX_EVENTS, MAX_EVENTS, events, &ts); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 100 | } while (nevents == -EINTR); |
| 101 | |
| 102 | for (i = 0; i < nevents; i++) { |
| 103 | struct iocb *iocb = events[i].obj; |
| 104 | struct qemu_laiocb *laiocb = |
| 105 | container_of(iocb, struct qemu_laiocb, iocb); |
| 106 | |
Kevin Wolf | db0ffc2 | 2009-10-22 17:54:41 +0200 | [diff] [blame] | 107 | laiocb->ret = io_event_ret(&events[i]); |
Kevin Wolf | 384acbf | 2011-07-15 16:36:40 +0200 | [diff] [blame] | 108 | qemu_laio_process_completion(s, laiocb); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 109 | } |
| 110 | } |
| 111 | } |
| 112 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 113 | static void laio_cancel(BlockDriverAIOCB *blockacb) |
| 114 | { |
| 115 | struct qemu_laiocb *laiocb = (struct qemu_laiocb *)blockacb; |
| 116 | struct io_event event; |
| 117 | int ret; |
| 118 | |
| 119 | if (laiocb->ret != -EINPROGRESS) |
| 120 | return; |
| 121 | |
| 122 | /* |
| 123 | * Note that as of Linux 2.6.31 neither the block device code nor any |
| 124 | * filesystem implements cancellation of AIO request. |
| 125 | * Thus the polling loop below is the normal code path. |
| 126 | */ |
| 127 | ret = io_cancel(laiocb->ctx->ctx, &laiocb->iocb, &event); |
| 128 | if (ret == 0) { |
| 129 | laiocb->ret = -ECANCELED; |
| 130 | return; |
| 131 | } |
| 132 | |
| 133 | /* |
| 134 | * We have to wait for the iocb to finish. |
| 135 | * |
| 136 | * The only way to get the iocb status update is by polling the io context. |
| 137 | * We might be able to do this slightly more optimal by removing the |
| 138 | * O_NONBLOCK flag. |
| 139 | */ |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 140 | while (laiocb->ret == -EINPROGRESS) { |
| 141 | qemu_laio_completion_cb(&laiocb->ctx->e); |
| 142 | } |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 143 | } |
| 144 | |
Stefan Hajnoczi | d7331be | 2012-10-31 16:34:37 +0100 | [diff] [blame] | 145 | static const AIOCBInfo laio_aiocb_info = { |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 146 | .aiocb_size = sizeof(struct qemu_laiocb), |
| 147 | .cancel = laio_cancel, |
| 148 | }; |
| 149 | |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 150 | static void ioq_init(LaioQueue *io_q) |
| 151 | { |
| 152 | io_q->size = MAX_QUEUED_IO; |
| 153 | io_q->idx = 0; |
| 154 | io_q->plugged = 0; |
| 155 | } |
| 156 | |
| 157 | static int ioq_submit(struct qemu_laio_state *s) |
| 158 | { |
| 159 | int ret, i = 0; |
| 160 | int len = s->io_q.idx; |
| 161 | |
| 162 | do { |
| 163 | ret = io_submit(s->ctx, len, s->io_q.iocbs); |
| 164 | } while (i++ < 3 && ret == -EAGAIN); |
| 165 | |
| 166 | /* empty io queue */ |
| 167 | s->io_q.idx = 0; |
| 168 | |
| 169 | if (ret < 0) { |
| 170 | i = 0; |
| 171 | } else { |
| 172 | i = ret; |
| 173 | } |
| 174 | |
| 175 | for (; i < len; i++) { |
| 176 | struct qemu_laiocb *laiocb = |
| 177 | container_of(s->io_q.iocbs[i], struct qemu_laiocb, iocb); |
| 178 | |
| 179 | laiocb->ret = (ret < 0) ? ret : -EIO; |
| 180 | qemu_laio_process_completion(s, laiocb); |
| 181 | } |
| 182 | return ret; |
| 183 | } |
| 184 | |
| 185 | static void ioq_enqueue(struct qemu_laio_state *s, struct iocb *iocb) |
| 186 | { |
| 187 | unsigned int idx = s->io_q.idx; |
| 188 | |
| 189 | s->io_q.iocbs[idx++] = iocb; |
| 190 | s->io_q.idx = idx; |
| 191 | |
| 192 | /* submit immediately if queue is full */ |
| 193 | if (idx == s->io_q.size) { |
| 194 | ioq_submit(s); |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | void laio_io_plug(BlockDriverState *bs, void *aio_ctx) |
| 199 | { |
| 200 | struct qemu_laio_state *s = aio_ctx; |
| 201 | |
| 202 | s->io_q.plugged++; |
| 203 | } |
| 204 | |
| 205 | int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug) |
| 206 | { |
| 207 | struct qemu_laio_state *s = aio_ctx; |
| 208 | int ret = 0; |
| 209 | |
| 210 | assert(s->io_q.plugged > 0 || !unplug); |
| 211 | |
| 212 | if (unplug && --s->io_q.plugged > 0) { |
| 213 | return 0; |
| 214 | } |
| 215 | |
| 216 | if (s->io_q.idx > 0) { |
| 217 | ret = ioq_submit(s); |
| 218 | } |
| 219 | |
| 220 | return ret; |
| 221 | } |
| 222 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 223 | BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, |
| 224 | int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, |
| 225 | BlockDriverCompletionFunc *cb, void *opaque, int type) |
| 226 | { |
| 227 | struct qemu_laio_state *s = aio_ctx; |
| 228 | struct qemu_laiocb *laiocb; |
| 229 | struct iocb *iocbs; |
| 230 | off_t offset = sector_num * 512; |
| 231 | |
Stefan Hajnoczi | d7331be | 2012-10-31 16:34:37 +0100 | [diff] [blame] | 232 | laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 233 | laiocb->nbytes = nb_sectors * 512; |
| 234 | laiocb->ctx = s; |
| 235 | laiocb->ret = -EINPROGRESS; |
Kevin Wolf | b161e2e | 2011-10-13 15:42:52 +0200 | [diff] [blame] | 236 | laiocb->is_read = (type == QEMU_AIO_READ); |
| 237 | laiocb->qiov = qiov; |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 238 | |
| 239 | iocbs = &laiocb->iocb; |
| 240 | |
| 241 | switch (type) { |
| 242 | case QEMU_AIO_WRITE: |
| 243 | io_prep_pwritev(iocbs, fd, qiov->iov, qiov->niov, offset); |
| 244 | break; |
| 245 | case QEMU_AIO_READ: |
| 246 | io_prep_preadv(iocbs, fd, qiov->iov, qiov->niov, offset); |
| 247 | break; |
Frediano Ziglio | c30e624 | 2011-08-30 09:46:11 +0200 | [diff] [blame] | 248 | /* Currently Linux kernel does not support other operations */ |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 249 | default: |
| 250 | fprintf(stderr, "%s: invalid AIO request type 0x%x.\n", |
| 251 | __func__, type); |
| 252 | goto out_free_aiocb; |
| 253 | } |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 254 | io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e)); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 255 | |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 256 | if (!s->io_q.plugged) { |
| 257 | if (io_submit(s->ctx, 1, &iocbs) < 0) { |
| 258 | goto out_free_aiocb; |
| 259 | } |
| 260 | } else { |
| 261 | ioq_enqueue(s, iocbs); |
| 262 | } |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 263 | return &laiocb->common; |
| 264 | |
Kevin Wolf | 449c184 | 2011-09-22 14:21:30 +0200 | [diff] [blame] | 265 | out_free_aiocb: |
| 266 | qemu_aio_release(laiocb); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 267 | return NULL; |
| 268 | } |
| 269 | |
Stefan Hajnoczi | c2f3426 | 2014-05-08 16:34:47 +0200 | [diff] [blame] | 270 | void laio_detach_aio_context(void *s_, AioContext *old_context) |
| 271 | { |
| 272 | struct qemu_laio_state *s = s_; |
| 273 | |
| 274 | aio_set_event_notifier(old_context, &s->e, NULL); |
| 275 | } |
| 276 | |
| 277 | void laio_attach_aio_context(void *s_, AioContext *new_context) |
| 278 | { |
| 279 | struct qemu_laio_state *s = s_; |
| 280 | |
| 281 | aio_set_event_notifier(new_context, &s->e, qemu_laio_completion_cb); |
| 282 | } |
| 283 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 284 | void *laio_init(void) |
| 285 | { |
| 286 | struct qemu_laio_state *s; |
| 287 | |
Anthony Liguori | 7267c09 | 2011-08-20 22:09:37 -0500 | [diff] [blame] | 288 | s = g_malloc0(sizeof(*s)); |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 289 | if (event_notifier_init(&s->e, false) < 0) { |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 290 | goto out_free_state; |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 291 | } |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 292 | |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 293 | if (io_setup(MAX_EVENTS, &s->ctx) != 0) { |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 294 | goto out_close_efd; |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 295 | } |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 296 | |
Ming Lei | 1b3abdc | 2014-07-04 18:04:34 +0800 | [diff] [blame] | 297 | ioq_init(&s->io_q); |
| 298 | |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 299 | return s; |
| 300 | |
| 301 | out_close_efd: |
Paolo Bonzini | c90caf2 | 2012-02-24 08:39:02 +0100 | [diff] [blame] | 302 | event_notifier_cleanup(&s->e); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 303 | out_free_state: |
Anthony Liguori | 7267c09 | 2011-08-20 22:09:37 -0500 | [diff] [blame] | 304 | g_free(s); |
Christoph Hellwig | 5c6c3a6 | 2009-08-20 16:58:35 +0200 | [diff] [blame] | 305 | return NULL; |
| 306 | } |
Stefan Hajnoczi | abd269b | 2014-05-08 16:34:48 +0200 | [diff] [blame] | 307 | |
| 308 | void laio_cleanup(void *s_) |
| 309 | { |
| 310 | struct qemu_laio_state *s = s_; |
| 311 | |
| 312 | event_notifier_cleanup(&s->e); |
Gonglei | a1abf40 | 2014-07-12 11:43:37 +0800 | [diff] [blame^] | 313 | |
| 314 | if (io_destroy(s->ctx) != 0) { |
| 315 | fprintf(stderr, "%s: destroy AIO context %p failed\n", |
| 316 | __func__, &s->ctx); |
| 317 | } |
Stefan Hajnoczi | abd269b | 2014-05-08 16:34:48 +0200 | [diff] [blame] | 318 | g_free(s); |
| 319 | } |