1 #ifndef IO_URING_TYPES_H
2 #define IO_URING_TYPES_H
3
4 #include <linux/blkdev.h>
5 #include <linux/task_work.h>
6 #include <linux/bitmap.h>
7 #include <linux/llist.h>
8 #include <uapi/linux/io_uring.h>
9
10 struct io_wq_work_node {
11 struct io_wq_work_node *next;
12 };
13
14 struct io_wq_work_list {
15 struct io_wq_work_node *first;
16 struct io_wq_work_node *last;
17 };
18
19 struct io_wq_work {
20 struct io_wq_work_node list;
21 unsigned flags;
22 /* place it here instead of io_kiocb as it fills padding and saves 4B */
23 int cancel_seq;
24 };
25
26 struct io_fixed_file {
27 /* file * with additional FFS_* flags */
28 unsigned long file_ptr;
29 };
30
31 struct io_file_table {
32 struct io_fixed_file *files;
33 unsigned long *bitmap;
34 unsigned int alloc_hint;
35 };
36
37 struct io_hash_bucket {
38 spinlock_t lock;
39 struct hlist_head list;
40 } ____cacheline_aligned_in_smp;
41
42 struct io_hash_table {
43 struct io_hash_bucket *hbs;
44 unsigned hash_bits;
45 };
46
47 /*
48 * Arbitrary limit, can be raised if need be
49 */
50 #define IO_RINGFD_REG_MAX 16
51
52 struct io_uring_task {
53 /* submission side */
54 int cached_refs;
55 const struct io_ring_ctx *last;
56 struct io_wq *io_wq;
57 struct file *registered_rings[IO_RINGFD_REG_MAX];
58
59 struct xarray xa;
60 struct wait_queue_head wait;
61 atomic_t in_cancel;
62 atomic_t inflight_tracked;
63 struct percpu_counter inflight;
64
65 struct { /* task_work */
66 struct llist_head task_list;
67 struct callback_head task_work;
68 } ____cacheline_aligned_in_smp;
69 };
70
71 struct io_uring {
72 u32 head;
73 u32 tail;
74 };
75
76 /*
77 * This data is shared with the application through the mmap at offsets
78 * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
79 *
80 * The offsets to the member fields are published through struct
81 * io_sqring_offsets when calling io_uring_setup.
82 */
83 struct io_rings {
84 /*
85 * Head and tail offsets into the ring; the offsets need to be
86 * masked to get valid indices.
87 *
88 * The kernel controls head of the sq ring and the tail of the cq ring,
89 * and the application controls tail of the sq ring and the head of the
90 * cq ring.
91 */
92 struct io_uring sq, cq;
93 /*
94 * Bitmasks to apply to head and tail offsets (constant, equals
95 * ring_entries - 1)
96 */
97 u32 sq_ring_mask, cq_ring_mask;
98 /* Ring sizes (constant, power of 2) */
99 u32 sq_ring_entries, cq_ring_entries;
100 /*
101 * Number of invalid entries dropped by the kernel due to
102 * invalid index stored in array
103 *
104 * Written by the kernel, shouldn't be modified by the
105 * application (i.e. get number of "new events" by comparing to
106 * cached value).
107 *
108 * After a new SQ head value was read by the application this
109 * counter includes all submissions that were dropped reaching
110 * the new SQ head (and possibly more).
111 */
112 u32 sq_dropped;
113 /*
114 * Runtime SQ flags
115 *
116 * Written by the kernel, shouldn't be modified by the
117 * application.
118 *
119 * The application needs a full memory barrier before checking
120 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
121 */
122 atomic_t sq_flags;
123 /*
124 * Runtime CQ flags
125 *
126 * Written by the application, shouldn't be modified by the
127 * kernel.
128 */
129 u32 cq_flags;
130 /*
131 * Number of completion events lost because the queue was full;
132 * this should be avoided by the application by making sure
133 * there are not more requests pending than there is space in
134 * the completion queue.
135 *
136 * Written by the kernel, shouldn't be modified by the
137 * application (i.e. get number of "new events" by comparing to
138 * cached value).
139 *
140 * As completion events come in out of order this counter is not
141 * ordered with any other data.
142 */
143 u32 cq_overflow;
144 /*
145 * Ring buffer of completion events.
146 *
147 * The kernel writes completion events fresh every time they are
148 * produced, so the application is allowed to modify pending
149 * entries.
150 */
151 struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
152 };
153
154 struct io_restriction {
155 DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
156 DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
157 u8 sqe_flags_allowed;
158 u8 sqe_flags_required;
159 bool registered;
160 };
161
162 struct io_submit_link {
163 struct io_kiocb *head;
164 struct io_kiocb *last;
165 };
166
167 struct io_submit_state {
168 /* inline/task_work completion list, under ->uring_lock */
169 struct io_wq_work_node free_list;
170 /* batch completion logic */
171 struct io_wq_work_list compl_reqs;
172 struct io_submit_link link;
173
174 bool plug_started;
175 bool need_plug;
176 unsigned short submit_nr;
177 unsigned int cqes_count;
178 struct blk_plug plug;
179 };
180
181 struct io_ev_fd {
182 struct eventfd_ctx *cq_ev_fd;
183 unsigned int eventfd_async: 1;
184 struct rcu_head rcu;
185 atomic_t refs;
186 atomic_t ops;
187 };
188
189 struct io_alloc_cache {
190 struct io_wq_work_node list;
191 unsigned int nr_cached;
192 unsigned int max_cached;
193 size_t elem_size;
194 };
195
196 struct io_ring_ctx {
197 /* const or read-mostly hot data */
198 struct {
199 unsigned int flags;
200 unsigned int drain_next: 1;
201 unsigned int restricted: 1;
202 unsigned int off_timeout_used: 1;
203 unsigned int drain_active: 1;
204 unsigned int has_evfd: 1;
205 /* all CQEs should be posted only by the submitter task */
206 unsigned int task_complete: 1;
207 unsigned int lockless_cq: 1;
208 unsigned int syscall_iopoll: 1;
209 unsigned int poll_activated: 1;
210 unsigned int drain_disabled: 1;
211 unsigned int compat: 1;
212
213 struct task_struct *submitter_task;
214 struct io_rings *rings;
215 struct percpu_ref refs;
216
217 enum task_work_notify_mode notify_method;
218 } ____cacheline_aligned_in_smp;
219
220 /* submission data */
221 struct {
222 struct mutex uring_lock;
223
224 /*
225 * Ring buffer of indices into array of io_uring_sqe, which is
226 * mmapped by the application using the IORING_OFF_SQES offset.
227 *
228 * This indirection could e.g. be used to assign fixed
229 * io_uring_sqe entries to operations and only submit them to
230 * the queue when needed.
231 *
232 * The kernel modifies neither the indices array nor the entries
233 * array.
234 */
235 u32 *sq_array;
236 struct io_uring_sqe *sq_sqes;
237 unsigned cached_sq_head;
238 unsigned sq_entries;
239
240 /*
241 * Fixed resources fast path, should be accessed only under
242 * uring_lock, and updated through io_uring_register(2)
243 */
244 struct io_rsrc_node *rsrc_node;
245 atomic_t cancel_seq;
246 struct io_file_table file_table;
247 unsigned nr_user_files;
248 unsigned nr_user_bufs;
249 struct io_mapped_ubuf **user_bufs;
250
251 struct io_submit_state submit_state;
252
253 struct io_buffer_list *io_bl;
254 struct xarray io_bl_xa;
255
256 struct io_hash_table cancel_table_locked;
257 struct io_alloc_cache apoll_cache;
258 struct io_alloc_cache netmsg_cache;
259
260 /*
261 * ->iopoll_list is protected by the ctx->uring_lock for
262 * io_uring instances that don't use IORING_SETUP_SQPOLL.
263 * For SQPOLL, only the single threaded io_sq_thread() will
264 * manipulate the list, hence no extra locking is needed there.
265 */
266 struct io_wq_work_list iopoll_list;
267 bool poll_multi_queue;
268 } ____cacheline_aligned_in_smp;
269
270 struct {
271 /*
272 * We cache a range of free CQEs we can use, once exhausted it
273 * should go through a slower range setup, see __io_get_cqe()
274 */
275 struct io_uring_cqe *cqe_cached;
276 struct io_uring_cqe *cqe_sentinel;
277
278 unsigned cached_cq_tail;
279 unsigned cq_entries;
280 struct io_ev_fd __rcu *io_ev_fd;
281 unsigned cq_extra;
282 } ____cacheline_aligned_in_smp;
283
284 /*
285 * task_work and async notification delivery cacheline. Expected to
286 * regularly bounce b/w CPUs.
287 */
288 struct {
289 struct llist_head work_llist;
290 unsigned long check_cq;
291 atomic_t cq_wait_nr;
292 atomic_t cq_timeouts;
293 struct wait_queue_head cq_wait;
294 } ____cacheline_aligned_in_smp;
295
296 /* timeouts */
297 struct {
298 spinlock_t timeout_lock;
299 struct list_head timeout_list;
300 struct list_head ltimeout_list;
301 unsigned cq_last_tm_flush;
302 } ____cacheline_aligned_in_smp;
303
304 struct io_uring_cqe completion_cqes[16];
305
306 spinlock_t completion_lock;
307
308 /* IRQ completion list, under ->completion_lock */
309 struct io_wq_work_list locked_free_list;
310 unsigned int locked_free_nr;
311
312 struct list_head io_buffers_comp;
313 struct list_head cq_overflow_list;
314 struct io_hash_table cancel_table;
315
316 const struct cred *sq_creds; /* cred used for __io_sq_thread() */
317 struct io_sq_data *sq_data; /* if using sq thread polling */
318
319 struct wait_queue_head sqo_sq_wait;
320 struct list_head sqd_list;
321
322 unsigned int file_alloc_start;
323 unsigned int file_alloc_end;
324
325 struct xarray personalities;
326 u32 pers_next;
327
328 struct list_head io_buffers_cache;
329
330 /* deferred free list, protected by ->uring_lock */
331 struct hlist_head io_buf_list;
332
333 /* Keep this last, we don't need it for the fast path */
334 struct wait_queue_head poll_wq;
335 struct io_restriction restrictions;
336
337 /* slow path rsrc auxilary data, used by update/register */
338 struct io_mapped_ubuf *dummy_ubuf;
339 struct io_rsrc_data *file_data;
340 struct io_rsrc_data *buf_data;
341
342 /* protected by ->uring_lock */
343 struct list_head rsrc_ref_list;
344 struct io_alloc_cache rsrc_node_cache;
345 struct wait_queue_head rsrc_quiesce_wq;
346 unsigned rsrc_quiesce;
347
348 struct list_head io_buffers_pages;
349
350 #if defined(CONFIG_UNIX)
351 struct socket *ring_sock;
352 #endif
353 /* hashed buffered write serialization */
354 struct io_wq_hash *hash_map;
355
356 /* Only used for accounting purposes */
357 struct user_struct *user;
358 struct mm_struct *mm_account;
359
360 /* ctx exit and cancelation */
361 struct llist_head fallback_llist;
362 struct delayed_work fallback_work;
363 struct work_struct exit_work;
364 struct list_head tctx_list;
365 struct completion ref_comp;
366
367 /* io-wq management, e.g. thread count */
368 u32 iowq_limits[2];
369 bool iowq_limits_set;
370
371 struct callback_head poll_wq_task_work;
372 struct list_head defer_list;
373 unsigned sq_thread_idle;
374 /* protected by ->completion_lock */
375 unsigned evfd_last_cq_tail;
376
377 /*
378 * If IORING_SETUP_NO_MMAP is used, then the below holds
379 * the gup'ed pages for the two rings, and the sqes.
380 */
381 unsigned short n_ring_pages;
382 unsigned short n_sqe_pages;
383 struct page **ring_pages;
384 struct page **sqe_pages;
385 };
386
387 struct io_tw_state {
388 /* ->uring_lock is taken, callbacks can use io_tw_lock to lock it */
389 bool locked;
390 };
391
392 enum {
393 REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT,
394 REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT,
395 REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT,
396 REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT,
397 REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT,
398 REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
399 REQ_F_CQE_SKIP_BIT = IOSQE_CQE_SKIP_SUCCESS_BIT,
400
401 /* first byte is taken by user flags, shift it to not overlap */
402 REQ_F_FAIL_BIT = 8,
403 REQ_F_INFLIGHT_BIT,
404 REQ_F_CUR_POS_BIT,
405 REQ_F_NOWAIT_BIT,
406 REQ_F_LINK_TIMEOUT_BIT,
407 REQ_F_NEED_CLEANUP_BIT,
408 REQ_F_POLLED_BIT,
409 REQ_F_BUFFER_SELECTED_BIT,
410 REQ_F_BUFFER_RING_BIT,
411 REQ_F_REISSUE_BIT,
412 REQ_F_CREDS_BIT,
413 REQ_F_REFCOUNT_BIT,
414 REQ_F_ARM_LTIMEOUT_BIT,
415 REQ_F_ASYNC_DATA_BIT,
416 REQ_F_SKIP_LINK_CQES_BIT,
417 REQ_F_SINGLE_POLL_BIT,
418 REQ_F_DOUBLE_POLL_BIT,
419 REQ_F_PARTIAL_IO_BIT,
420 REQ_F_APOLL_MULTISHOT_BIT,
421 REQ_F_CLEAR_POLLIN_BIT,
422 REQ_F_HASH_LOCKED_BIT,
423 /* keep async read/write and isreg together and in order */
424 REQ_F_SUPPORT_NOWAIT_BIT,
425 REQ_F_ISREG_BIT,
426
427 /* not a real bit, just to check we're not overflowing the space */
428 __REQ_F_LAST_BIT,
429 };
430
431 enum {
432 /* ctx owns file */
433 REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT),
434 /* drain existing IO first */
435 REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT),
436 /* linked sqes */
437 REQ_F_LINK = BIT(REQ_F_LINK_BIT),
438 /* doesn't sever on completion < 0 */
439 REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT),
440 /* IOSQE_ASYNC */
441 REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT),
442 /* IOSQE_BUFFER_SELECT */
443 REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT),
444 /* IOSQE_CQE_SKIP_SUCCESS */
445 REQ_F_CQE_SKIP = BIT(REQ_F_CQE_SKIP_BIT),
446
447 /* fail rest of links */
448 REQ_F_FAIL = BIT(REQ_F_FAIL_BIT),
449 /* on inflight list, should be cancelled and waited on exit reliably */
450 REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT),
451 /* read/write uses file position */
452 REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT),
453 /* must not punt to workers */
454 REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT),
455 /* has or had linked timeout */
456 REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT),
457 /* needs cleanup */
458 REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
459 /* already went through poll handler */
460 REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
461 /* buffer already selected */
462 REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT),
463 /* buffer selected from ring, needs commit */
464 REQ_F_BUFFER_RING = BIT(REQ_F_BUFFER_RING_BIT),
465 /* caller should reissue async */
466 REQ_F_REISSUE = BIT(REQ_F_REISSUE_BIT),
467 /* supports async reads/writes */
468 REQ_F_SUPPORT_NOWAIT = BIT(REQ_F_SUPPORT_NOWAIT_BIT),
469 /* regular file */
470 REQ_F_ISREG = BIT(REQ_F_ISREG_BIT),
471 /* has creds assigned */
472 REQ_F_CREDS = BIT(REQ_F_CREDS_BIT),
473 /* skip refcounting if not set */
474 REQ_F_REFCOUNT = BIT(REQ_F_REFCOUNT_BIT),
475 /* there is a linked timeout that has to be armed */
476 REQ_F_ARM_LTIMEOUT = BIT(REQ_F_ARM_LTIMEOUT_BIT),
477 /* ->async_data allocated */
478 REQ_F_ASYNC_DATA = BIT(REQ_F_ASYNC_DATA_BIT),
479 /* don't post CQEs while failing linked requests */
480 REQ_F_SKIP_LINK_CQES = BIT(REQ_F_SKIP_LINK_CQES_BIT),
481 /* single poll may be active */
482 REQ_F_SINGLE_POLL = BIT(REQ_F_SINGLE_POLL_BIT),
483 /* double poll may active */
484 REQ_F_DOUBLE_POLL = BIT(REQ_F_DOUBLE_POLL_BIT),
485 /* request has already done partial IO */
486 REQ_F_PARTIAL_IO = BIT(REQ_F_PARTIAL_IO_BIT),
487 /* fast poll multishot mode */
488 REQ_F_APOLL_MULTISHOT = BIT(REQ_F_APOLL_MULTISHOT_BIT),
489 /* recvmsg special flag, clear EPOLLIN */
490 REQ_F_CLEAR_POLLIN = BIT(REQ_F_CLEAR_POLLIN_BIT),
491 /* hashed into ->cancel_hash_locked, protected by ->uring_lock */
492 REQ_F_HASH_LOCKED = BIT(REQ_F_HASH_LOCKED_BIT),
493 };
494
495 typedef void (*io_req_tw_func_t)(struct io_kiocb *req, struct io_tw_state *ts);
496
497 struct io_task_work {
498 struct llist_node node;
499 io_req_tw_func_t func;
500 };
501
502 struct io_cqe {
503 __u64 user_data;
504 __s32 res;
505 /* fd initially, then cflags for completion */
506 union {
507 __u32 flags;
508 int fd;
509 };
510 };
511
512 /*
513 * Each request type overlays its private data structure on top of this one.
514 * They must not exceed this one in size.
515 */
516 struct io_cmd_data {
517 struct file *file;
518 /* each command gets 56 bytes of data */
519 __u8 data[56];
520 };
521
io_kiocb_cmd_sz_check(size_t cmd_sz)522 static inline void io_kiocb_cmd_sz_check(size_t cmd_sz)
523 {
524 BUILD_BUG_ON(cmd_sz > sizeof(struct io_cmd_data));
525 }
526 #define io_kiocb_to_cmd(req, cmd_type) ( \
527 io_kiocb_cmd_sz_check(sizeof(cmd_type)) , \
528 ((cmd_type *)&(req)->cmd) \
529 )
530 #define cmd_to_io_kiocb(ptr) ((struct io_kiocb *) ptr)
531
532 struct io_kiocb {
533 union {
534 /*
535 * NOTE! Each of the io_kiocb union members has the file pointer
536 * as the first entry in their struct definition. So you can
537 * access the file pointer through any of the sub-structs,
538 * or directly as just 'file' in this struct.
539 */
540 struct file *file;
541 struct io_cmd_data cmd;
542 };
543
544 u8 opcode;
545 /* polled IO has completed */
546 u8 iopoll_completed;
547 /*
548 * Can be either a fixed buffer index, or used with provided buffers.
549 * For the latter, before issue it points to the buffer group ID,
550 * and after selection it points to the buffer ID itself.
551 */
552 u16 buf_index;
553 unsigned int flags;
554
555 struct io_cqe cqe;
556
557 struct io_ring_ctx *ctx;
558 struct task_struct *task;
559
560 struct io_rsrc_node *rsrc_node;
561
562 union {
563 /* store used ubuf, so we can prevent reloading */
564 struct io_mapped_ubuf *imu;
565
566 /* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */
567 struct io_buffer *kbuf;
568
569 /*
570 * stores buffer ID for ring provided buffers, valid IFF
571 * REQ_F_BUFFER_RING is set.
572 */
573 struct io_buffer_list *buf_list;
574 };
575
576 union {
577 /* used by request caches, completion batching and iopoll */
578 struct io_wq_work_node comp_list;
579 /* cache ->apoll->events */
580 __poll_t apoll_events;
581 };
582 atomic_t refs;
583 atomic_t poll_refs;
584 struct io_task_work io_task_work;
585 unsigned nr_tw;
586 /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
587 struct hlist_node hash_node;
588 /* internal polling, see IORING_FEAT_FAST_POLL */
589 struct async_poll *apoll;
590 /* opcode allocated if it needs to store data for async defer */
591 void *async_data;
592 /* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */
593 struct io_kiocb *link;
594 /* custom credentials, valid IFF REQ_F_CREDS is set */
595 const struct cred *creds;
596 struct io_wq_work work;
597
598 struct {
599 u64 extra1;
600 u64 extra2;
601 } big_cqe;
602 };
603
604 struct io_overflow_cqe {
605 struct list_head list;
606 struct io_uring_cqe cqe;
607 };
608
609 #endif
610