1  #ifndef IO_URING_TYPES_H
2  #define IO_URING_TYPES_H
3  
4  #include <linux/blkdev.h>
5  #include <linux/hashtable.h>
6  #include <linux/task_work.h>
7  #include <linux/bitmap.h>
8  #include <linux/llist.h>
9  #include <uapi/linux/io_uring.h>
10  
11  enum {
12  	/*
13  	 * A hint to not wake right away but delay until there are enough of
14  	 * tw's queued to match the number of CQEs the task is waiting for.
15  	 *
16  	 * Must not be used with requests generating more than one CQE.
17  	 * It's also ignored unless IORING_SETUP_DEFER_TASKRUN is set.
18  	 */
19  	IOU_F_TWQ_LAZY_WAKE			= 1,
20  };
21  
22  enum io_uring_cmd_flags {
23  	IO_URING_F_COMPLETE_DEFER	= 1,
24  	IO_URING_F_UNLOCKED		= 2,
25  	/* the request is executed from poll, it should not be freed */
26  	IO_URING_F_MULTISHOT		= 4,
27  	/* executed by io-wq */
28  	IO_URING_F_IOWQ			= 8,
29  	/* int's last bit, sign checks are usually faster than a bit test */
30  	IO_URING_F_NONBLOCK		= INT_MIN,
31  
32  	/* ctx state flags, for URING_CMD */
33  	IO_URING_F_SQE128		= (1 << 8),
34  	IO_URING_F_CQE32		= (1 << 9),
35  	IO_URING_F_IOPOLL		= (1 << 10),
36  
37  	/* set when uring wants to cancel a previously issued command */
38  	IO_URING_F_CANCEL		= (1 << 11),
39  	IO_URING_F_COMPAT		= (1 << 12),
40  };
41  
42  struct io_wq_work_node {
43  	struct io_wq_work_node *next;
44  };
45  
46  struct io_wq_work_list {
47  	struct io_wq_work_node *first;
48  	struct io_wq_work_node *last;
49  };
50  
51  struct io_wq_work {
52  	struct io_wq_work_node list;
53  	atomic_t flags;
54  	/* place it here instead of io_kiocb as it fills padding and saves 4B */
55  	int cancel_seq;
56  };
57  
58  struct io_fixed_file {
59  	/* file * with additional FFS_* flags */
60  	unsigned long file_ptr;
61  };
62  
63  struct io_file_table {
64  	struct io_fixed_file *files;
65  	unsigned long *bitmap;
66  	unsigned int alloc_hint;
67  };
68  
69  struct io_hash_bucket {
70  	spinlock_t		lock;
71  	struct hlist_head	list;
72  } ____cacheline_aligned_in_smp;
73  
74  struct io_hash_table {
75  	struct io_hash_bucket	*hbs;
76  	unsigned		hash_bits;
77  };
78  
79  /*
80   * Arbitrary limit, can be raised if need be
81   */
82  #define IO_RINGFD_REG_MAX 16
83  
84  struct io_uring_task {
85  	/* submission side */
86  	int				cached_refs;
87  	const struct io_ring_ctx 	*last;
88  	struct io_wq			*io_wq;
89  	struct file			*registered_rings[IO_RINGFD_REG_MAX];
90  
91  	struct xarray			xa;
92  	struct wait_queue_head		wait;
93  	atomic_t			in_cancel;
94  	atomic_t			inflight_tracked;
95  	struct percpu_counter		inflight;
96  
97  	struct { /* task_work */
98  		struct llist_head	task_list;
99  		struct callback_head	task_work;
100  	} ____cacheline_aligned_in_smp;
101  };
102  
103  struct io_uring {
104  	u32 head;
105  	u32 tail;
106  };
107  
108  /*
109   * This data is shared with the application through the mmap at offsets
110   * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
111   *
112   * The offsets to the member fields are published through struct
113   * io_sqring_offsets when calling io_uring_setup.
114   */
115  struct io_rings {
116  	/*
117  	 * Head and tail offsets into the ring; the offsets need to be
118  	 * masked to get valid indices.
119  	 *
120  	 * The kernel controls head of the sq ring and the tail of the cq ring,
121  	 * and the application controls tail of the sq ring and the head of the
122  	 * cq ring.
123  	 */
124  	struct io_uring		sq, cq;
125  	/*
126  	 * Bitmasks to apply to head and tail offsets (constant, equals
127  	 * ring_entries - 1)
128  	 */
129  	u32			sq_ring_mask, cq_ring_mask;
130  	/* Ring sizes (constant, power of 2) */
131  	u32			sq_ring_entries, cq_ring_entries;
132  	/*
133  	 * Number of invalid entries dropped by the kernel due to
134  	 * invalid index stored in array
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  	 * After a new SQ head value was read by the application this
141  	 * counter includes all submissions that were dropped reaching
142  	 * the new SQ head (and possibly more).
143  	 */
144  	u32			sq_dropped;
145  	/*
146  	 * Runtime SQ flags
147  	 *
148  	 * Written by the kernel, shouldn't be modified by the
149  	 * application.
150  	 *
151  	 * The application needs a full memory barrier before checking
152  	 * for IORING_SQ_NEED_WAKEUP after updating the sq tail.
153  	 */
154  	atomic_t		sq_flags;
155  	/*
156  	 * Runtime CQ flags
157  	 *
158  	 * Written by the application, shouldn't be modified by the
159  	 * kernel.
160  	 */
161  	u32			cq_flags;
162  	/*
163  	 * Number of completion events lost because the queue was full;
164  	 * this should be avoided by the application by making sure
165  	 * there are not more requests pending than there is space in
166  	 * the completion queue.
167  	 *
168  	 * Written by the kernel, shouldn't be modified by the
169  	 * application (i.e. get number of "new events" by comparing to
170  	 * cached value).
171  	 *
172  	 * As completion events come in out of order this counter is not
173  	 * ordered with any other data.
174  	 */
175  	u32			cq_overflow;
176  	/*
177  	 * Ring buffer of completion events.
178  	 *
179  	 * The kernel writes completion events fresh every time they are
180  	 * produced, so the application is allowed to modify pending
181  	 * entries.
182  	 */
183  	struct io_uring_cqe	cqes[] ____cacheline_aligned_in_smp;
184  };
185  
186  struct io_restriction {
187  	DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
188  	DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
189  	u8 sqe_flags_allowed;
190  	u8 sqe_flags_required;
191  	bool registered;
192  };
193  
194  struct io_submit_link {
195  	struct io_kiocb		*head;
196  	struct io_kiocb		*last;
197  };
198  
199  struct io_submit_state {
200  	/* inline/task_work completion list, under ->uring_lock */
201  	struct io_wq_work_node	free_list;
202  	/* batch completion logic */
203  	struct io_wq_work_list	compl_reqs;
204  	struct io_submit_link	link;
205  
206  	bool			plug_started;
207  	bool			need_plug;
208  	bool			cq_flush;
209  	unsigned short		submit_nr;
210  	struct blk_plug		plug;
211  };
212  
213  struct io_alloc_cache {
214  	void			**entries;
215  	unsigned int		nr_cached;
216  	unsigned int		max_cached;
217  	size_t			elem_size;
218  };
219  
220  struct io_ring_ctx {
221  	/* const or read-mostly hot data */
222  	struct {
223  		unsigned int		flags;
224  		unsigned int		drain_next: 1;
225  		unsigned int		restricted: 1;
226  		unsigned int		off_timeout_used: 1;
227  		unsigned int		drain_active: 1;
228  		unsigned int		has_evfd: 1;
229  		/* all CQEs should be posted only by the submitter task */
230  		unsigned int		task_complete: 1;
231  		unsigned int		lockless_cq: 1;
232  		unsigned int		syscall_iopoll: 1;
233  		unsigned int		poll_activated: 1;
234  		unsigned int		drain_disabled: 1;
235  		unsigned int		compat: 1;
236  		unsigned int		iowq_limits_set : 1;
237  
238  		struct task_struct	*submitter_task;
239  		struct io_rings		*rings;
240  		struct percpu_ref	refs;
241  
242  		clockid_t		clockid;
243  		enum tk_offsets		clock_offset;
244  
245  		enum task_work_notify_mode	notify_method;
246  		unsigned			sq_thread_idle;
247  	} ____cacheline_aligned_in_smp;
248  
249  	/* submission data */
250  	struct {
251  		struct mutex		uring_lock;
252  
253  		/*
254  		 * Ring buffer of indices into array of io_uring_sqe, which is
255  		 * mmapped by the application using the IORING_OFF_SQES offset.
256  		 *
257  		 * This indirection could e.g. be used to assign fixed
258  		 * io_uring_sqe entries to operations and only submit them to
259  		 * the queue when needed.
260  		 *
261  		 * The kernel modifies neither the indices array nor the entries
262  		 * array.
263  		 */
264  		u32			*sq_array;
265  		struct io_uring_sqe	*sq_sqes;
266  		unsigned		cached_sq_head;
267  		unsigned		sq_entries;
268  
269  		/*
270  		 * Fixed resources fast path, should be accessed only under
271  		 * uring_lock, and updated through io_uring_register(2)
272  		 */
273  		struct io_rsrc_node	*rsrc_node;
274  		atomic_t		cancel_seq;
275  
276  		/*
277  		 * ->iopoll_list is protected by the ctx->uring_lock for
278  		 * io_uring instances that don't use IORING_SETUP_SQPOLL.
279  		 * For SQPOLL, only the single threaded io_sq_thread() will
280  		 * manipulate the list, hence no extra locking is needed there.
281  		 */
282  		bool			poll_multi_queue;
283  		struct io_wq_work_list	iopoll_list;
284  
285  		struct io_file_table	file_table;
286  		struct io_mapped_ubuf	**user_bufs;
287  		unsigned		nr_user_files;
288  		unsigned		nr_user_bufs;
289  
290  		struct io_submit_state	submit_state;
291  
292  		struct xarray		io_bl_xa;
293  
294  		struct io_hash_table	cancel_table_locked;
295  		struct io_alloc_cache	apoll_cache;
296  		struct io_alloc_cache	netmsg_cache;
297  		struct io_alloc_cache	rw_cache;
298  		struct io_alloc_cache	uring_cache;
299  
300  		/*
301  		 * Any cancelable uring_cmd is added to this list in
302  		 * ->uring_cmd() by io_uring_cmd_insert_cancelable()
303  		 */
304  		struct hlist_head	cancelable_uring_cmd;
305  	} ____cacheline_aligned_in_smp;
306  
307  	struct {
308  		/*
309  		 * We cache a range of free CQEs we can use, once exhausted it
310  		 * should go through a slower range setup, see __io_get_cqe()
311  		 */
312  		struct io_uring_cqe	*cqe_cached;
313  		struct io_uring_cqe	*cqe_sentinel;
314  
315  		unsigned		cached_cq_tail;
316  		unsigned		cq_entries;
317  		struct io_ev_fd	__rcu	*io_ev_fd;
318  		unsigned		cq_extra;
319  	} ____cacheline_aligned_in_smp;
320  
321  	/*
322  	 * task_work and async notification delivery cacheline. Expected to
323  	 * regularly bounce b/w CPUs.
324  	 */
325  	struct {
326  		struct llist_head	work_llist;
327  		unsigned long		check_cq;
328  		atomic_t		cq_wait_nr;
329  		atomic_t		cq_timeouts;
330  		struct wait_queue_head	cq_wait;
331  	} ____cacheline_aligned_in_smp;
332  
333  	/* timeouts */
334  	struct {
335  		spinlock_t		timeout_lock;
336  		struct list_head	timeout_list;
337  		struct list_head	ltimeout_list;
338  		unsigned		cq_last_tm_flush;
339  	} ____cacheline_aligned_in_smp;
340  
341  	spinlock_t		completion_lock;
342  
343  	struct list_head	io_buffers_comp;
344  	struct list_head	cq_overflow_list;
345  	struct io_hash_table	cancel_table;
346  
347  	struct hlist_head	waitid_list;
348  
349  #ifdef CONFIG_FUTEX
350  	struct hlist_head	futex_list;
351  	struct io_alloc_cache	futex_cache;
352  #endif
353  
354  	const struct cred	*sq_creds;	/* cred used for __io_sq_thread() */
355  	struct io_sq_data	*sq_data;	/* if using sq thread polling */
356  
357  	struct wait_queue_head	sqo_sq_wait;
358  	struct list_head	sqd_list;
359  
360  	unsigned int		file_alloc_start;
361  	unsigned int		file_alloc_end;
362  
363  	struct list_head	io_buffers_cache;
364  
365  	/* Keep this last, we don't need it for the fast path */
366  	struct wait_queue_head		poll_wq;
367  	struct io_restriction		restrictions;
368  
369  	/* slow path rsrc auxilary data, used by update/register */
370  	struct io_rsrc_data		*file_data;
371  	struct io_rsrc_data		*buf_data;
372  
373  	/* protected by ->uring_lock */
374  	struct list_head		rsrc_ref_list;
375  	struct io_alloc_cache		rsrc_node_cache;
376  	struct wait_queue_head		rsrc_quiesce_wq;
377  	unsigned			rsrc_quiesce;
378  
379  	u32			pers_next;
380  	struct xarray		personalities;
381  
382  	/* hashed buffered write serialization */
383  	struct io_wq_hash		*hash_map;
384  
385  	/* Only used for accounting purposes */
386  	struct user_struct		*user;
387  	struct mm_struct		*mm_account;
388  
389  	/* ctx exit and cancelation */
390  	struct llist_head		fallback_llist;
391  	struct delayed_work		fallback_work;
392  	struct work_struct		exit_work;
393  	struct list_head		tctx_list;
394  	struct completion		ref_comp;
395  
396  	/* io-wq management, e.g. thread count */
397  	u32				iowq_limits[2];
398  
399  	struct callback_head		poll_wq_task_work;
400  	struct list_head		defer_list;
401  
402  	struct io_alloc_cache		msg_cache;
403  	spinlock_t			msg_lock;
404  
405  #ifdef CONFIG_NET_RX_BUSY_POLL
406  	struct list_head	napi_list;	/* track busy poll napi_id */
407  	spinlock_t		napi_lock;	/* napi_list lock */
408  
409  	/* napi busy poll default timeout */
410  	ktime_t			napi_busy_poll_dt;
411  	bool			napi_prefer_busy_poll;
412  	bool			napi_enabled;
413  
414  	DECLARE_HASHTABLE(napi_ht, 4);
415  #endif
416  
417  	/* protected by ->completion_lock */
418  	unsigned			evfd_last_cq_tail;
419  
420  	/*
421  	 * If IORING_SETUP_NO_MMAP is used, then the below holds
422  	 * the gup'ed pages for the two rings, and the sqes.
423  	 */
424  	unsigned short			n_ring_pages;
425  	unsigned short			n_sqe_pages;
426  	struct page			**ring_pages;
427  	struct page			**sqe_pages;
428  };
429  
430  struct io_tw_state {
431  };
432  
433  enum {
434  	REQ_F_FIXED_FILE_BIT	= IOSQE_FIXED_FILE_BIT,
435  	REQ_F_IO_DRAIN_BIT	= IOSQE_IO_DRAIN_BIT,
436  	REQ_F_LINK_BIT		= IOSQE_IO_LINK_BIT,
437  	REQ_F_HARDLINK_BIT	= IOSQE_IO_HARDLINK_BIT,
438  	REQ_F_FORCE_ASYNC_BIT	= IOSQE_ASYNC_BIT,
439  	REQ_F_BUFFER_SELECT_BIT	= IOSQE_BUFFER_SELECT_BIT,
440  	REQ_F_CQE_SKIP_BIT	= IOSQE_CQE_SKIP_SUCCESS_BIT,
441  
442  	/* first byte is taken by user flags, shift it to not overlap */
443  	REQ_F_FAIL_BIT		= 8,
444  	REQ_F_INFLIGHT_BIT,
445  	REQ_F_CUR_POS_BIT,
446  	REQ_F_NOWAIT_BIT,
447  	REQ_F_LINK_TIMEOUT_BIT,
448  	REQ_F_NEED_CLEANUP_BIT,
449  	REQ_F_POLLED_BIT,
450  	REQ_F_BUFFER_SELECTED_BIT,
451  	REQ_F_BUFFER_RING_BIT,
452  	REQ_F_REISSUE_BIT,
453  	REQ_F_CREDS_BIT,
454  	REQ_F_REFCOUNT_BIT,
455  	REQ_F_ARM_LTIMEOUT_BIT,
456  	REQ_F_ASYNC_DATA_BIT,
457  	REQ_F_SKIP_LINK_CQES_BIT,
458  	REQ_F_SINGLE_POLL_BIT,
459  	REQ_F_DOUBLE_POLL_BIT,
460  	REQ_F_APOLL_MULTISHOT_BIT,
461  	REQ_F_CLEAR_POLLIN_BIT,
462  	REQ_F_HASH_LOCKED_BIT,
463  	/* keep async read/write and isreg together and in order */
464  	REQ_F_SUPPORT_NOWAIT_BIT,
465  	REQ_F_ISREG_BIT,
466  	REQ_F_POLL_NO_LAZY_BIT,
467  	REQ_F_CAN_POLL_BIT,
468  	REQ_F_BL_EMPTY_BIT,
469  	REQ_F_BL_NO_RECYCLE_BIT,
470  	REQ_F_BUFFERS_COMMIT_BIT,
471  
472  	/* not a real bit, just to check we're not overflowing the space */
473  	__REQ_F_LAST_BIT,
474  };
475  
476  typedef u64 __bitwise io_req_flags_t;
477  #define IO_REQ_FLAG(bitno)	((__force io_req_flags_t) BIT_ULL((bitno)))
478  
479  enum {
480  	/* ctx owns file */
481  	REQ_F_FIXED_FILE	= IO_REQ_FLAG(REQ_F_FIXED_FILE_BIT),
482  	/* drain existing IO first */
483  	REQ_F_IO_DRAIN		= IO_REQ_FLAG(REQ_F_IO_DRAIN_BIT),
484  	/* linked sqes */
485  	REQ_F_LINK		= IO_REQ_FLAG(REQ_F_LINK_BIT),
486  	/* doesn't sever on completion < 0 */
487  	REQ_F_HARDLINK		= IO_REQ_FLAG(REQ_F_HARDLINK_BIT),
488  	/* IOSQE_ASYNC */
489  	REQ_F_FORCE_ASYNC	= IO_REQ_FLAG(REQ_F_FORCE_ASYNC_BIT),
490  	/* IOSQE_BUFFER_SELECT */
491  	REQ_F_BUFFER_SELECT	= IO_REQ_FLAG(REQ_F_BUFFER_SELECT_BIT),
492  	/* IOSQE_CQE_SKIP_SUCCESS */
493  	REQ_F_CQE_SKIP		= IO_REQ_FLAG(REQ_F_CQE_SKIP_BIT),
494  
495  	/* fail rest of links */
496  	REQ_F_FAIL		= IO_REQ_FLAG(REQ_F_FAIL_BIT),
497  	/* on inflight list, should be cancelled and waited on exit reliably */
498  	REQ_F_INFLIGHT		= IO_REQ_FLAG(REQ_F_INFLIGHT_BIT),
499  	/* read/write uses file position */
500  	REQ_F_CUR_POS		= IO_REQ_FLAG(REQ_F_CUR_POS_BIT),
501  	/* must not punt to workers */
502  	REQ_F_NOWAIT		= IO_REQ_FLAG(REQ_F_NOWAIT_BIT),
503  	/* has or had linked timeout */
504  	REQ_F_LINK_TIMEOUT	= IO_REQ_FLAG(REQ_F_LINK_TIMEOUT_BIT),
505  	/* needs cleanup */
506  	REQ_F_NEED_CLEANUP	= IO_REQ_FLAG(REQ_F_NEED_CLEANUP_BIT),
507  	/* already went through poll handler */
508  	REQ_F_POLLED		= IO_REQ_FLAG(REQ_F_POLLED_BIT),
509  	/* buffer already selected */
510  	REQ_F_BUFFER_SELECTED	= IO_REQ_FLAG(REQ_F_BUFFER_SELECTED_BIT),
511  	/* buffer selected from ring, needs commit */
512  	REQ_F_BUFFER_RING	= IO_REQ_FLAG(REQ_F_BUFFER_RING_BIT),
513  	/* caller should reissue async */
514  	REQ_F_REISSUE		= IO_REQ_FLAG(REQ_F_REISSUE_BIT),
515  	/* supports async reads/writes */
516  	REQ_F_SUPPORT_NOWAIT	= IO_REQ_FLAG(REQ_F_SUPPORT_NOWAIT_BIT),
517  	/* regular file */
518  	REQ_F_ISREG		= IO_REQ_FLAG(REQ_F_ISREG_BIT),
519  	/* has creds assigned */
520  	REQ_F_CREDS		= IO_REQ_FLAG(REQ_F_CREDS_BIT),
521  	/* skip refcounting if not set */
522  	REQ_F_REFCOUNT		= IO_REQ_FLAG(REQ_F_REFCOUNT_BIT),
523  	/* there is a linked timeout that has to be armed */
524  	REQ_F_ARM_LTIMEOUT	= IO_REQ_FLAG(REQ_F_ARM_LTIMEOUT_BIT),
525  	/* ->async_data allocated */
526  	REQ_F_ASYNC_DATA	= IO_REQ_FLAG(REQ_F_ASYNC_DATA_BIT),
527  	/* don't post CQEs while failing linked requests */
528  	REQ_F_SKIP_LINK_CQES	= IO_REQ_FLAG(REQ_F_SKIP_LINK_CQES_BIT),
529  	/* single poll may be active */
530  	REQ_F_SINGLE_POLL	= IO_REQ_FLAG(REQ_F_SINGLE_POLL_BIT),
531  	/* double poll may active */
532  	REQ_F_DOUBLE_POLL	= IO_REQ_FLAG(REQ_F_DOUBLE_POLL_BIT),
533  	/* fast poll multishot mode */
534  	REQ_F_APOLL_MULTISHOT	= IO_REQ_FLAG(REQ_F_APOLL_MULTISHOT_BIT),
535  	/* recvmsg special flag, clear EPOLLIN */
536  	REQ_F_CLEAR_POLLIN	= IO_REQ_FLAG(REQ_F_CLEAR_POLLIN_BIT),
537  	/* hashed into ->cancel_hash_locked, protected by ->uring_lock */
538  	REQ_F_HASH_LOCKED	= IO_REQ_FLAG(REQ_F_HASH_LOCKED_BIT),
539  	/* don't use lazy poll wake for this request */
540  	REQ_F_POLL_NO_LAZY	= IO_REQ_FLAG(REQ_F_POLL_NO_LAZY_BIT),
541  	/* file is pollable */
542  	REQ_F_CAN_POLL		= IO_REQ_FLAG(REQ_F_CAN_POLL_BIT),
543  	/* buffer list was empty after selection of buffer */
544  	REQ_F_BL_EMPTY		= IO_REQ_FLAG(REQ_F_BL_EMPTY_BIT),
545  	/* don't recycle provided buffers for this request */
546  	REQ_F_BL_NO_RECYCLE	= IO_REQ_FLAG(REQ_F_BL_NO_RECYCLE_BIT),
547  	/* buffer ring head needs incrementing on put */
548  	REQ_F_BUFFERS_COMMIT	= IO_REQ_FLAG(REQ_F_BUFFERS_COMMIT_BIT),
549  };
550  
551  typedef void (*io_req_tw_func_t)(struct io_kiocb *req, struct io_tw_state *ts);
552  
553  struct io_task_work {
554  	struct llist_node		node;
555  	io_req_tw_func_t		func;
556  };
557  
558  struct io_cqe {
559  	__u64	user_data;
560  	__s32	res;
561  	/* fd initially, then cflags for completion */
562  	union {
563  		__u32	flags;
564  		int	fd;
565  	};
566  };
567  
568  /*
569   * Each request type overlays its private data structure on top of this one.
570   * They must not exceed this one in size.
571   */
572  struct io_cmd_data {
573  	struct file		*file;
574  	/* each command gets 56 bytes of data */
575  	__u8			data[56];
576  };
577  
io_kiocb_cmd_sz_check(size_t cmd_sz)578  static inline void io_kiocb_cmd_sz_check(size_t cmd_sz)
579  {
580  	BUILD_BUG_ON(cmd_sz > sizeof(struct io_cmd_data));
581  }
582  #define io_kiocb_to_cmd(req, cmd_type) ( \
583  	io_kiocb_cmd_sz_check(sizeof(cmd_type)) , \
584  	((cmd_type *)&(req)->cmd) \
585  )
586  #define cmd_to_io_kiocb(ptr)	((struct io_kiocb *) ptr)
587  
588  struct io_kiocb {
589  	union {
590  		/*
591  		 * NOTE! Each of the io_kiocb union members has the file pointer
592  		 * as the first entry in their struct definition. So you can
593  		 * access the file pointer through any of the sub-structs,
594  		 * or directly as just 'file' in this struct.
595  		 */
596  		struct file		*file;
597  		struct io_cmd_data	cmd;
598  	};
599  
600  	u8				opcode;
601  	/* polled IO has completed */
602  	u8				iopoll_completed;
603  	/*
604  	 * Can be either a fixed buffer index, or used with provided buffers.
605  	 * For the latter, before issue it points to the buffer group ID,
606  	 * and after selection it points to the buffer ID itself.
607  	 */
608  	u16				buf_index;
609  
610  	unsigned			nr_tw;
611  
612  	/* REQ_F_* flags */
613  	io_req_flags_t			flags;
614  
615  	struct io_cqe			cqe;
616  
617  	struct io_ring_ctx		*ctx;
618  	struct task_struct		*task;
619  
620  	union {
621  		/* store used ubuf, so we can prevent reloading */
622  		struct io_mapped_ubuf	*imu;
623  
624  		/* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */
625  		struct io_buffer	*kbuf;
626  
627  		/*
628  		 * stores buffer ID for ring provided buffers, valid IFF
629  		 * REQ_F_BUFFER_RING is set.
630  		 */
631  		struct io_buffer_list	*buf_list;
632  	};
633  
634  	union {
635  		/* used by request caches, completion batching and iopoll */
636  		struct io_wq_work_node	comp_list;
637  		/* cache ->apoll->events */
638  		__poll_t apoll_events;
639  	};
640  
641  	struct io_rsrc_node		*rsrc_node;
642  
643  	atomic_t			refs;
644  	bool				cancel_seq_set;
645  	struct io_task_work		io_task_work;
646  	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
647  	struct hlist_node		hash_node;
648  	/* internal polling, see IORING_FEAT_FAST_POLL */
649  	struct async_poll		*apoll;
650  	/* opcode allocated if it needs to store data for async defer */
651  	void				*async_data;
652  	/* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */
653  	atomic_t			poll_refs;
654  	struct io_kiocb			*link;
655  	/* custom credentials, valid IFF REQ_F_CREDS is set */
656  	const struct cred		*creds;
657  	struct io_wq_work		work;
658  
659  	struct {
660  		u64			extra1;
661  		u64			extra2;
662  	} big_cqe;
663  };
664  
665  struct io_overflow_cqe {
666  	struct list_head list;
667  	struct io_uring_cqe cqe;
668  };
669  
670  #endif
671