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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
5dd43ce2 IM |
2 | #ifndef _LINUX_WAIT_BIT_H |
3 | #define _LINUX_WAIT_BIT_H | |
4 | ||
5 | /* | |
6 | * Linux wait-bit related types and methods: | |
7 | */ | |
8 | #include <linux/wait.h> | |
9 | ||
10 | struct wait_bit_key { | |
11 | void *flags; | |
12 | int bit_nr; | |
5dd43ce2 IM |
13 | unsigned long timeout; |
14 | }; | |
15 | ||
16 | struct wait_bit_queue_entry { | |
17 | struct wait_bit_key key; | |
18 | struct wait_queue_entry wq_entry; | |
19 | }; | |
20 | ||
21 | #define __WAIT_BIT_KEY_INITIALIZER(word, bit) \ | |
22 | { .flags = word, .bit_nr = bit, } | |
23 | ||
5dd43ce2 | 24 | typedef int wait_bit_action_f(struct wait_bit_key *key, int mode); |
5e4def20 | 25 | |
5dd43ce2 IM |
26 | void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit); |
27 | int __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode); | |
28 | int __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode); | |
29 | void wake_up_bit(void *word, int bit); | |
5dd43ce2 IM |
30 | int out_of_line_wait_on_bit(void *word, int, wait_bit_action_f *action, unsigned int mode); |
31 | int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout); | |
32 | int out_of_line_wait_on_bit_lock(void *word, int, wait_bit_action_f *action, unsigned int mode); | |
5dd43ce2 | 33 | struct wait_queue_head *bit_waitqueue(void *word, int bit); |
5822a454 | 34 | extern void __init wait_bit_init(void); |
5dd43ce2 IM |
35 | |
36 | int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); | |
37 | ||
38 | #define DEFINE_WAIT_BIT(name, word, bit) \ | |
39 | struct wait_bit_queue_entry name = { \ | |
40 | .key = __WAIT_BIT_KEY_INITIALIZER(word, bit), \ | |
41 | .wq_entry = { \ | |
42 | .private = current, \ | |
43 | .func = wake_bit_function, \ | |
2055da97 IM |
44 | .entry = \ |
45 | LIST_HEAD_INIT((name).wq_entry.entry), \ | |
5dd43ce2 IM |
46 | }, \ |
47 | } | |
48 | ||
5e4def20 DH |
49 | extern int bit_wait(struct wait_bit_key *key, int mode); |
50 | extern int bit_wait_io(struct wait_bit_key *key, int mode); | |
51 | extern int bit_wait_timeout(struct wait_bit_key *key, int mode); | |
52 | extern int bit_wait_io_timeout(struct wait_bit_key *key, int mode); | |
5dd43ce2 IM |
53 | |
54 | /** | |
55 | * wait_on_bit - wait for a bit to be cleared | |
56 | * @word: the word being waited on, a kernel virtual address | |
57 | * @bit: the bit of the word being waited on | |
58 | * @mode: the task state to sleep in | |
59 | * | |
60 | * There is a standard hashed waitqueue table for generic use. This | |
61 | * is the part of the hashtable's accessor API that waits on a bit. | |
62 | * For instance, if one were to have waiters on a bitflag, one would | |
63 | * call wait_on_bit() in threads waiting for the bit to clear. | |
64 | * One uses wait_on_bit() where one is waiting for the bit to clear, | |
65 | * but has no intention of setting it. | |
66 | * Returned value will be zero if the bit was cleared, or non-zero | |
67 | * if the process received a signal and the mode permitted wakeup | |
68 | * on that signal. | |
69 | */ | |
70 | static inline int | |
71 | wait_on_bit(unsigned long *word, int bit, unsigned mode) | |
72 | { | |
73 | might_sleep(); | |
8238b457 | 74 | if (!test_bit_acquire(bit, word)) |
5dd43ce2 IM |
75 | return 0; |
76 | return out_of_line_wait_on_bit(word, bit, | |
77 | bit_wait, | |
78 | mode); | |
79 | } | |
80 | ||
81 | /** | |
82 | * wait_on_bit_io - wait for a bit to be cleared | |
83 | * @word: the word being waited on, a kernel virtual address | |
84 | * @bit: the bit of the word being waited on | |
85 | * @mode: the task state to sleep in | |
86 | * | |
87 | * Use the standard hashed waitqueue table to wait for a bit | |
88 | * to be cleared. This is similar to wait_on_bit(), but calls | |
89 | * io_schedule() instead of schedule() for the actual waiting. | |
90 | * | |
91 | * Returned value will be zero if the bit was cleared, or non-zero | |
92 | * if the process received a signal and the mode permitted wakeup | |
93 | * on that signal. | |
94 | */ | |
95 | static inline int | |
96 | wait_on_bit_io(unsigned long *word, int bit, unsigned mode) | |
97 | { | |
98 | might_sleep(); | |
8238b457 | 99 | if (!test_bit_acquire(bit, word)) |
5dd43ce2 IM |
100 | return 0; |
101 | return out_of_line_wait_on_bit(word, bit, | |
102 | bit_wait_io, | |
103 | mode); | |
104 | } | |
105 | ||
106 | /** | |
107 | * wait_on_bit_timeout - wait for a bit to be cleared or a timeout elapses | |
108 | * @word: the word being waited on, a kernel virtual address | |
109 | * @bit: the bit of the word being waited on | |
110 | * @mode: the task state to sleep in | |
111 | * @timeout: timeout, in jiffies | |
112 | * | |
113 | * Use the standard hashed waitqueue table to wait for a bit | |
114 | * to be cleared. This is similar to wait_on_bit(), except also takes a | |
115 | * timeout parameter. | |
116 | * | |
117 | * Returned value will be zero if the bit was cleared before the | |
118 | * @timeout elapsed, or non-zero if the @timeout elapsed or process | |
119 | * received a signal and the mode permitted wakeup on that signal. | |
120 | */ | |
121 | static inline int | |
122 | wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode, | |
123 | unsigned long timeout) | |
124 | { | |
125 | might_sleep(); | |
8238b457 | 126 | if (!test_bit_acquire(bit, word)) |
5dd43ce2 IM |
127 | return 0; |
128 | return out_of_line_wait_on_bit_timeout(word, bit, | |
129 | bit_wait_timeout, | |
130 | mode, timeout); | |
131 | } | |
132 | ||
133 | /** | |
134 | * wait_on_bit_action - wait for a bit to be cleared | |
135 | * @word: the word being waited on, a kernel virtual address | |
136 | * @bit: the bit of the word being waited on | |
137 | * @action: the function used to sleep, which may take special actions | |
138 | * @mode: the task state to sleep in | |
139 | * | |
140 | * Use the standard hashed waitqueue table to wait for a bit | |
141 | * to be cleared, and allow the waiting action to be specified. | |
142 | * This is like wait_on_bit() but allows fine control of how the waiting | |
143 | * is done. | |
144 | * | |
145 | * Returned value will be zero if the bit was cleared, or non-zero | |
146 | * if the process received a signal and the mode permitted wakeup | |
147 | * on that signal. | |
148 | */ | |
149 | static inline int | |
150 | wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action, | |
151 | unsigned mode) | |
152 | { | |
153 | might_sleep(); | |
8238b457 | 154 | if (!test_bit_acquire(bit, word)) |
5dd43ce2 IM |
155 | return 0; |
156 | return out_of_line_wait_on_bit(word, bit, action, mode); | |
157 | } | |
158 | ||
159 | /** | |
160 | * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it | |
161 | * @word: the word being waited on, a kernel virtual address | |
162 | * @bit: the bit of the word being waited on | |
163 | * @mode: the task state to sleep in | |
164 | * | |
165 | * There is a standard hashed waitqueue table for generic use. This | |
166 | * is the part of the hashtable's accessor API that waits on a bit | |
167 | * when one intends to set it, for instance, trying to lock bitflags. | |
168 | * For instance, if one were to have waiters trying to set bitflag | |
169 | * and waiting for it to clear before setting it, one would call | |
170 | * wait_on_bit() in threads waiting to be able to set the bit. | |
171 | * One uses wait_on_bit_lock() where one is waiting for the bit to | |
172 | * clear with the intention of setting it, and when done, clearing it. | |
173 | * | |
174 | * Returns zero if the bit was (eventually) found to be clear and was | |
175 | * set. Returns non-zero if a signal was delivered to the process and | |
176 | * the @mode allows that signal to wake the process. | |
177 | */ | |
178 | static inline int | |
179 | wait_on_bit_lock(unsigned long *word, int bit, unsigned mode) | |
180 | { | |
181 | might_sleep(); | |
182 | if (!test_and_set_bit(bit, word)) | |
183 | return 0; | |
184 | return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode); | |
185 | } | |
186 | ||
187 | /** | |
188 | * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it | |
189 | * @word: the word being waited on, a kernel virtual address | |
190 | * @bit: the bit of the word being waited on | |
191 | * @mode: the task state to sleep in | |
192 | * | |
193 | * Use the standard hashed waitqueue table to wait for a bit | |
194 | * to be cleared and then to atomically set it. This is similar | |
195 | * to wait_on_bit(), but calls io_schedule() instead of schedule() | |
196 | * for the actual waiting. | |
197 | * | |
198 | * Returns zero if the bit was (eventually) found to be clear and was | |
199 | * set. Returns non-zero if a signal was delivered to the process and | |
200 | * the @mode allows that signal to wake the process. | |
201 | */ | |
202 | static inline int | |
203 | wait_on_bit_lock_io(unsigned long *word, int bit, unsigned mode) | |
204 | { | |
205 | might_sleep(); | |
206 | if (!test_and_set_bit(bit, word)) | |
207 | return 0; | |
208 | return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode); | |
209 | } | |
210 | ||
211 | /** | |
212 | * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it | |
213 | * @word: the word being waited on, a kernel virtual address | |
214 | * @bit: the bit of the word being waited on | |
215 | * @action: the function used to sleep, which may take special actions | |
216 | * @mode: the task state to sleep in | |
217 | * | |
218 | * Use the standard hashed waitqueue table to wait for a bit | |
219 | * to be cleared and then to set it, and allow the waiting action | |
220 | * to be specified. | |
221 | * This is like wait_on_bit() but allows fine control of how the waiting | |
222 | * is done. | |
223 | * | |
224 | * Returns zero if the bit was (eventually) found to be clear and was | |
225 | * set. Returns non-zero if a signal was delivered to the process and | |
226 | * the @mode allows that signal to wake the process. | |
227 | */ | |
228 | static inline int | |
229 | wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action, | |
230 | unsigned mode) | |
231 | { | |
232 | might_sleep(); | |
233 | if (!test_and_set_bit(bit, word)) | |
234 | return 0; | |
235 | return out_of_line_wait_on_bit_lock(word, bit, action, mode); | |
236 | } | |
237 | ||
6b2bb726 PZ |
238 | extern void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags); |
239 | extern void wake_up_var(void *var); | |
240 | extern wait_queue_head_t *__var_waitqueue(void *p); | |
241 | ||
242 | #define ___wait_var_event(var, condition, state, exclusive, ret, cmd) \ | |
243 | ({ \ | |
244 | __label__ __out; \ | |
245 | struct wait_queue_head *__wq_head = __var_waitqueue(var); \ | |
246 | struct wait_bit_queue_entry __wbq_entry; \ | |
247 | long __ret = ret; /* explicit shadow */ \ | |
248 | \ | |
249 | init_wait_var_entry(&__wbq_entry, var, \ | |
250 | exclusive ? WQ_FLAG_EXCLUSIVE : 0); \ | |
251 | for (;;) { \ | |
252 | long __int = prepare_to_wait_event(__wq_head, \ | |
253 | &__wbq_entry.wq_entry, \ | |
254 | state); \ | |
255 | if (condition) \ | |
256 | break; \ | |
257 | \ | |
258 | if (___wait_is_interruptible(state) && __int) { \ | |
259 | __ret = __int; \ | |
260 | goto __out; \ | |
261 | } \ | |
262 | \ | |
263 | cmd; \ | |
264 | } \ | |
265 | finish_wait(__wq_head, &__wbq_entry.wq_entry); \ | |
266 | __out: __ret; \ | |
267 | }) | |
268 | ||
269 | #define __wait_var_event(var, condition) \ | |
270 | ___wait_var_event(var, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ | |
271 | schedule()) | |
272 | ||
273 | #define wait_var_event(var, condition) \ | |
274 | do { \ | |
275 | might_sleep(); \ | |
276 | if (condition) \ | |
277 | break; \ | |
278 | __wait_var_event(var, condition); \ | |
279 | } while (0) | |
280 | ||
281 | #define __wait_var_event_killable(var, condition) \ | |
282 | ___wait_var_event(var, condition, TASK_KILLABLE, 0, 0, \ | |
283 | schedule()) | |
284 | ||
285 | #define wait_var_event_killable(var, condition) \ | |
286 | ({ \ | |
287 | int __ret = 0; \ | |
288 | might_sleep(); \ | |
289 | if (!(condition)) \ | |
290 | __ret = __wait_var_event_killable(var, condition); \ | |
291 | __ret; \ | |
292 | }) | |
293 | ||
294 | #define __wait_var_event_timeout(var, condition, timeout) \ | |
295 | ___wait_var_event(var, ___wait_cond_timeout(condition), \ | |
296 | TASK_UNINTERRUPTIBLE, 0, timeout, \ | |
297 | __ret = schedule_timeout(__ret)) | |
298 | ||
299 | #define wait_var_event_timeout(var, condition, timeout) \ | |
300 | ({ \ | |
301 | long __ret = timeout; \ | |
302 | might_sleep(); \ | |
303 | if (!___wait_cond_timeout(condition)) \ | |
304 | __ret = __wait_var_event_timeout(var, condition, timeout); \ | |
305 | __ret; \ | |
306 | }) | |
307 | ||
a49294ea DH |
308 | #define __wait_var_event_interruptible(var, condition) \ |
309 | ___wait_var_event(var, condition, TASK_INTERRUPTIBLE, 0, 0, \ | |
310 | schedule()) | |
311 | ||
312 | #define wait_var_event_interruptible(var, condition) \ | |
313 | ({ \ | |
314 | int __ret = 0; \ | |
315 | might_sleep(); \ | |
316 | if (!(condition)) \ | |
317 | __ret = __wait_var_event_interruptible(var, condition); \ | |
318 | __ret; \ | |
319 | }) | |
320 | ||
8236b0ae TH |
321 | /** |
322 | * clear_and_wake_up_bit - clear a bit and wake up anyone waiting on that bit | |
323 | * | |
324 | * @bit: the bit of the word being waited on | |
325 | * @word: the word being waited on, a kernel virtual address | |
326 | * | |
327 | * You can use this helper if bitflags are manipulated atomically rather than | |
328 | * non-atomically under a lock. | |
329 | */ | |
330 | static inline void clear_and_wake_up_bit(int bit, void *word) | |
331 | { | |
332 | clear_bit_unlock(bit, word); | |
333 | /* See wake_up_bit() for which memory barrier you need to use. */ | |
334 | smp_mb__after_atomic(); | |
335 | wake_up_bit(word, bit); | |
336 | } | |
337 | ||
5dd43ce2 | 338 | #endif /* _LINUX_WAIT_BIT_H */ |