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Commit | Line | Data |
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e1ad7468 DL |
1 | /* |
2 | * fs/eventfd.c | |
3 | * | |
4 | * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> | |
5 | * | |
6 | */ | |
7 | ||
8 | #include <linux/file.h> | |
9 | #include <linux/poll.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/fs.h> | |
174cd4b1 | 12 | #include <linux/sched/signal.h> |
e1ad7468 | 13 | #include <linux/kernel.h> |
5a0e3ad6 | 14 | #include <linux/slab.h> |
e1ad7468 DL |
15 | #include <linux/list.h> |
16 | #include <linux/spinlock.h> | |
17 | #include <linux/anon_inodes.h> | |
7747cdb2 | 18 | #include <linux/syscalls.h> |
630d9c47 | 19 | #include <linux/export.h> |
13389010 DL |
20 | #include <linux/kref.h> |
21 | #include <linux/eventfd.h> | |
cbac5542 CG |
22 | #include <linux/proc_fs.h> |
23 | #include <linux/seq_file.h> | |
e1ad7468 | 24 | |
fde5fd9c JA |
25 | DEFINE_PER_CPU(int, eventfd_wake_count); |
26 | ||
e1ad7468 | 27 | struct eventfd_ctx { |
13389010 | 28 | struct kref kref; |
e1ad7468 DL |
29 | wait_queue_head_t wqh; |
30 | /* | |
31 | * Every time that a write(2) is performed on an eventfd, the | |
32 | * value of the __u64 being written is added to "count" and a | |
33 | * wakeup is performed on "wqh". A read(2) will return the "count" | |
34 | * value to userspace, and will reset "count" to zero. The kernel | |
13389010 | 35 | * side eventfd_signal() also, adds to the "count" counter and |
e1ad7468 DL |
36 | * issue a wakeup. |
37 | */ | |
38 | __u64 count; | |
bcd0b235 | 39 | unsigned int flags; |
e1ad7468 DL |
40 | }; |
41 | ||
13389010 DL |
42 | /** |
43 | * eventfd_signal - Adds @n to the eventfd counter. | |
44 | * @ctx: [in] Pointer to the eventfd context. | |
45 | * @n: [in] Value of the counter to be added to the eventfd internal counter. | |
46 | * The value cannot be negative. | |
47 | * | |
48 | * This function is supposed to be called by the kernel in paths that do not | |
49 | * allow sleeping. In this function we allow the counter to reach the ULLONG_MAX | |
20d5a865 | 50 | * value, and we signal this as overflow condition by returning a POLLERR |
13389010 DL |
51 | * to poll(2). |
52 | * | |
20d5a865 | 53 | * Returns the amount by which the counter was incremented. This will be less |
ee62c6b2 | 54 | * than @n if the counter has overflowed. |
e1ad7468 | 55 | */ |
ee62c6b2 | 56 | __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) |
e1ad7468 | 57 | { |
e1ad7468 DL |
58 | unsigned long flags; |
59 | ||
fde5fd9c JA |
60 | /* |
61 | * Deadlock or stack overflow issues can happen if we recurse here | |
62 | * through waitqueue wakeup handlers. If the caller users potentially | |
63 | * nested waitqueues with custom wakeup handlers, then it should | |
64 | * check eventfd_signal_count() before calling this function. If | |
65 | * it returns true, the eventfd_signal() call should be deferred to a | |
66 | * safe context. | |
67 | */ | |
68 | if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count))) | |
69 | return 0; | |
70 | ||
d48eb233 | 71 | spin_lock_irqsave(&ctx->wqh.lock, flags); |
fde5fd9c | 72 | this_cpu_inc(eventfd_wake_count); |
e1ad7468 | 73 | if (ULLONG_MAX - ctx->count < n) |
ee62c6b2 | 74 | n = ULLONG_MAX - ctx->count; |
e1ad7468 DL |
75 | ctx->count += n; |
76 | if (waitqueue_active(&ctx->wqh)) | |
39510888 | 77 | wake_up_locked_poll(&ctx->wqh, POLLIN); |
fde5fd9c | 78 | this_cpu_dec(eventfd_wake_count); |
d48eb233 | 79 | spin_unlock_irqrestore(&ctx->wqh.lock, flags); |
e1ad7468 DL |
80 | |
81 | return n; | |
82 | } | |
5718607b | 83 | EXPORT_SYMBOL_GPL(eventfd_signal); |
e1ad7468 | 84 | |
562787a5 DL |
85 | static void eventfd_free_ctx(struct eventfd_ctx *ctx) |
86 | { | |
87 | kfree(ctx); | |
88 | } | |
89 | ||
13389010 DL |
90 | static void eventfd_free(struct kref *kref) |
91 | { | |
92 | struct eventfd_ctx *ctx = container_of(kref, struct eventfd_ctx, kref); | |
93 | ||
562787a5 | 94 | eventfd_free_ctx(ctx); |
13389010 DL |
95 | } |
96 | ||
97 | /** | |
98 | * eventfd_ctx_get - Acquires a reference to the internal eventfd context. | |
99 | * @ctx: [in] Pointer to the eventfd context. | |
100 | * | |
101 | * Returns: In case of success, returns a pointer to the eventfd context. | |
102 | */ | |
103 | struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx) | |
104 | { | |
105 | kref_get(&ctx->kref); | |
106 | return ctx; | |
107 | } | |
108 | EXPORT_SYMBOL_GPL(eventfd_ctx_get); | |
109 | ||
110 | /** | |
111 | * eventfd_ctx_put - Releases a reference to the internal eventfd context. | |
112 | * @ctx: [in] Pointer to eventfd context. | |
113 | * | |
114 | * The eventfd context reference must have been previously acquired either | |
36182185 | 115 | * with eventfd_ctx_get() or eventfd_ctx_fdget(). |
13389010 DL |
116 | */ |
117 | void eventfd_ctx_put(struct eventfd_ctx *ctx) | |
118 | { | |
119 | kref_put(&ctx->kref, eventfd_free); | |
120 | } | |
121 | EXPORT_SYMBOL_GPL(eventfd_ctx_put); | |
122 | ||
e1ad7468 DL |
123 | static int eventfd_release(struct inode *inode, struct file *file) |
124 | { | |
13389010 DL |
125 | struct eventfd_ctx *ctx = file->private_data; |
126 | ||
127 | wake_up_poll(&ctx->wqh, POLLHUP); | |
128 | eventfd_ctx_put(ctx); | |
e1ad7468 DL |
129 | return 0; |
130 | } | |
131 | ||
132 | static unsigned int eventfd_poll(struct file *file, poll_table *wait) | |
133 | { | |
134 | struct eventfd_ctx *ctx = file->private_data; | |
135 | unsigned int events = 0; | |
e22553e2 | 136 | u64 count; |
e1ad7468 DL |
137 | |
138 | poll_wait(file, &ctx->wqh, wait); | |
a484c3dd PB |
139 | |
140 | /* | |
141 | * All writes to ctx->count occur within ctx->wqh.lock. This read | |
142 | * can be done outside ctx->wqh.lock because we know that poll_wait | |
143 | * takes that lock (through add_wait_queue) if our caller will sleep. | |
144 | * | |
145 | * The read _can_ therefore seep into add_wait_queue's critical | |
146 | * section, but cannot move above it! add_wait_queue's spin_lock acts | |
147 | * as an acquire barrier and ensures that the read be ordered properly | |
148 | * against the writes. The following CAN happen and is safe: | |
149 | * | |
150 | * poll write | |
151 | * ----------------- ------------ | |
152 | * lock ctx->wqh.lock (in poll_wait) | |
153 | * count = ctx->count | |
154 | * __add_wait_queue | |
155 | * unlock ctx->wqh.lock | |
156 | * lock ctx->qwh.lock | |
157 | * ctx->count += n | |
158 | * if (waitqueue_active) | |
159 | * wake_up_locked_poll | |
160 | * unlock ctx->qwh.lock | |
161 | * eventfd_poll returns 0 | |
162 | * | |
163 | * but the following, which would miss a wakeup, cannot happen: | |
164 | * | |
165 | * poll write | |
166 | * ----------------- ------------ | |
167 | * count = ctx->count (INVALID!) | |
168 | * lock ctx->qwh.lock | |
169 | * ctx->count += n | |
170 | * **waitqueue_active is false** | |
171 | * **no wake_up_locked_poll!** | |
172 | * unlock ctx->qwh.lock | |
173 | * lock ctx->wqh.lock (in poll_wait) | |
174 | * __add_wait_queue | |
175 | * unlock ctx->wqh.lock | |
176 | * eventfd_poll returns 0 | |
177 | */ | |
178 | count = READ_ONCE(ctx->count); | |
e1ad7468 | 179 | |
e22553e2 | 180 | if (count > 0) |
e1ad7468 | 181 | events |= POLLIN; |
e22553e2 | 182 | if (count == ULLONG_MAX) |
e1ad7468 | 183 | events |= POLLERR; |
e22553e2 | 184 | if (ULLONG_MAX - 1 > count) |
e1ad7468 | 185 | events |= POLLOUT; |
e1ad7468 DL |
186 | |
187 | return events; | |
188 | } | |
189 | ||
cb289d62 DL |
190 | static void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) |
191 | { | |
192 | *cnt = (ctx->flags & EFD_SEMAPHORE) ? 1 : ctx->count; | |
193 | ctx->count -= *cnt; | |
194 | } | |
195 | ||
196 | /** | |
197 | * eventfd_ctx_remove_wait_queue - Read the current counter and removes wait queue. | |
198 | * @ctx: [in] Pointer to eventfd context. | |
199 | * @wait: [in] Wait queue to be removed. | |
36182185 | 200 | * @cnt: [out] Pointer to the 64-bit counter value. |
cb289d62 | 201 | * |
36182185 | 202 | * Returns %0 if successful, or the following error codes: |
cb289d62 DL |
203 | * |
204 | * -EAGAIN : The operation would have blocked. | |
205 | * | |
206 | * This is used to atomically remove a wait queue entry from the eventfd wait | |
207 | * queue head, and read/reset the counter value. | |
208 | */ | |
ac6424b9 | 209 | int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, |
cb289d62 DL |
210 | __u64 *cnt) |
211 | { | |
212 | unsigned long flags; | |
213 | ||
214 | spin_lock_irqsave(&ctx->wqh.lock, flags); | |
215 | eventfd_ctx_do_read(ctx, cnt); | |
216 | __remove_wait_queue(&ctx->wqh, wait); | |
217 | if (*cnt != 0 && waitqueue_active(&ctx->wqh)) | |
218 | wake_up_locked_poll(&ctx->wqh, POLLOUT); | |
219 | spin_unlock_irqrestore(&ctx->wqh.lock, flags); | |
220 | ||
221 | return *cnt != 0 ? 0 : -EAGAIN; | |
222 | } | |
223 | EXPORT_SYMBOL_GPL(eventfd_ctx_remove_wait_queue); | |
224 | ||
225 | /** | |
226 | * eventfd_ctx_read - Reads the eventfd counter or wait if it is zero. | |
227 | * @ctx: [in] Pointer to eventfd context. | |
228 | * @no_wait: [in] Different from zero if the operation should not block. | |
36182185 | 229 | * @cnt: [out] Pointer to the 64-bit counter value. |
cb289d62 | 230 | * |
36182185 | 231 | * Returns %0 if successful, or the following error codes: |
cb289d62 | 232 | * |
f16df9f7 MCC |
233 | * - -EAGAIN : The operation would have blocked but @no_wait was non-zero. |
234 | * - -ERESTARTSYS : A signal interrupted the wait operation. | |
cb289d62 DL |
235 | * |
236 | * If @no_wait is zero, the function might sleep until the eventfd internal | |
237 | * counter becomes greater than zero. | |
238 | */ | |
239 | ssize_t eventfd_ctx_read(struct eventfd_ctx *ctx, int no_wait, __u64 *cnt) | |
e1ad7468 | 240 | { |
e1ad7468 | 241 | ssize_t res; |
e1ad7468 DL |
242 | DECLARE_WAITQUEUE(wait, current); |
243 | ||
d48eb233 | 244 | spin_lock_irq(&ctx->wqh.lock); |
cb289d62 | 245 | *cnt = 0; |
e1ad7468 | 246 | res = -EAGAIN; |
bcd0b235 | 247 | if (ctx->count > 0) |
cb289d62 DL |
248 | res = 0; |
249 | else if (!no_wait) { | |
e1ad7468 | 250 | __add_wait_queue(&ctx->wqh, &wait); |
cb289d62 | 251 | for (;;) { |
e1ad7468 DL |
252 | set_current_state(TASK_INTERRUPTIBLE); |
253 | if (ctx->count > 0) { | |
cb289d62 | 254 | res = 0; |
e1ad7468 DL |
255 | break; |
256 | } | |
257 | if (signal_pending(current)) { | |
258 | res = -ERESTARTSYS; | |
259 | break; | |
260 | } | |
d48eb233 | 261 | spin_unlock_irq(&ctx->wqh.lock); |
e1ad7468 | 262 | schedule(); |
d48eb233 | 263 | spin_lock_irq(&ctx->wqh.lock); |
e1ad7468 DL |
264 | } |
265 | __remove_wait_queue(&ctx->wqh, &wait); | |
266 | __set_current_state(TASK_RUNNING); | |
267 | } | |
cb289d62 DL |
268 | if (likely(res == 0)) { |
269 | eventfd_ctx_do_read(ctx, cnt); | |
e1ad7468 | 270 | if (waitqueue_active(&ctx->wqh)) |
39510888 | 271 | wake_up_locked_poll(&ctx->wqh, POLLOUT); |
e1ad7468 | 272 | } |
d48eb233 | 273 | spin_unlock_irq(&ctx->wqh.lock); |
e1ad7468 DL |
274 | |
275 | return res; | |
276 | } | |
cb289d62 DL |
277 | EXPORT_SYMBOL_GPL(eventfd_ctx_read); |
278 | ||
279 | static ssize_t eventfd_read(struct file *file, char __user *buf, size_t count, | |
280 | loff_t *ppos) | |
281 | { | |
282 | struct eventfd_ctx *ctx = file->private_data; | |
283 | ssize_t res; | |
284 | __u64 cnt; | |
285 | ||
286 | if (count < sizeof(cnt)) | |
287 | return -EINVAL; | |
288 | res = eventfd_ctx_read(ctx, file->f_flags & O_NONBLOCK, &cnt); | |
289 | if (res < 0) | |
290 | return res; | |
291 | ||
292 | return put_user(cnt, (__u64 __user *) buf) ? -EFAULT : sizeof(cnt); | |
293 | } | |
e1ad7468 DL |
294 | |
295 | static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t count, | |
296 | loff_t *ppos) | |
297 | { | |
298 | struct eventfd_ctx *ctx = file->private_data; | |
299 | ssize_t res; | |
300 | __u64 ucnt; | |
301 | DECLARE_WAITQUEUE(wait, current); | |
302 | ||
303 | if (count < sizeof(ucnt)) | |
304 | return -EINVAL; | |
305 | if (copy_from_user(&ucnt, buf, sizeof(ucnt))) | |
306 | return -EFAULT; | |
307 | if (ucnt == ULLONG_MAX) | |
308 | return -EINVAL; | |
d48eb233 | 309 | spin_lock_irq(&ctx->wqh.lock); |
e1ad7468 DL |
310 | res = -EAGAIN; |
311 | if (ULLONG_MAX - ctx->count > ucnt) | |
312 | res = sizeof(ucnt); | |
313 | else if (!(file->f_flags & O_NONBLOCK)) { | |
314 | __add_wait_queue(&ctx->wqh, &wait); | |
315 | for (res = 0;;) { | |
316 | set_current_state(TASK_INTERRUPTIBLE); | |
317 | if (ULLONG_MAX - ctx->count > ucnt) { | |
318 | res = sizeof(ucnt); | |
319 | break; | |
320 | } | |
321 | if (signal_pending(current)) { | |
322 | res = -ERESTARTSYS; | |
323 | break; | |
324 | } | |
d48eb233 | 325 | spin_unlock_irq(&ctx->wqh.lock); |
e1ad7468 | 326 | schedule(); |
d48eb233 | 327 | spin_lock_irq(&ctx->wqh.lock); |
e1ad7468 DL |
328 | } |
329 | __remove_wait_queue(&ctx->wqh, &wait); | |
330 | __set_current_state(TASK_RUNNING); | |
331 | } | |
bcd0b235 | 332 | if (likely(res > 0)) { |
e1ad7468 DL |
333 | ctx->count += ucnt; |
334 | if (waitqueue_active(&ctx->wqh)) | |
39510888 | 335 | wake_up_locked_poll(&ctx->wqh, POLLIN); |
e1ad7468 | 336 | } |
d48eb233 | 337 | spin_unlock_irq(&ctx->wqh.lock); |
e1ad7468 DL |
338 | |
339 | return res; | |
340 | } | |
341 | ||
cbac5542 | 342 | #ifdef CONFIG_PROC_FS |
a3816ab0 | 343 | static void eventfd_show_fdinfo(struct seq_file *m, struct file *f) |
cbac5542 CG |
344 | { |
345 | struct eventfd_ctx *ctx = f->private_data; | |
cbac5542 CG |
346 | |
347 | spin_lock_irq(&ctx->wqh.lock); | |
a3816ab0 JP |
348 | seq_printf(m, "eventfd-count: %16llx\n", |
349 | (unsigned long long)ctx->count); | |
cbac5542 | 350 | spin_unlock_irq(&ctx->wqh.lock); |
cbac5542 CG |
351 | } |
352 | #endif | |
353 | ||
e1ad7468 | 354 | static const struct file_operations eventfd_fops = { |
cbac5542 CG |
355 | #ifdef CONFIG_PROC_FS |
356 | .show_fdinfo = eventfd_show_fdinfo, | |
357 | #endif | |
e1ad7468 DL |
358 | .release = eventfd_release, |
359 | .poll = eventfd_poll, | |
360 | .read = eventfd_read, | |
361 | .write = eventfd_write, | |
6038f373 | 362 | .llseek = noop_llseek, |
e1ad7468 DL |
363 | }; |
364 | ||
13389010 DL |
365 | /** |
366 | * eventfd_fget - Acquire a reference of an eventfd file descriptor. | |
367 | * @fd: [in] Eventfd file descriptor. | |
368 | * | |
369 | * Returns a pointer to the eventfd file structure in case of success, or the | |
370 | * following error pointer: | |
371 | * | |
372 | * -EBADF : Invalid @fd file descriptor. | |
373 | * -EINVAL : The @fd file descriptor is not an eventfd file. | |
374 | */ | |
e1ad7468 DL |
375 | struct file *eventfd_fget(int fd) |
376 | { | |
377 | struct file *file; | |
378 | ||
379 | file = fget(fd); | |
380 | if (!file) | |
381 | return ERR_PTR(-EBADF); | |
382 | if (file->f_op != &eventfd_fops) { | |
383 | fput(file); | |
384 | return ERR_PTR(-EINVAL); | |
385 | } | |
386 | ||
387 | return file; | |
388 | } | |
5718607b | 389 | EXPORT_SYMBOL_GPL(eventfd_fget); |
e1ad7468 | 390 | |
13389010 DL |
391 | /** |
392 | * eventfd_ctx_fdget - Acquires a reference to the internal eventfd context. | |
393 | * @fd: [in] Eventfd file descriptor. | |
394 | * | |
395 | * Returns a pointer to the internal eventfd context, otherwise the error | |
396 | * pointers returned by the following functions: | |
397 | * | |
398 | * eventfd_fget | |
399 | */ | |
400 | struct eventfd_ctx *eventfd_ctx_fdget(int fd) | |
401 | { | |
13389010 | 402 | struct eventfd_ctx *ctx; |
36a74117 AV |
403 | struct fd f = fdget(fd); |
404 | if (!f.file) | |
405 | return ERR_PTR(-EBADF); | |
406 | ctx = eventfd_ctx_fileget(f.file); | |
407 | fdput(f); | |
13389010 DL |
408 | return ctx; |
409 | } | |
410 | EXPORT_SYMBOL_GPL(eventfd_ctx_fdget); | |
411 | ||
412 | /** | |
413 | * eventfd_ctx_fileget - Acquires a reference to the internal eventfd context. | |
414 | * @file: [in] Eventfd file pointer. | |
415 | * | |
416 | * Returns a pointer to the internal eventfd context, otherwise the error | |
417 | * pointer: | |
418 | * | |
419 | * -EINVAL : The @fd file descriptor is not an eventfd file. | |
420 | */ | |
421 | struct eventfd_ctx *eventfd_ctx_fileget(struct file *file) | |
422 | { | |
423 | if (file->f_op != &eventfd_fops) | |
424 | return ERR_PTR(-EINVAL); | |
425 | ||
426 | return eventfd_ctx_get(file->private_data); | |
427 | } | |
428 | EXPORT_SYMBOL_GPL(eventfd_ctx_fileget); | |
429 | ||
562787a5 DL |
430 | /** |
431 | * eventfd_file_create - Creates an eventfd file pointer. | |
432 | * @count: Initial eventfd counter value. | |
433 | * @flags: Flags for the eventfd file. | |
434 | * | |
435 | * This function creates an eventfd file pointer, w/out installing it into | |
436 | * the fd table. This is useful when the eventfd file is used during the | |
437 | * initialization of data structures that require extra setup after the eventfd | |
438 | * creation. So the eventfd creation is split into the file pointer creation | |
439 | * phase, and the file descriptor installation phase. | |
440 | * In this way races with userspace closing the newly installed file descriptor | |
441 | * can be avoided. | |
442 | * Returns an eventfd file pointer, or a proper error pointer. | |
443 | */ | |
444 | struct file *eventfd_file_create(unsigned int count, int flags) | |
e1ad7468 | 445 | { |
562787a5 | 446 | struct file *file; |
e1ad7468 | 447 | struct eventfd_ctx *ctx; |
e1ad7468 | 448 | |
e38b36f3 UD |
449 | /* Check the EFD_* constants for consistency. */ |
450 | BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC); | |
451 | BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK); | |
452 | ||
bcd0b235 | 453 | if (flags & ~EFD_FLAGS_SET) |
562787a5 | 454 | return ERR_PTR(-EINVAL); |
b087498e | 455 | |
e1ad7468 DL |
456 | ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); |
457 | if (!ctx) | |
562787a5 | 458 | return ERR_PTR(-ENOMEM); |
e1ad7468 | 459 | |
13389010 | 460 | kref_init(&ctx->kref); |
e1ad7468 | 461 | init_waitqueue_head(&ctx->wqh); |
e1ad7468 | 462 | ctx->count = count; |
bcd0b235 | 463 | ctx->flags = flags; |
e1ad7468 | 464 | |
562787a5 | 465 | file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx, |
628ff7c1 | 466 | O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS)); |
562787a5 DL |
467 | if (IS_ERR(file)) |
468 | eventfd_free_ctx(ctx); | |
469 | ||
470 | return file; | |
471 | } | |
472 | ||
473 | SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags) | |
474 | { | |
475 | int fd, error; | |
476 | struct file *file; | |
477 | ||
478 | error = get_unused_fd_flags(flags & EFD_SHARED_FCNTL_FLAGS); | |
479 | if (error < 0) | |
480 | return error; | |
481 | fd = error; | |
482 | ||
483 | file = eventfd_file_create(count, flags); | |
484 | if (IS_ERR(file)) { | |
485 | error = PTR_ERR(file); | |
486 | goto err_put_unused_fd; | |
487 | } | |
488 | fd_install(fd, file); | |
489 | ||
2030a42c | 490 | return fd; |
562787a5 DL |
491 | |
492 | err_put_unused_fd: | |
493 | put_unused_fd(fd); | |
494 | ||
495 | return error; | |
e1ad7468 DL |
496 | } |
497 | ||
d4e82042 | 498 | SYSCALL_DEFINE1(eventfd, unsigned int, count) |
b087498e UD |
499 | { |
500 | return sys_eventfd2(count, 0); | |
501 | } | |
bcd0b235 | 502 |