Lines Matching full:pipe
3 * linux/fs/pipe.c
36 * New pipe buffers will be restricted to this size while the user is exceeding
37 * their pipe buffer quota. The general pipe use case needs at least two
39 * than two, then a write to a non-empty pipe may block even if the pipe is not
42 * pipe before reading tokens: https://lore.kernel.org/lkml/1628086770.5rn8p04n6j.none@localhost/.
44 * Users can reduce their pipe buffers with F_SETPIPE_SZ below this at their
45 * own risk, namely: pipe writes to non-full pipes may block until the pipe is
51 * The max size that a non-root user is allowed to grow the pipe. Can
52 * be set by root in /proc/sys/fs/pipe-max-size
89 void pipe_lock(struct pipe_inode_info *pipe) in pipe_lock() argument
91 if (pipe->files) in pipe_lock()
92 mutex_lock(&pipe->mutex); in pipe_lock()
96 void pipe_unlock(struct pipe_inode_info *pipe) in pipe_unlock() argument
98 if (pipe->files) in pipe_unlock()
99 mutex_unlock(&pipe->mutex); in pipe_unlock()
115 static void anon_pipe_buf_release(struct pipe_inode_info *pipe, in anon_pipe_buf_release() argument
125 if (page_count(page) == 1 && !pipe->tmp_page) in anon_pipe_buf_release()
126 pipe->tmp_page = page; in anon_pipe_buf_release()
131 static bool anon_pipe_buf_try_steal(struct pipe_inode_info *pipe, in anon_pipe_buf_try_steal() argument
145 * @pipe: the pipe that the buffer belongs to
155 bool generic_pipe_buf_try_steal(struct pipe_inode_info *pipe, in generic_pipe_buf_try_steal() argument
175 * @pipe: the pipe that the buffer belongs to
181 * pipe into another.
183 bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) in generic_pipe_buf_get() argument
191 * @pipe: the pipe that the buffer belongs to
197 void generic_pipe_buf_release(struct pipe_inode_info *pipe, in generic_pipe_buf_release() argument
210 /* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
211 static inline bool pipe_readable(const struct pipe_inode_info *pipe) in pipe_readable() argument
213 union pipe_index idx = { .head_tail = READ_ONCE(pipe->head_tail) }; in pipe_readable()
214 unsigned int writers = READ_ONCE(pipe->writers); in pipe_readable()
219 static inline unsigned int pipe_update_tail(struct pipe_inode_info *pipe, in pipe_update_tail() argument
223 pipe_buf_release(pipe, buf); in pipe_update_tail()
226 * If the pipe has a watch_queue, we need additional protection in pipe_update_tail()
230 if (pipe_has_watch_queue(pipe)) { in pipe_update_tail()
231 spin_lock_irq(&pipe->rd_wait.lock); in pipe_update_tail()
234 pipe->note_loss = true; in pipe_update_tail()
236 pipe->tail = ++tail; in pipe_update_tail()
237 spin_unlock_irq(&pipe->rd_wait.lock); in pipe_update_tail()
245 pipe->tail = ++tail; in pipe_update_tail()
254 struct pipe_inode_info *pipe = filp->private_data; in pipe_read() local
263 mutex_lock(&pipe->mutex); in pipe_read()
266 * We only wake up writers if the pipe was full when we started reading in pipe_read()
275 unsigned int head = smp_load_acquire(&pipe->head); in pipe_read()
276 unsigned int tail = pipe->tail; in pipe_read()
277 unsigned int mask = pipe->ring_size - 1; in pipe_read()
280 if (pipe->note_loss) { in pipe_read()
299 pipe->note_loss = false; in pipe_read()
304 struct pipe_buffer *buf = &pipe->bufs[tail & mask]; in pipe_read()
318 error = pipe_buf_confirm(pipe, buf); in pipe_read()
342 wake_writer |= pipe_full(head, tail, pipe->max_usage); in pipe_read()
343 tail = pipe_update_tail(pipe, buf, tail); in pipe_read()
352 if (!pipe->writers) in pipe_read()
361 mutex_unlock(&pipe->mutex); in pipe_read()
367 * pipe buffer, and might have made space in the buffers in pipe_read()
370 * You can't make zero-sized pipe buffers by doing an empty in pipe_read()
377 * _very_ unlikely case that the pipe was full, but we got in pipe_read()
381 wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); in pipe_read()
382 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); in pipe_read()
390 if (wait_event_interruptible_exclusive(pipe->rd_wait, pipe_readable(pipe)) < 0) in pipe_read()
395 mutex_lock(&pipe->mutex); in pipe_read()
397 if (pipe_is_empty(pipe)) in pipe_read()
399 mutex_unlock(&pipe->mutex); in pipe_read()
402 wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); in pipe_read()
404 wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); in pipe_read()
405 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); in pipe_read()
416 /* Done while waiting without holding the pipe lock - thus the READ_ONCE() */
417 static inline bool pipe_writable(const struct pipe_inode_info *pipe) in pipe_writable() argument
419 union pipe_index idx = { .head_tail = READ_ONCE(pipe->head_tail) }; in pipe_writable()
420 unsigned int max_usage = READ_ONCE(pipe->max_usage); in pipe_writable()
423 !READ_ONCE(pipe->readers); in pipe_writable()
430 struct pipe_inode_info *pipe = filp->private_data; in pipe_write() local
440 * the pipe. in pipe_write()
442 * pipe locked. in pipe_write()
443 * If we had to support locking a normal pipe and a notification pipe at in pipe_write()
447 if (pipe_has_watch_queue(pipe)) in pipe_write()
454 mutex_lock(&pipe->mutex); in pipe_write()
456 if (!pipe->readers) { in pipe_write()
470 head = pipe->head; in pipe_write()
471 was_empty = pipe_empty(head, pipe->tail); in pipe_write()
474 unsigned int mask = pipe->ring_size - 1; in pipe_write()
475 struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask]; in pipe_write()
480 ret = pipe_buf_confirm(pipe, buf); in pipe_write()
497 if (!pipe->readers) { in pipe_write()
504 head = pipe->head; in pipe_write()
505 if (!pipe_full(head, pipe->tail, pipe->max_usage)) { in pipe_write()
506 unsigned int mask = pipe->ring_size - 1; in pipe_write()
508 struct page *page = pipe->tmp_page; in pipe_write()
517 pipe->tmp_page = page; in pipe_write()
525 pipe->head = head + 1; in pipe_write()
528 buf = &pipe->bufs[head & mask]; in pipe_write()
537 pipe->tmp_page = NULL; in pipe_write()
552 if (!pipe_full(head, pipe->tail, pipe->max_usage)) in pipe_write()
569 * We're going to release the pipe lock and wait for more in pipe_write()
571 * after waiting we need to re-check whether the pipe in pipe_write()
574 mutex_unlock(&pipe->mutex); in pipe_write()
576 wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); in pipe_write()
577 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); in pipe_write()
578 wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe)); in pipe_write()
579 mutex_lock(&pipe->mutex); in pipe_write()
580 was_empty = pipe_is_empty(pipe); in pipe_write()
584 if (pipe_is_full(pipe)) in pipe_write()
586 mutex_unlock(&pipe->mutex); in pipe_write()
597 * Epoll nonsensically wants a wakeup whether the pipe in pipe_write()
600 if (was_empty || pipe->poll_usage) in pipe_write()
601 wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); in pipe_write()
602 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); in pipe_write()
604 wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); in pipe_write()
616 struct pipe_inode_info *pipe = filp->private_data; in pipe_ioctl() local
621 mutex_lock(&pipe->mutex); in pipe_ioctl()
623 head = pipe->head; in pipe_ioctl()
624 tail = pipe->tail; in pipe_ioctl()
627 count += pipe_buf(pipe, tail)->len; in pipe_ioctl()
630 mutex_unlock(&pipe->mutex); in pipe_ioctl()
637 mutex_lock(&pipe->mutex); in pipe_ioctl()
638 ret = watch_queue_set_size(pipe, arg); in pipe_ioctl()
639 mutex_unlock(&pipe->mutex); in pipe_ioctl()
645 pipe, (struct watch_notification_filter __user *)arg); in pipe_ioctl()
658 struct pipe_inode_info *pipe = filp->private_data; in pipe_poll() local
662 WRITE_ONCE(pipe->poll_usage, true); in pipe_poll()
665 * Reading pipe state only -- no need for acquiring the semaphore. in pipe_poll()
671 poll_wait(filp, &pipe->rd_wait, wait); in pipe_poll()
673 poll_wait(filp, &pipe->wr_wait, wait); in pipe_poll()
680 idx.head_tail = READ_ONCE(pipe->head_tail); in pipe_poll()
686 if (!pipe->writers && filp->f_pipe != pipe->w_counter) in pipe_poll()
691 if (!pipe_full(idx.head, idx.tail, pipe->max_usage)) in pipe_poll()
697 if (!pipe->readers) in pipe_poll()
704 static void put_pipe_info(struct inode *inode, struct pipe_inode_info *pipe) in put_pipe_info() argument
709 if (!--pipe->files) { in put_pipe_info()
716 free_pipe_info(pipe); in put_pipe_info()
722 struct pipe_inode_info *pipe = file->private_data; in pipe_release() local
724 mutex_lock(&pipe->mutex); in pipe_release()
726 pipe->readers--; in pipe_release()
728 pipe->writers--; in pipe_release()
731 if (!pipe->readers != !pipe->writers) { in pipe_release()
732 wake_up_interruptible_all(&pipe->rd_wait); in pipe_release()
733 wake_up_interruptible_all(&pipe->wr_wait); in pipe_release()
734 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); in pipe_release()
735 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); in pipe_release()
737 mutex_unlock(&pipe->mutex); in pipe_release()
739 put_pipe_info(inode, pipe); in pipe_release()
746 struct pipe_inode_info *pipe = filp->private_data; in pipe_fasync() local
749 mutex_lock(&pipe->mutex); in pipe_fasync()
751 retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); in pipe_fasync()
753 retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); in pipe_fasync()
756 fasync_helper(-1, filp, 0, &pipe->fasync_readers); in pipe_fasync()
758 mutex_unlock(&pipe->mutex); in pipe_fasync()
789 struct pipe_inode_info *pipe; in alloc_pipe_info() local
795 pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL_ACCOUNT); in alloc_pipe_info()
796 if (pipe == NULL) in alloc_pipe_info()
812 pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer), in alloc_pipe_info()
815 if (pipe->bufs) { in alloc_pipe_info()
816 init_waitqueue_head(&pipe->rd_wait); in alloc_pipe_info()
817 init_waitqueue_head(&pipe->wr_wait); in alloc_pipe_info()
818 pipe->r_counter = pipe->w_counter = 1; in alloc_pipe_info()
819 pipe->max_usage = pipe_bufs; in alloc_pipe_info()
820 pipe->ring_size = pipe_bufs; in alloc_pipe_info()
821 pipe->nr_accounted = pipe_bufs; in alloc_pipe_info()
822 pipe->user = user; in alloc_pipe_info()
823 mutex_init(&pipe->mutex); in alloc_pipe_info()
824 lock_set_cmp_fn(&pipe->mutex, pipe_lock_cmp_fn, NULL); in alloc_pipe_info()
825 return pipe; in alloc_pipe_info()
830 kfree(pipe); in alloc_pipe_info()
836 void free_pipe_info(struct pipe_inode_info *pipe) in free_pipe_info() argument
841 if (pipe->watch_queue) in free_pipe_info()
842 watch_queue_clear(pipe->watch_queue); in free_pipe_info()
845 (void) account_pipe_buffers(pipe->user, pipe->nr_accounted, 0); in free_pipe_info()
846 free_uid(pipe->user); in free_pipe_info()
847 for (i = 0; i < pipe->ring_size; i++) { in free_pipe_info()
848 struct pipe_buffer *buf = pipe->bufs + i; in free_pipe_info()
850 pipe_buf_release(pipe, buf); in free_pipe_info()
853 if (pipe->watch_queue) in free_pipe_info()
854 put_watch_queue(pipe->watch_queue); in free_pipe_info()
856 if (pipe->tmp_page) in free_pipe_info()
857 __free_page(pipe->tmp_page); in free_pipe_info()
858 kfree(pipe->bufs); in free_pipe_info()
859 kfree(pipe); in free_pipe_info()
869 return dynamic_dname(buffer, buflen, "pipe:[%lu]", in pipefs_dname()
880 struct pipe_inode_info *pipe; in get_pipe_inode() local
887 pipe = alloc_pipe_info(); in get_pipe_inode()
888 if (!pipe) in get_pipe_inode()
891 inode->i_pipe = pipe; in get_pipe_inode()
892 pipe->files = 2; in get_pipe_inode()
893 pipe->readers = pipe->writers = 1; in get_pipe_inode()
993 /* pipe groks IOCB_NOWAIT */ in __do_pipe_flags()
1019 * a pipe. It's not the way Unix traditionally does this, though.
1048 SYSCALL_DEFINE1(pipe, int __user *, fildes) in SYSCALL_DEFINE1() argument
1054 * This is the stupid "wait for pipe to be readable or writable"
1062 void pipe_wait_readable(struct pipe_inode_info *pipe) in pipe_wait_readable() argument
1064 pipe_unlock(pipe); in pipe_wait_readable()
1065 wait_event_interruptible(pipe->rd_wait, pipe_readable(pipe)); in pipe_wait_readable()
1066 pipe_lock(pipe); in pipe_wait_readable()
1069 void pipe_wait_writable(struct pipe_inode_info *pipe) in pipe_wait_writable() argument
1071 pipe_unlock(pipe); in pipe_wait_writable()
1072 wait_event_interruptible(pipe->wr_wait, pipe_writable(pipe)); in pipe_wait_writable()
1073 pipe_lock(pipe); in pipe_wait_writable()
1078 * holding the pipe lock, so "*cnt" is stable and we know a wakeup cannot
1083 * because of the pipe lock, we can check the condition before being on
1086 * We use the 'rd_wait' waitqueue for pipe partner waiting.
1088 static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt) in wait_for_partner() argument
1094 prepare_to_wait(&pipe->rd_wait, &rdwait, TASK_INTERRUPTIBLE); in wait_for_partner()
1095 pipe_unlock(pipe); in wait_for_partner()
1097 finish_wait(&pipe->rd_wait, &rdwait); in wait_for_partner()
1098 pipe_lock(pipe); in wait_for_partner()
1105 static void wake_up_partner(struct pipe_inode_info *pipe) in wake_up_partner() argument
1107 wake_up_interruptible_all(&pipe->rd_wait); in wake_up_partner()
1112 struct pipe_inode_info *pipe; in fifo_open() local
1120 pipe = inode->i_pipe; in fifo_open()
1121 pipe->files++; in fifo_open()
1125 pipe = alloc_pipe_info(); in fifo_open()
1126 if (!pipe) in fifo_open()
1128 pipe->files = 1; in fifo_open()
1133 free_pipe_info(pipe); in fifo_open()
1134 pipe = inode->i_pipe; in fifo_open()
1136 inode->i_pipe = pipe; in fifo_open()
1140 filp->private_data = pipe; in fifo_open()
1141 /* OK, we have a pipe and it's pinned down */ in fifo_open()
1143 mutex_lock(&pipe->mutex); in fifo_open()
1155 pipe->r_counter++; in fifo_open()
1156 if (pipe->readers++ == 0) in fifo_open()
1157 wake_up_partner(pipe); in fifo_open()
1159 if (!is_pipe && !pipe->writers) { in fifo_open()
1163 filp->f_pipe = pipe->w_counter; in fifo_open()
1165 if (wait_for_partner(pipe, &pipe->w_counter)) in fifo_open()
1178 if (!is_pipe && (filp->f_flags & O_NONBLOCK) && !pipe->readers) in fifo_open()
1181 pipe->w_counter++; in fifo_open()
1182 if (!pipe->writers++) in fifo_open()
1183 wake_up_partner(pipe); in fifo_open()
1185 if (!is_pipe && !pipe->readers) { in fifo_open()
1186 if (wait_for_partner(pipe, &pipe->r_counter)) in fifo_open()
1199 pipe->readers++; in fifo_open()
1200 pipe->writers++; in fifo_open()
1201 pipe->r_counter++; in fifo_open()
1202 pipe->w_counter++; in fifo_open()
1203 if (pipe->readers == 1 || pipe->writers == 1) in fifo_open()
1204 wake_up_partner(pipe); in fifo_open()
1213 mutex_unlock(&pipe->mutex); in fifo_open()
1217 if (!--pipe->readers) in fifo_open()
1218 wake_up_interruptible(&pipe->wr_wait); in fifo_open()
1223 if (!--pipe->writers) in fifo_open()
1224 wake_up_interruptible_all(&pipe->rd_wait); in fifo_open()
1229 mutex_unlock(&pipe->mutex); in fifo_open()
1231 put_pipe_info(inode, pipe); in fifo_open()
1247 * Currently we rely on the pipe array holding a power-of-2 number
1255 /* Minimum pipe size, as required by POSIX */ in round_pipe_size()
1263 * Resize the pipe ring to a number of slots.
1265 * Note the pipe can be reduced in capacity, but only if the current
1269 int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) in pipe_resize_ring() argument
1279 spin_lock_irq(&pipe->rd_wait.lock); in pipe_resize_ring()
1280 mask = pipe->ring_size - 1; in pipe_resize_ring()
1281 head = pipe->head; in pipe_resize_ring()
1282 tail = pipe->tail; in pipe_resize_ring()
1286 spin_unlock_irq(&pipe->rd_wait.lock); in pipe_resize_ring()
1292 * The pipe array wraps around, so just start the new one at zero in pipe_resize_ring()
1299 memcpy(bufs, pipe->bufs + t, in pipe_resize_ring()
1302 unsigned int tsize = pipe->ring_size - t; in pipe_resize_ring()
1304 memcpy(bufs + tsize, pipe->bufs, in pipe_resize_ring()
1306 memcpy(bufs, pipe->bufs + t, in pipe_resize_ring()
1314 kfree(pipe->bufs); in pipe_resize_ring()
1315 pipe->bufs = bufs; in pipe_resize_ring()
1316 pipe->ring_size = nr_slots; in pipe_resize_ring()
1317 if (pipe->max_usage > nr_slots) in pipe_resize_ring()
1318 pipe->max_usage = nr_slots; in pipe_resize_ring()
1319 pipe->tail = tail; in pipe_resize_ring()
1320 pipe->head = head; in pipe_resize_ring()
1322 if (!pipe_has_watch_queue(pipe)) { in pipe_resize_ring()
1323 pipe->max_usage = nr_slots; in pipe_resize_ring()
1324 pipe->nr_accounted = nr_slots; in pipe_resize_ring()
1327 spin_unlock_irq(&pipe->rd_wait.lock); in pipe_resize_ring()
1330 wake_up_interruptible(&pipe->wr_wait); in pipe_resize_ring()
1335 * Allocate a new array of pipe buffers and copy the info over. Returns the
1336 * pipe size if successful, or return -ERROR on error.
1338 static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg) in pipe_set_size() argument
1344 if (pipe_has_watch_queue(pipe)) in pipe_set_size()
1354 * If trying to increase the pipe capacity, check that an in pipe_set_size()
1357 * Decreasing the pipe capacity is always permitted, even in pipe_set_size()
1360 if (nr_slots > pipe->max_usage && in pipe_set_size()
1364 user_bufs = account_pipe_buffers(pipe->user, pipe->nr_accounted, nr_slots); in pipe_set_size()
1366 if (nr_slots > pipe->max_usage && in pipe_set_size()
1374 ret = pipe_resize_ring(pipe, nr_slots); in pipe_set_size()
1378 return pipe->max_usage * PAGE_SIZE; in pipe_set_size()
1381 (void) account_pipe_buffers(pipe->user, nr_slots, pipe->nr_accounted); in pipe_set_size()
1387 * not enough to verify that this is a pipe.
1391 struct pipe_inode_info *pipe = file->private_data; in get_pipe_info() local
1393 if (file->f_op != &pipefifo_fops || !pipe) in get_pipe_info()
1395 if (for_splice && pipe_has_watch_queue(pipe)) in get_pipe_info()
1397 return pipe; in get_pipe_info()
1402 struct pipe_inode_info *pipe; in pipe_fcntl() local
1405 pipe = get_pipe_info(file, false); in pipe_fcntl()
1406 if (!pipe) in pipe_fcntl()
1409 mutex_lock(&pipe->mutex); in pipe_fcntl()
1413 ret = pipe_set_size(pipe, arg); in pipe_fcntl()
1416 ret = pipe->max_usage * PAGE_SIZE; in pipe_fcntl()
1423 mutex_unlock(&pipe->mutex); in pipe_fcntl()
1436 * d_name - pipe: will go nicely and kill the special-casing in procfs.
1485 .procname = "pipe-max-size",
1492 .procname = "pipe-user-pages-hard",
1499 .procname = "pipe-user-pages-soft",