2 * "splice": joining two ropes together by interweaving their strands.
4 * This is the "extended pipe" functionality, where a pipe is used as
5 * an arbitrary in-memory buffer. Think of a pipe as a small kernel
6 * buffer that you can use to transfer data from one end to the other.
8 * The traditional unix read/write is extended with a "splice()" operation
9 * that transfers data buffers to or from a pipe buffer.
11 * Named by Larry McVoy, original implementation from Linus, extended by
12 * Jens to support splicing to files, network, direct splicing, etc and
13 * fixing lots of bugs.
15 * Copyright (C) 2005-2006 Jens Axboe <axboe@suse.de>
16 * Copyright (C) 2005-2006 Linus Torvalds <torvalds@osdl.org>
17 * Copyright (C) 2006 Ingo Molnar <mingo@elte.hu>
21 #include <linux/file.h>
22 #include <linux/pagemap.h>
23 #include <linux/pipe_fs_i.h>
24 #include <linux/mm_inline.h>
25 #include <linux/swap.h>
26 #include <linux/writeback.h>
27 #include <linux/buffer_head.h>
28 #include <linux/module.h>
29 #include <linux/syscalls.h>
32 * Passed to the actors
35 unsigned int len
, total_len
; /* current and remaining length */
36 unsigned int flags
; /* splice flags */
37 struct file
*file
; /* file to read/write */
38 loff_t pos
; /* file position */
42 * Attempt to steal a page from a pipe buffer. This should perhaps go into
43 * a vm helper function, it's already simplified quite a bit by the
44 * addition of remove_mapping(). If success is returned, the caller may
45 * attempt to reuse this page for another destination.
47 static int page_cache_pipe_buf_steal(struct pipe_inode_info
*info
,
48 struct pipe_buffer
*buf
)
50 struct page
*page
= buf
->page
;
51 struct address_space
*mapping
= page_mapping(page
);
53 WARN_ON(!PageLocked(page
));
54 WARN_ON(!PageUptodate(page
));
57 * At least for ext2 with nobh option, we need to wait on writeback
58 * completing on this page, since we'll remove it from the pagecache.
59 * Otherwise truncate wont wait on the page, allowing the disk
60 * blocks to be reused by someone else before we actually wrote our
61 * data to them. fs corruption ensues.
63 wait_on_page_writeback(page
);
65 if (PagePrivate(page
))
66 try_to_release_page(page
, mapping_gfp_mask(mapping
));
68 if (!remove_mapping(mapping
, page
))
71 buf
->flags
|= PIPE_BUF_FLAG_STOLEN
| PIPE_BUF_FLAG_LRU
;
75 static void page_cache_pipe_buf_release(struct pipe_inode_info
*info
,
76 struct pipe_buffer
*buf
)
78 page_cache_release(buf
->page
);
80 buf
->flags
&= ~(PIPE_BUF_FLAG_STOLEN
| PIPE_BUF_FLAG_LRU
);
83 static void *page_cache_pipe_buf_map(struct file
*file
,
84 struct pipe_inode_info
*info
,
85 struct pipe_buffer
*buf
)
87 struct page
*page
= buf
->page
;
90 if (!PageUptodate(page
)) {
94 * Page got truncated/unhashed. This will cause a 0-byte
95 * splice, if this is the first page.
103 * Uh oh, read-error from disk.
105 if (!PageUptodate(page
)) {
111 * Page is ok afterall, fall through to mapping.
122 static void page_cache_pipe_buf_unmap(struct pipe_inode_info
*info
,
123 struct pipe_buffer
*buf
)
128 static void page_cache_pipe_buf_get(struct pipe_inode_info
*info
,
129 struct pipe_buffer
*buf
)
131 page_cache_get(buf
->page
);
134 static struct pipe_buf_operations page_cache_pipe_buf_ops
= {
136 .map
= page_cache_pipe_buf_map
,
137 .unmap
= page_cache_pipe_buf_unmap
,
138 .release
= page_cache_pipe_buf_release
,
139 .steal
= page_cache_pipe_buf_steal
,
140 .get
= page_cache_pipe_buf_get
,
144 * Pipe output worker. This sets up our pipe format with the page cache
145 * pipe buffer operations. Otherwise very similar to the regular pipe_writev().
147 static ssize_t
move_to_pipe(struct pipe_inode_info
*pipe
, struct page
**pages
,
148 int nr_pages
, unsigned long offset
,
149 unsigned long len
, unsigned int flags
)
151 int ret
, do_wakeup
, i
;
158 mutex_lock(&pipe
->inode
->i_mutex
);
161 if (!pipe
->readers
) {
162 send_sig(SIGPIPE
, current
, 0);
168 if (pipe
->nrbufs
< PIPE_BUFFERS
) {
169 int newbuf
= (pipe
->curbuf
+ pipe
->nrbufs
) & (PIPE_BUFFERS
- 1);
170 struct pipe_buffer
*buf
= pipe
->bufs
+ newbuf
;
171 struct page
*page
= pages
[i
++];
172 unsigned long this_len
;
174 this_len
= PAGE_CACHE_SIZE
- offset
;
179 buf
->offset
= offset
;
181 buf
->ops
= &page_cache_pipe_buf_ops
;
193 if (pipe
->nrbufs
< PIPE_BUFFERS
)
199 if (flags
& SPLICE_F_NONBLOCK
) {
205 if (signal_pending(current
)) {
213 if (waitqueue_active(&pipe
->wait
))
214 wake_up_interruptible_sync(&pipe
->wait
);
215 kill_fasync(&pipe
->fasync_readers
, SIGIO
, POLL_IN
);
219 pipe
->waiting_writers
++;
221 pipe
->waiting_writers
--;
225 mutex_unlock(&pipe
->inode
->i_mutex
);
229 if (waitqueue_active(&pipe
->wait
))
230 wake_up_interruptible(&pipe
->wait
);
231 kill_fasync(&pipe
->fasync_readers
, SIGIO
, POLL_IN
);
235 page_cache_release(pages
[i
++]);
241 __generic_file_splice_read(struct file
*in
, loff_t
*ppos
,
242 struct pipe_inode_info
*pipe
, size_t len
,
245 struct address_space
*mapping
= in
->f_mapping
;
246 unsigned int offset
, nr_pages
;
247 struct page
*pages
[PIPE_BUFFERS
];
252 index
= *ppos
>> PAGE_CACHE_SHIFT
;
253 offset
= *ppos
& ~PAGE_CACHE_MASK
;
254 nr_pages
= (len
+ offset
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
256 if (nr_pages
> PIPE_BUFFERS
)
257 nr_pages
= PIPE_BUFFERS
;
260 * Initiate read-ahead on this page range. however, don't call into
261 * read-ahead if this is a non-zero offset (we are likely doing small
262 * chunk splice and the page is already there) for a single page.
264 if (!offset
|| nr_pages
> 1)
265 do_page_cache_readahead(mapping
, in
, index
, nr_pages
);
268 * Now fill in the holes:
271 for (i
= 0; i
< nr_pages
; i
++, index
++) {
274 * lookup the page for this index
276 page
= find_get_page(mapping
, index
);
279 * If in nonblock mode then dont block on
280 * readpage (we've kicked readahead so there
281 * will be asynchronous progress):
283 if (flags
& SPLICE_F_NONBLOCK
)
287 * page didn't exist, allocate one
289 page
= page_cache_alloc_cold(mapping
);
293 error
= add_to_page_cache_lru(page
, mapping
, index
,
294 mapping_gfp_mask(mapping
));
295 if (unlikely(error
)) {
296 page_cache_release(page
);
304 * If the page isn't uptodate, we may need to start io on it
306 if (!PageUptodate(page
)) {
310 * page was truncated, stop here. if this isn't the
311 * first page, we'll just complete what we already
314 if (!page
->mapping
) {
316 page_cache_release(page
);
320 * page was already under io and is now done, great
322 if (PageUptodate(page
)) {
329 * need to read in the page
331 error
= mapping
->a_ops
->readpage(in
, page
);
333 if (unlikely(error
)) {
334 page_cache_release(page
);
335 if (error
== AOP_TRUNCATED_PAGE
)
345 return move_to_pipe(pipe
, pages
, i
, offset
, len
, flags
);
351 * generic_file_splice_read - splice data from file to a pipe
352 * @in: file to splice from
353 * @pipe: pipe to splice to
354 * @len: number of bytes to splice
355 * @flags: splice modifier flags
357 * Will read pages from given file and fill them into a pipe.
359 ssize_t
generic_file_splice_read(struct file
*in
, loff_t
*ppos
,
360 struct pipe_inode_info
*pipe
, size_t len
,
370 ret
= __generic_file_splice_read(in
, ppos
, pipe
, len
, flags
);
379 if (!(flags
& SPLICE_F_NONBLOCK
))
391 EXPORT_SYMBOL(generic_file_splice_read
);
394 * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
397 static int pipe_to_sendpage(struct pipe_inode_info
*info
,
398 struct pipe_buffer
*buf
, struct splice_desc
*sd
)
400 struct file
*file
= sd
->file
;
401 loff_t pos
= sd
->pos
;
408 * Sub-optimal, but we are limited by the pipe ->map. We don't
409 * need a kmap'ed buffer here, we just want to make sure we
410 * have the page pinned if the pipe page originates from the
413 ptr
= buf
->ops
->map(file
, info
, buf
);
417 offset
= pos
& ~PAGE_CACHE_MASK
;
418 more
= (sd
->flags
& SPLICE_F_MORE
) || sd
->len
< sd
->total_len
;
420 ret
= file
->f_op
->sendpage(file
, buf
->page
, offset
, sd
->len
, &pos
,more
);
422 buf
->ops
->unmap(info
, buf
);
430 * This is a little more tricky than the file -> pipe splicing. There are
431 * basically three cases:
433 * - Destination page already exists in the address space and there
434 * are users of it. For that case we have no other option that
435 * copying the data. Tough luck.
436 * - Destination page already exists in the address space, but there
437 * are no users of it. Make sure it's uptodate, then drop it. Fall
438 * through to last case.
439 * - Destination page does not exist, we can add the pipe page to
440 * the page cache and avoid the copy.
442 * If asked to move pages to the output file (SPLICE_F_MOVE is set in
443 * sd->flags), we attempt to migrate pages from the pipe to the output
444 * file address space page cache. This is possible if no one else has
445 * the pipe page referenced outside of the pipe and page cache. If
446 * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
447 * a new page in the output file page cache and fill/dirty that.
449 static int pipe_to_file(struct pipe_inode_info
*info
, struct pipe_buffer
*buf
,
450 struct splice_desc
*sd
)
452 struct file
*file
= sd
->file
;
453 struct address_space
*mapping
= file
->f_mapping
;
454 gfp_t gfp_mask
= mapping_gfp_mask(mapping
);
462 * make sure the data in this buffer is uptodate
464 src
= buf
->ops
->map(file
, info
, buf
);
468 index
= sd
->pos
>> PAGE_CACHE_SHIFT
;
469 offset
= sd
->pos
& ~PAGE_CACHE_MASK
;
472 * Reuse buf page, if SPLICE_F_MOVE is set.
474 if (sd
->flags
& SPLICE_F_MOVE
) {
476 * If steal succeeds, buf->page is now pruned from the vm
477 * side (LRU and page cache) and we can reuse it.
479 if (buf
->ops
->steal(info
, buf
))
483 * this will also set the page locked
486 if (add_to_page_cache(page
, mapping
, index
, gfp_mask
))
489 if (!(buf
->flags
& PIPE_BUF_FLAG_LRU
))
494 page
= find_or_create_page(mapping
, index
, gfp_mask
);
499 * If the page is uptodate, it is also locked. If it isn't
500 * uptodate, we can mark it uptodate if we are filling the
501 * full page. Otherwise we need to read it in first...
503 if (!PageUptodate(page
)) {
504 if (sd
->len
< PAGE_CACHE_SIZE
) {
505 ret
= mapping
->a_ops
->readpage(file
, page
);
511 if (!PageUptodate(page
)) {
513 * Page got invalidated, repeat.
515 if (!page
->mapping
) {
517 page_cache_release(page
);
524 WARN_ON(!PageLocked(page
));
525 SetPageUptodate(page
);
530 ret
= mapping
->a_ops
->prepare_write(file
, page
, 0, sd
->len
);
531 if (ret
== AOP_TRUNCATED_PAGE
) {
532 page_cache_release(page
);
537 if (!(buf
->flags
& PIPE_BUF_FLAG_STOLEN
)) {
538 char *dst
= kmap_atomic(page
, KM_USER0
);
540 memcpy(dst
+ offset
, src
+ buf
->offset
, sd
->len
);
541 flush_dcache_page(page
);
542 kunmap_atomic(dst
, KM_USER0
);
545 ret
= mapping
->a_ops
->commit_write(file
, page
, 0, sd
->len
);
546 if (ret
== AOP_TRUNCATED_PAGE
) {
547 page_cache_release(page
);
552 mark_page_accessed(page
);
553 balance_dirty_pages_ratelimited(mapping
);
555 if (!(buf
->flags
& PIPE_BUF_FLAG_STOLEN
)) {
556 page_cache_release(page
);
560 buf
->ops
->unmap(info
, buf
);
564 typedef int (splice_actor
)(struct pipe_inode_info
*, struct pipe_buffer
*,
565 struct splice_desc
*);
568 * Pipe input worker. Most of this logic works like a regular pipe, the
569 * key here is the 'actor' worker passed in that actually moves the data
570 * to the wanted destination. See pipe_to_file/pipe_to_sendpage above.
572 static ssize_t
move_from_pipe(struct pipe_inode_info
*pipe
, struct file
*out
,
573 loff_t
*ppos
, size_t len
, unsigned int flags
,
576 int ret
, do_wakeup
, err
;
577 struct splice_desc sd
;
588 mutex_lock(&pipe
->inode
->i_mutex
);
592 struct pipe_buffer
*buf
= pipe
->bufs
+ pipe
->curbuf
;
593 struct pipe_buf_operations
*ops
= buf
->ops
;
596 if (sd
.len
> sd
.total_len
)
597 sd
.len
= sd
.total_len
;
599 err
= actor(pipe
, buf
, &sd
);
601 if (!ret
&& err
!= -ENODATA
)
608 buf
->offset
+= sd
.len
;
613 ops
->release(pipe
, buf
);
614 pipe
->curbuf
= (pipe
->curbuf
+ 1) & (PIPE_BUFFERS
- 1);
621 sd
.total_len
-= sd
.len
;
630 if (!pipe
->waiting_writers
) {
635 if (flags
& SPLICE_F_NONBLOCK
) {
641 if (signal_pending(current
)) {
649 if (waitqueue_active(&pipe
->wait
))
650 wake_up_interruptible_sync(&pipe
->wait
);
651 kill_fasync(&pipe
->fasync_writers
, SIGIO
, POLL_OUT
);
659 mutex_unlock(&pipe
->inode
->i_mutex
);
663 if (waitqueue_active(&pipe
->wait
))
664 wake_up_interruptible(&pipe
->wait
);
665 kill_fasync(&pipe
->fasync_writers
, SIGIO
, POLL_OUT
);
672 * generic_file_splice_write - splice data from a pipe to a file
674 * @out: file to write to
675 * @len: number of bytes to splice
676 * @flags: splice modifier flags
678 * Will either move or copy pages (determined by @flags options) from
679 * the given pipe inode to the given file.
683 generic_file_splice_write(struct pipe_inode_info
*pipe
, struct file
*out
,
684 loff_t
*ppos
, size_t len
, unsigned int flags
)
686 struct address_space
*mapping
= out
->f_mapping
;
689 ret
= move_from_pipe(pipe
, out
, ppos
, len
, flags
, pipe_to_file
);
692 * If file or inode is SYNC and we actually wrote some data, sync it.
694 if (unlikely((out
->f_flags
& O_SYNC
) || IS_SYNC(mapping
->host
))
696 struct inode
*inode
= mapping
->host
;
699 mutex_lock(&inode
->i_mutex
);
700 err
= generic_osync_inode(mapping
->host
, mapping
,
701 OSYNC_METADATA
|OSYNC_DATA
);
702 mutex_unlock(&inode
->i_mutex
);
711 EXPORT_SYMBOL(generic_file_splice_write
);
714 * generic_splice_sendpage - splice data from a pipe to a socket
716 * @out: socket to write to
717 * @len: number of bytes to splice
718 * @flags: splice modifier flags
720 * Will send @len bytes from the pipe to a network socket. No data copying
724 ssize_t
generic_splice_sendpage(struct pipe_inode_info
*pipe
, struct file
*out
,
725 loff_t
*ppos
, size_t len
, unsigned int flags
)
727 return move_from_pipe(pipe
, out
, ppos
, len
, flags
, pipe_to_sendpage
);
730 EXPORT_SYMBOL(generic_splice_sendpage
);
733 * Attempt to initiate a splice from pipe to file.
735 static long do_splice_from(struct pipe_inode_info
*pipe
, struct file
*out
,
736 loff_t
*ppos
, size_t len
, unsigned int flags
)
740 if (unlikely(!out
->f_op
|| !out
->f_op
->splice_write
))
743 if (unlikely(!(out
->f_mode
& FMODE_WRITE
)))
746 ret
= rw_verify_area(WRITE
, out
, ppos
, len
);
747 if (unlikely(ret
< 0))
750 return out
->f_op
->splice_write(pipe
, out
, ppos
, len
, flags
);
754 * Attempt to initiate a splice from a file to a pipe.
756 static long do_splice_to(struct file
*in
, loff_t
*ppos
,
757 struct pipe_inode_info
*pipe
, size_t len
,
763 if (unlikely(!in
->f_op
|| !in
->f_op
->splice_read
))
766 if (unlikely(!(in
->f_mode
& FMODE_READ
)))
769 ret
= rw_verify_area(READ
, in
, ppos
, len
);
770 if (unlikely(ret
< 0))
773 isize
= i_size_read(in
->f_mapping
->host
);
774 if (unlikely(*ppos
>= isize
))
777 left
= isize
- *ppos
;
778 if (unlikely(left
< len
))
781 return in
->f_op
->splice_read(in
, ppos
, pipe
, len
, flags
);
784 long do_splice_direct(struct file
*in
, loff_t
*ppos
, struct file
*out
,
785 size_t len
, unsigned int flags
)
787 struct pipe_inode_info
*pipe
;
794 * We require the input being a regular file, as we don't want to
795 * randomly drop data for eg socket -> socket splicing. Use the
796 * piped splicing for that!
798 i_mode
= in
->f_dentry
->d_inode
->i_mode
;
799 if (unlikely(!S_ISREG(i_mode
) && !S_ISBLK(i_mode
)))
803 * neither in nor out is a pipe, setup an internal pipe attached to
804 * 'out' and transfer the wanted data from 'in' to 'out' through that
806 pipe
= current
->splice_pipe
;
807 if (unlikely(!pipe
)) {
808 pipe
= alloc_pipe_info(NULL
);
813 * We don't have an immediate reader, but we'll read the stuff
814 * out of the pipe right after the move_to_pipe(). So set
815 * PIPE_READERS appropriately.
819 current
->splice_pipe
= pipe
;
830 size_t read_len
, max_read_len
;
833 * Do at most PIPE_BUFFERS pages worth of transfer:
835 max_read_len
= min(len
, (size_t)(PIPE_BUFFERS
*PAGE_SIZE
));
837 ret
= do_splice_to(in
, ppos
, pipe
, max_read_len
, flags
);
838 if (unlikely(ret
< 0))
844 * NOTE: nonblocking mode only applies to the input. We
845 * must not do the output in nonblocking mode as then we
846 * could get stuck data in the internal pipe:
848 ret
= do_splice_from(pipe
, out
, &out_off
, read_len
,
849 flags
& ~SPLICE_F_NONBLOCK
);
850 if (unlikely(ret
< 0))
857 * In nonblocking mode, if we got back a short read then
858 * that was due to either an IO error or due to the
859 * pagecache entry not being there. In the IO error case
860 * the _next_ splice attempt will produce a clean IO error
861 * return value (not a short read), so in both cases it's
862 * correct to break out of the loop here:
864 if ((flags
& SPLICE_F_NONBLOCK
) && (read_len
< max_read_len
))
868 pipe
->nrbufs
= pipe
->curbuf
= 0;
874 * If we did an incomplete transfer we must release
875 * the pipe buffers in question:
877 for (i
= 0; i
< PIPE_BUFFERS
; i
++) {
878 struct pipe_buffer
*buf
= pipe
->bufs
+ i
;
881 buf
->ops
->release(pipe
, buf
);
885 pipe
->nrbufs
= pipe
->curbuf
= 0;
888 * If we transferred some data, return the number of bytes:
896 EXPORT_SYMBOL(do_splice_direct
);
899 * Determine where to splice to/from.
901 static long do_splice(struct file
*in
, loff_t __user
*off_in
,
902 struct file
*out
, loff_t __user
*off_out
,
903 size_t len
, unsigned int flags
)
905 struct pipe_inode_info
*pipe
;
908 pipe
= in
->f_dentry
->d_inode
->i_pipe
;
913 if (out
->f_op
->llseek
== no_llseek
)
915 if (copy_from_user(&offset
, off_out
, sizeof(loff_t
)))
921 return do_splice_from(pipe
, out
, off
, len
, flags
);
924 pipe
= out
->f_dentry
->d_inode
->i_pipe
;
929 if (in
->f_op
->llseek
== no_llseek
)
931 if (copy_from_user(&offset
, off_in
, sizeof(loff_t
)))
937 return do_splice_to(in
, off
, pipe
, len
, flags
);
943 asmlinkage
long sys_splice(int fd_in
, loff_t __user
*off_in
,
944 int fd_out
, loff_t __user
*off_out
,
945 size_t len
, unsigned int flags
)
948 struct file
*in
, *out
;
949 int fput_in
, fput_out
;
955 in
= fget_light(fd_in
, &fput_in
);
957 if (in
->f_mode
& FMODE_READ
) {
958 out
= fget_light(fd_out
, &fput_out
);
960 if (out
->f_mode
& FMODE_WRITE
)
961 error
= do_splice(in
, off_in
,
964 fput_light(out
, fput_out
);
968 fput_light(in
, fput_in
);
975 * Link contents of ipipe to opipe.
977 static int link_pipe(struct pipe_inode_info
*ipipe
,
978 struct pipe_inode_info
*opipe
,
979 size_t len
, unsigned int flags
)
981 struct pipe_buffer
*ibuf
, *obuf
;
982 int ret
= 0, do_wakeup
= 0, i
;
985 * Potential ABBA deadlock, work around it by ordering lock
986 * grabbing by inode address. Otherwise two different processes
987 * could deadlock (one doing tee from A -> B, the other from B -> A).
989 if (ipipe
->inode
< opipe
->inode
) {
990 mutex_lock(&ipipe
->inode
->i_mutex
);
991 mutex_lock(&opipe
->inode
->i_mutex
);
993 mutex_lock(&opipe
->inode
->i_mutex
);
994 mutex_lock(&ipipe
->inode
->i_mutex
);
998 if (!opipe
->readers
) {
999 send_sig(SIGPIPE
, current
, 0);
1004 if (ipipe
->nrbufs
- i
) {
1005 ibuf
= ipipe
->bufs
+ ((ipipe
->curbuf
+ i
) & (PIPE_BUFFERS
- 1));
1008 * If we have room, fill this buffer
1010 if (opipe
->nrbufs
< PIPE_BUFFERS
) {
1011 int nbuf
= (opipe
->curbuf
+ opipe
->nrbufs
) & (PIPE_BUFFERS
- 1);
1014 * Get a reference to this pipe buffer,
1015 * so we can copy the contents over.
1017 ibuf
->ops
->get(ipipe
, ibuf
);
1019 obuf
= opipe
->bufs
+ nbuf
;
1022 if (obuf
->len
> len
)
1032 if (opipe
->nrbufs
< PIPE_BUFFERS
)
1037 * We have input available, but no output room.
1038 * If we already copied data, return that.
1040 if (flags
& SPLICE_F_NONBLOCK
) {
1045 if (signal_pending(current
)) {
1052 if (waitqueue_active(&opipe
->wait
))
1053 wake_up_interruptible(&opipe
->wait
);
1054 kill_fasync(&opipe
->fasync_readers
, SIGIO
, POLL_IN
);
1058 opipe
->waiting_writers
++;
1060 opipe
->waiting_writers
--;
1065 * No input buffers, do the usual checks for available
1066 * writers and blocking and wait if necessary
1068 if (!ipipe
->writers
)
1070 if (!ipipe
->waiting_writers
) {
1074 if (flags
& SPLICE_F_NONBLOCK
) {
1079 if (signal_pending(current
)) {
1085 if (waitqueue_active(&ipipe
->wait
))
1086 wake_up_interruptible_sync(&ipipe
->wait
);
1087 kill_fasync(&ipipe
->fasync_writers
, SIGIO
, POLL_OUT
);
1092 mutex_unlock(&ipipe
->inode
->i_mutex
);
1093 mutex_unlock(&opipe
->inode
->i_mutex
);
1097 if (waitqueue_active(&opipe
->wait
))
1098 wake_up_interruptible(&opipe
->wait
);
1099 kill_fasync(&opipe
->fasync_readers
, SIGIO
, POLL_IN
);
1106 * This is a tee(1) implementation that works on pipes. It doesn't copy
1107 * any data, it simply references the 'in' pages on the 'out' pipe.
1108 * The 'flags' used are the SPLICE_F_* variants, currently the only
1109 * applicable one is SPLICE_F_NONBLOCK.
1111 static long do_tee(struct file
*in
, struct file
*out
, size_t len
,
1114 struct pipe_inode_info
*ipipe
= in
->f_dentry
->d_inode
->i_pipe
;
1115 struct pipe_inode_info
*opipe
= out
->f_dentry
->d_inode
->i_pipe
;
1118 * Link ipipe to the two output pipes, consuming as we go along.
1121 return link_pipe(ipipe
, opipe
, len
, flags
);
1126 asmlinkage
long sys_tee(int fdin
, int fdout
, size_t len
, unsigned int flags
)
1135 in
= fget_light(fdin
, &fput_in
);
1137 if (in
->f_mode
& FMODE_READ
) {
1139 struct file
*out
= fget_light(fdout
, &fput_out
);
1142 if (out
->f_mode
& FMODE_WRITE
)
1143 error
= do_tee(in
, out
, len
, flags
);
1144 fput_light(out
, fput_out
);
1147 fput_light(in
, fput_in
);