xref: /openbmc/linux/fs/read_write.c (revision 92a2c6b2)
1 /*
2  *  linux/fs/read_write.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 #include <linux/slab.h>
8 #include <linux/stat.h>
9 #include <linux/fcntl.h>
10 #include <linux/file.h>
11 #include <linux/uio.h>
12 #include <linux/aio.h>
13 #include <linux/fsnotify.h>
14 #include <linux/security.h>
15 #include <linux/export.h>
16 #include <linux/syscalls.h>
17 #include <linux/pagemap.h>
18 #include <linux/splice.h>
19 #include <linux/compat.h>
20 #include "internal.h"
21 
22 #include <asm/uaccess.h>
23 #include <asm/unistd.h>
24 
25 typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
26 typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *,
27 		unsigned long, loff_t);
28 typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *);
29 
30 const struct file_operations generic_ro_fops = {
31 	.llseek		= generic_file_llseek,
32 	.read		= new_sync_read,
33 	.read_iter	= generic_file_read_iter,
34 	.mmap		= generic_file_readonly_mmap,
35 	.splice_read	= generic_file_splice_read,
36 };
37 
38 EXPORT_SYMBOL(generic_ro_fops);
39 
40 static inline int unsigned_offsets(struct file *file)
41 {
42 	return file->f_mode & FMODE_UNSIGNED_OFFSET;
43 }
44 
45 /**
46  * vfs_setpos - update the file offset for lseek
47  * @file:	file structure in question
48  * @offset:	file offset to seek to
49  * @maxsize:	maximum file size
50  *
51  * This is a low-level filesystem helper for updating the file offset to
52  * the value specified by @offset if the given offset is valid and it is
53  * not equal to the current file offset.
54  *
55  * Return the specified offset on success and -EINVAL on invalid offset.
56  */
57 loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
58 {
59 	if (offset < 0 && !unsigned_offsets(file))
60 		return -EINVAL;
61 	if (offset > maxsize)
62 		return -EINVAL;
63 
64 	if (offset != file->f_pos) {
65 		file->f_pos = offset;
66 		file->f_version = 0;
67 	}
68 	return offset;
69 }
70 EXPORT_SYMBOL(vfs_setpos);
71 
72 /**
73  * generic_file_llseek_size - generic llseek implementation for regular files
74  * @file:	file structure to seek on
75  * @offset:	file offset to seek to
76  * @whence:	type of seek
77  * @size:	max size of this file in file system
78  * @eof:	offset used for SEEK_END position
79  *
80  * This is a variant of generic_file_llseek that allows passing in a custom
81  * maximum file size and a custom EOF position, for e.g. hashed directories
82  *
83  * Synchronization:
84  * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
85  * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
86  * read/writes behave like SEEK_SET against seeks.
87  */
88 loff_t
89 generic_file_llseek_size(struct file *file, loff_t offset, int whence,
90 		loff_t maxsize, loff_t eof)
91 {
92 	switch (whence) {
93 	case SEEK_END:
94 		offset += eof;
95 		break;
96 	case SEEK_CUR:
97 		/*
98 		 * Here we special-case the lseek(fd, 0, SEEK_CUR)
99 		 * position-querying operation.  Avoid rewriting the "same"
100 		 * f_pos value back to the file because a concurrent read(),
101 		 * write() or lseek() might have altered it
102 		 */
103 		if (offset == 0)
104 			return file->f_pos;
105 		/*
106 		 * f_lock protects against read/modify/write race with other
107 		 * SEEK_CURs. Note that parallel writes and reads behave
108 		 * like SEEK_SET.
109 		 */
110 		spin_lock(&file->f_lock);
111 		offset = vfs_setpos(file, file->f_pos + offset, maxsize);
112 		spin_unlock(&file->f_lock);
113 		return offset;
114 	case SEEK_DATA:
115 		/*
116 		 * In the generic case the entire file is data, so as long as
117 		 * offset isn't at the end of the file then the offset is data.
118 		 */
119 		if (offset >= eof)
120 			return -ENXIO;
121 		break;
122 	case SEEK_HOLE:
123 		/*
124 		 * There is a virtual hole at the end of the file, so as long as
125 		 * offset isn't i_size or larger, return i_size.
126 		 */
127 		if (offset >= eof)
128 			return -ENXIO;
129 		offset = eof;
130 		break;
131 	}
132 
133 	return vfs_setpos(file, offset, maxsize);
134 }
135 EXPORT_SYMBOL(generic_file_llseek_size);
136 
137 /**
138  * generic_file_llseek - generic llseek implementation for regular files
139  * @file:	file structure to seek on
140  * @offset:	file offset to seek to
141  * @whence:	type of seek
142  *
143  * This is a generic implemenation of ->llseek useable for all normal local
144  * filesystems.  It just updates the file offset to the value specified by
145  * @offset and @whence.
146  */
147 loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
148 {
149 	struct inode *inode = file->f_mapping->host;
150 
151 	return generic_file_llseek_size(file, offset, whence,
152 					inode->i_sb->s_maxbytes,
153 					i_size_read(inode));
154 }
155 EXPORT_SYMBOL(generic_file_llseek);
156 
157 /**
158  * fixed_size_llseek - llseek implementation for fixed-sized devices
159  * @file:	file structure to seek on
160  * @offset:	file offset to seek to
161  * @whence:	type of seek
162  * @size:	size of the file
163  *
164  */
165 loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
166 {
167 	switch (whence) {
168 	case SEEK_SET: case SEEK_CUR: case SEEK_END:
169 		return generic_file_llseek_size(file, offset, whence,
170 						size, size);
171 	default:
172 		return -EINVAL;
173 	}
174 }
175 EXPORT_SYMBOL(fixed_size_llseek);
176 
177 /**
178  * noop_llseek - No Operation Performed llseek implementation
179  * @file:	file structure to seek on
180  * @offset:	file offset to seek to
181  * @whence:	type of seek
182  *
183  * This is an implementation of ->llseek useable for the rare special case when
184  * userspace expects the seek to succeed but the (device) file is actually not
185  * able to perform the seek. In this case you use noop_llseek() instead of
186  * falling back to the default implementation of ->llseek.
187  */
188 loff_t noop_llseek(struct file *file, loff_t offset, int whence)
189 {
190 	return file->f_pos;
191 }
192 EXPORT_SYMBOL(noop_llseek);
193 
194 loff_t no_llseek(struct file *file, loff_t offset, int whence)
195 {
196 	return -ESPIPE;
197 }
198 EXPORT_SYMBOL(no_llseek);
199 
200 loff_t default_llseek(struct file *file, loff_t offset, int whence)
201 {
202 	struct inode *inode = file_inode(file);
203 	loff_t retval;
204 
205 	mutex_lock(&inode->i_mutex);
206 	switch (whence) {
207 		case SEEK_END:
208 			offset += i_size_read(inode);
209 			break;
210 		case SEEK_CUR:
211 			if (offset == 0) {
212 				retval = file->f_pos;
213 				goto out;
214 			}
215 			offset += file->f_pos;
216 			break;
217 		case SEEK_DATA:
218 			/*
219 			 * In the generic case the entire file is data, so as
220 			 * long as offset isn't at the end of the file then the
221 			 * offset is data.
222 			 */
223 			if (offset >= inode->i_size) {
224 				retval = -ENXIO;
225 				goto out;
226 			}
227 			break;
228 		case SEEK_HOLE:
229 			/*
230 			 * There is a virtual hole at the end of the file, so
231 			 * as long as offset isn't i_size or larger, return
232 			 * i_size.
233 			 */
234 			if (offset >= inode->i_size) {
235 				retval = -ENXIO;
236 				goto out;
237 			}
238 			offset = inode->i_size;
239 			break;
240 	}
241 	retval = -EINVAL;
242 	if (offset >= 0 || unsigned_offsets(file)) {
243 		if (offset != file->f_pos) {
244 			file->f_pos = offset;
245 			file->f_version = 0;
246 		}
247 		retval = offset;
248 	}
249 out:
250 	mutex_unlock(&inode->i_mutex);
251 	return retval;
252 }
253 EXPORT_SYMBOL(default_llseek);
254 
255 loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
256 {
257 	loff_t (*fn)(struct file *, loff_t, int);
258 
259 	fn = no_llseek;
260 	if (file->f_mode & FMODE_LSEEK) {
261 		if (file->f_op->llseek)
262 			fn = file->f_op->llseek;
263 	}
264 	return fn(file, offset, whence);
265 }
266 EXPORT_SYMBOL(vfs_llseek);
267 
268 static inline struct fd fdget_pos(int fd)
269 {
270 	return __to_fd(__fdget_pos(fd));
271 }
272 
273 static inline void fdput_pos(struct fd f)
274 {
275 	if (f.flags & FDPUT_POS_UNLOCK)
276 		mutex_unlock(&f.file->f_pos_lock);
277 	fdput(f);
278 }
279 
280 SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
281 {
282 	off_t retval;
283 	struct fd f = fdget_pos(fd);
284 	if (!f.file)
285 		return -EBADF;
286 
287 	retval = -EINVAL;
288 	if (whence <= SEEK_MAX) {
289 		loff_t res = vfs_llseek(f.file, offset, whence);
290 		retval = res;
291 		if (res != (loff_t)retval)
292 			retval = -EOVERFLOW;	/* LFS: should only happen on 32 bit platforms */
293 	}
294 	fdput_pos(f);
295 	return retval;
296 }
297 
298 #ifdef CONFIG_COMPAT
299 COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
300 {
301 	return sys_lseek(fd, offset, whence);
302 }
303 #endif
304 
305 #ifdef __ARCH_WANT_SYS_LLSEEK
306 SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
307 		unsigned long, offset_low, loff_t __user *, result,
308 		unsigned int, whence)
309 {
310 	int retval;
311 	struct fd f = fdget_pos(fd);
312 	loff_t offset;
313 
314 	if (!f.file)
315 		return -EBADF;
316 
317 	retval = -EINVAL;
318 	if (whence > SEEK_MAX)
319 		goto out_putf;
320 
321 	offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
322 			whence);
323 
324 	retval = (int)offset;
325 	if (offset >= 0) {
326 		retval = -EFAULT;
327 		if (!copy_to_user(result, &offset, sizeof(offset)))
328 			retval = 0;
329 	}
330 out_putf:
331 	fdput_pos(f);
332 	return retval;
333 }
334 #endif
335 
336 ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
337 {
338 	struct kiocb kiocb;
339 	ssize_t ret;
340 
341 	if (!file->f_op->read_iter)
342 		return -EINVAL;
343 
344 	init_sync_kiocb(&kiocb, file);
345 	kiocb.ki_pos = *ppos;
346 	kiocb.ki_nbytes = iov_iter_count(iter);
347 
348 	iter->type |= READ;
349 	ret = file->f_op->read_iter(&kiocb, iter);
350 	if (ret == -EIOCBQUEUED)
351 		ret = wait_on_sync_kiocb(&kiocb);
352 
353 	if (ret > 0)
354 		*ppos = kiocb.ki_pos;
355 	return ret;
356 }
357 EXPORT_SYMBOL(vfs_iter_read);
358 
359 ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
360 {
361 	struct kiocb kiocb;
362 	ssize_t ret;
363 
364 	if (!file->f_op->write_iter)
365 		return -EINVAL;
366 
367 	init_sync_kiocb(&kiocb, file);
368 	kiocb.ki_pos = *ppos;
369 	kiocb.ki_nbytes = iov_iter_count(iter);
370 
371 	iter->type |= WRITE;
372 	ret = file->f_op->write_iter(&kiocb, iter);
373 	if (ret == -EIOCBQUEUED)
374 		ret = wait_on_sync_kiocb(&kiocb);
375 
376 	if (ret > 0)
377 		*ppos = kiocb.ki_pos;
378 	return ret;
379 }
380 EXPORT_SYMBOL(vfs_iter_write);
381 
382 /*
383  * rw_verify_area doesn't like huge counts. We limit
384  * them to something that fits in "int" so that others
385  * won't have to do range checks all the time.
386  */
387 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
388 {
389 	struct inode *inode;
390 	loff_t pos;
391 	int retval = -EINVAL;
392 
393 	inode = file_inode(file);
394 	if (unlikely((ssize_t) count < 0))
395 		return retval;
396 	pos = *ppos;
397 	if (unlikely(pos < 0)) {
398 		if (!unsigned_offsets(file))
399 			return retval;
400 		if (count >= -pos) /* both values are in 0..LLONG_MAX */
401 			return -EOVERFLOW;
402 	} else if (unlikely((loff_t) (pos + count) < 0)) {
403 		if (!unsigned_offsets(file))
404 			return retval;
405 	}
406 
407 	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
408 		retval = locks_mandatory_area(
409 			read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
410 			inode, file, pos, count);
411 		if (retval < 0)
412 			return retval;
413 	}
414 	retval = security_file_permission(file,
415 				read_write == READ ? MAY_READ : MAY_WRITE);
416 	if (retval)
417 		return retval;
418 	return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
419 }
420 
421 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
422 {
423 	struct iovec iov = { .iov_base = buf, .iov_len = len };
424 	struct kiocb kiocb;
425 	ssize_t ret;
426 
427 	init_sync_kiocb(&kiocb, filp);
428 	kiocb.ki_pos = *ppos;
429 	kiocb.ki_nbytes = len;
430 
431 	ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
432 	if (-EIOCBQUEUED == ret)
433 		ret = wait_on_sync_kiocb(&kiocb);
434 	*ppos = kiocb.ki_pos;
435 	return ret;
436 }
437 
438 EXPORT_SYMBOL(do_sync_read);
439 
440 ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
441 {
442 	struct iovec iov = { .iov_base = buf, .iov_len = len };
443 	struct kiocb kiocb;
444 	struct iov_iter iter;
445 	ssize_t ret;
446 
447 	init_sync_kiocb(&kiocb, filp);
448 	kiocb.ki_pos = *ppos;
449 	kiocb.ki_nbytes = len;
450 	iov_iter_init(&iter, READ, &iov, 1, len);
451 
452 	ret = filp->f_op->read_iter(&kiocb, &iter);
453 	if (-EIOCBQUEUED == ret)
454 		ret = wait_on_sync_kiocb(&kiocb);
455 	*ppos = kiocb.ki_pos;
456 	return ret;
457 }
458 
459 EXPORT_SYMBOL(new_sync_read);
460 
461 ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
462 		   loff_t *pos)
463 {
464 	ssize_t ret;
465 
466 	if (file->f_op->read)
467 		ret = file->f_op->read(file, buf, count, pos);
468 	else if (file->f_op->aio_read)
469 		ret = do_sync_read(file, buf, count, pos);
470 	else if (file->f_op->read_iter)
471 		ret = new_sync_read(file, buf, count, pos);
472 	else
473 		ret = -EINVAL;
474 
475 	return ret;
476 }
477 
478 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
479 {
480 	ssize_t ret;
481 
482 	if (!(file->f_mode & FMODE_READ))
483 		return -EBADF;
484 	if (!(file->f_mode & FMODE_CAN_READ))
485 		return -EINVAL;
486 	if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
487 		return -EFAULT;
488 
489 	ret = rw_verify_area(READ, file, pos, count);
490 	if (ret >= 0) {
491 		count = ret;
492 		ret = __vfs_read(file, buf, count, pos);
493 		if (ret > 0) {
494 			fsnotify_access(file);
495 			add_rchar(current, ret);
496 		}
497 		inc_syscr(current);
498 	}
499 
500 	return ret;
501 }
502 
503 EXPORT_SYMBOL(vfs_read);
504 
505 ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
506 {
507 	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
508 	struct kiocb kiocb;
509 	ssize_t ret;
510 
511 	init_sync_kiocb(&kiocb, filp);
512 	kiocb.ki_pos = *ppos;
513 	kiocb.ki_nbytes = len;
514 
515 	ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
516 	if (-EIOCBQUEUED == ret)
517 		ret = wait_on_sync_kiocb(&kiocb);
518 	*ppos = kiocb.ki_pos;
519 	return ret;
520 }
521 
522 EXPORT_SYMBOL(do_sync_write);
523 
524 ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
525 {
526 	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
527 	struct kiocb kiocb;
528 	struct iov_iter iter;
529 	ssize_t ret;
530 
531 	init_sync_kiocb(&kiocb, filp);
532 	kiocb.ki_pos = *ppos;
533 	kiocb.ki_nbytes = len;
534 	iov_iter_init(&iter, WRITE, &iov, 1, len);
535 
536 	ret = filp->f_op->write_iter(&kiocb, &iter);
537 	if (-EIOCBQUEUED == ret)
538 		ret = wait_on_sync_kiocb(&kiocb);
539 	*ppos = kiocb.ki_pos;
540 	return ret;
541 }
542 
543 EXPORT_SYMBOL(new_sync_write);
544 
545 ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
546 {
547 	mm_segment_t old_fs;
548 	const char __user *p;
549 	ssize_t ret;
550 
551 	if (!(file->f_mode & FMODE_CAN_WRITE))
552 		return -EINVAL;
553 
554 	old_fs = get_fs();
555 	set_fs(get_ds());
556 	p = (__force const char __user *)buf;
557 	if (count > MAX_RW_COUNT)
558 		count =  MAX_RW_COUNT;
559 	if (file->f_op->write)
560 		ret = file->f_op->write(file, p, count, pos);
561 	else if (file->f_op->aio_write)
562 		ret = do_sync_write(file, p, count, pos);
563 	else
564 		ret = new_sync_write(file, p, count, pos);
565 	set_fs(old_fs);
566 	if (ret > 0) {
567 		fsnotify_modify(file);
568 		add_wchar(current, ret);
569 	}
570 	inc_syscw(current);
571 	return ret;
572 }
573 
574 EXPORT_SYMBOL(__kernel_write);
575 
576 ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
577 {
578 	ssize_t ret;
579 
580 	if (!(file->f_mode & FMODE_WRITE))
581 		return -EBADF;
582 	if (!(file->f_mode & FMODE_CAN_WRITE))
583 		return -EINVAL;
584 	if (unlikely(!access_ok(VERIFY_READ, buf, count)))
585 		return -EFAULT;
586 
587 	ret = rw_verify_area(WRITE, file, pos, count);
588 	if (ret >= 0) {
589 		count = ret;
590 		file_start_write(file);
591 		if (file->f_op->write)
592 			ret = file->f_op->write(file, buf, count, pos);
593 		else if (file->f_op->aio_write)
594 			ret = do_sync_write(file, buf, count, pos);
595 		else
596 			ret = new_sync_write(file, buf, count, pos);
597 		if (ret > 0) {
598 			fsnotify_modify(file);
599 			add_wchar(current, ret);
600 		}
601 		inc_syscw(current);
602 		file_end_write(file);
603 	}
604 
605 	return ret;
606 }
607 
608 EXPORT_SYMBOL(vfs_write);
609 
610 static inline loff_t file_pos_read(struct file *file)
611 {
612 	return file->f_pos;
613 }
614 
615 static inline void file_pos_write(struct file *file, loff_t pos)
616 {
617 	file->f_pos = pos;
618 }
619 
620 SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
621 {
622 	struct fd f = fdget_pos(fd);
623 	ssize_t ret = -EBADF;
624 
625 	if (f.file) {
626 		loff_t pos = file_pos_read(f.file);
627 		ret = vfs_read(f.file, buf, count, &pos);
628 		if (ret >= 0)
629 			file_pos_write(f.file, pos);
630 		fdput_pos(f);
631 	}
632 	return ret;
633 }
634 
635 SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
636 		size_t, count)
637 {
638 	struct fd f = fdget_pos(fd);
639 	ssize_t ret = -EBADF;
640 
641 	if (f.file) {
642 		loff_t pos = file_pos_read(f.file);
643 		ret = vfs_write(f.file, buf, count, &pos);
644 		if (ret >= 0)
645 			file_pos_write(f.file, pos);
646 		fdput_pos(f);
647 	}
648 
649 	return ret;
650 }
651 
652 SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
653 			size_t, count, loff_t, pos)
654 {
655 	struct fd f;
656 	ssize_t ret = -EBADF;
657 
658 	if (pos < 0)
659 		return -EINVAL;
660 
661 	f = fdget(fd);
662 	if (f.file) {
663 		ret = -ESPIPE;
664 		if (f.file->f_mode & FMODE_PREAD)
665 			ret = vfs_read(f.file, buf, count, &pos);
666 		fdput(f);
667 	}
668 
669 	return ret;
670 }
671 
672 SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
673 			 size_t, count, loff_t, pos)
674 {
675 	struct fd f;
676 	ssize_t ret = -EBADF;
677 
678 	if (pos < 0)
679 		return -EINVAL;
680 
681 	f = fdget(fd);
682 	if (f.file) {
683 		ret = -ESPIPE;
684 		if (f.file->f_mode & FMODE_PWRITE)
685 			ret = vfs_write(f.file, buf, count, &pos);
686 		fdput(f);
687 	}
688 
689 	return ret;
690 }
691 
692 /*
693  * Reduce an iovec's length in-place.  Return the resulting number of segments
694  */
695 unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
696 {
697 	unsigned long seg = 0;
698 	size_t len = 0;
699 
700 	while (seg < nr_segs) {
701 		seg++;
702 		if (len + iov->iov_len >= to) {
703 			iov->iov_len = to - len;
704 			break;
705 		}
706 		len += iov->iov_len;
707 		iov++;
708 	}
709 	return seg;
710 }
711 EXPORT_SYMBOL(iov_shorten);
712 
713 static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iovec *iov,
714 		unsigned long nr_segs, size_t len, loff_t *ppos, iter_fn_t fn)
715 {
716 	struct kiocb kiocb;
717 	struct iov_iter iter;
718 	ssize_t ret;
719 
720 	init_sync_kiocb(&kiocb, filp);
721 	kiocb.ki_pos = *ppos;
722 	kiocb.ki_nbytes = len;
723 
724 	iov_iter_init(&iter, rw, iov, nr_segs, len);
725 	ret = fn(&kiocb, &iter);
726 	if (ret == -EIOCBQUEUED)
727 		ret = wait_on_sync_kiocb(&kiocb);
728 	*ppos = kiocb.ki_pos;
729 	return ret;
730 }
731 
732 static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
733 		unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
734 {
735 	struct kiocb kiocb;
736 	ssize_t ret;
737 
738 	init_sync_kiocb(&kiocb, filp);
739 	kiocb.ki_pos = *ppos;
740 	kiocb.ki_nbytes = len;
741 
742 	ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
743 	if (ret == -EIOCBQUEUED)
744 		ret = wait_on_sync_kiocb(&kiocb);
745 	*ppos = kiocb.ki_pos;
746 	return ret;
747 }
748 
749 /* Do it by hand, with file-ops */
750 static ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
751 		unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
752 {
753 	struct iovec *vector = iov;
754 	ssize_t ret = 0;
755 
756 	while (nr_segs > 0) {
757 		void __user *base;
758 		size_t len;
759 		ssize_t nr;
760 
761 		base = vector->iov_base;
762 		len = vector->iov_len;
763 		vector++;
764 		nr_segs--;
765 
766 		nr = fn(filp, base, len, ppos);
767 
768 		if (nr < 0) {
769 			if (!ret)
770 				ret = nr;
771 			break;
772 		}
773 		ret += nr;
774 		if (nr != len)
775 			break;
776 	}
777 
778 	return ret;
779 }
780 
781 /* A write operation does a read from user space and vice versa */
782 #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
783 
784 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
785 			      unsigned long nr_segs, unsigned long fast_segs,
786 			      struct iovec *fast_pointer,
787 			      struct iovec **ret_pointer)
788 {
789 	unsigned long seg;
790 	ssize_t ret;
791 	struct iovec *iov = fast_pointer;
792 
793 	/*
794 	 * SuS says "The readv() function *may* fail if the iovcnt argument
795 	 * was less than or equal to 0, or greater than {IOV_MAX}.  Linux has
796 	 * traditionally returned zero for zero segments, so...
797 	 */
798 	if (nr_segs == 0) {
799 		ret = 0;
800 		goto out;
801 	}
802 
803 	/*
804 	 * First get the "struct iovec" from user memory and
805 	 * verify all the pointers
806 	 */
807 	if (nr_segs > UIO_MAXIOV) {
808 		ret = -EINVAL;
809 		goto out;
810 	}
811 	if (nr_segs > fast_segs) {
812 		iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
813 		if (iov == NULL) {
814 			ret = -ENOMEM;
815 			goto out;
816 		}
817 	}
818 	if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
819 		ret = -EFAULT;
820 		goto out;
821 	}
822 
823 	/*
824 	 * According to the Single Unix Specification we should return EINVAL
825 	 * if an element length is < 0 when cast to ssize_t or if the
826 	 * total length would overflow the ssize_t return value of the
827 	 * system call.
828 	 *
829 	 * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
830 	 * overflow case.
831 	 */
832 	ret = 0;
833 	for (seg = 0; seg < nr_segs; seg++) {
834 		void __user *buf = iov[seg].iov_base;
835 		ssize_t len = (ssize_t)iov[seg].iov_len;
836 
837 		/* see if we we're about to use an invalid len or if
838 		 * it's about to overflow ssize_t */
839 		if (len < 0) {
840 			ret = -EINVAL;
841 			goto out;
842 		}
843 		if (type >= 0
844 		    && unlikely(!access_ok(vrfy_dir(type), buf, len))) {
845 			ret = -EFAULT;
846 			goto out;
847 		}
848 		if (len > MAX_RW_COUNT - ret) {
849 			len = MAX_RW_COUNT - ret;
850 			iov[seg].iov_len = len;
851 		}
852 		ret += len;
853 	}
854 out:
855 	*ret_pointer = iov;
856 	return ret;
857 }
858 
859 static ssize_t do_readv_writev(int type, struct file *file,
860 			       const struct iovec __user * uvector,
861 			       unsigned long nr_segs, loff_t *pos)
862 {
863 	size_t tot_len;
864 	struct iovec iovstack[UIO_FASTIOV];
865 	struct iovec *iov = iovstack;
866 	ssize_t ret;
867 	io_fn_t fn;
868 	iov_fn_t fnv;
869 	iter_fn_t iter_fn;
870 
871 	ret = rw_copy_check_uvector(type, uvector, nr_segs,
872 				    ARRAY_SIZE(iovstack), iovstack, &iov);
873 	if (ret <= 0)
874 		goto out;
875 
876 	tot_len = ret;
877 	ret = rw_verify_area(type, file, pos, tot_len);
878 	if (ret < 0)
879 		goto out;
880 
881 	fnv = NULL;
882 	if (type == READ) {
883 		fn = file->f_op->read;
884 		fnv = file->f_op->aio_read;
885 		iter_fn = file->f_op->read_iter;
886 	} else {
887 		fn = (io_fn_t)file->f_op->write;
888 		fnv = file->f_op->aio_write;
889 		iter_fn = file->f_op->write_iter;
890 		file_start_write(file);
891 	}
892 
893 	if (iter_fn)
894 		ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
895 						pos, iter_fn);
896 	else if (fnv)
897 		ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
898 						pos, fnv);
899 	else
900 		ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
901 
902 	if (type != READ)
903 		file_end_write(file);
904 
905 out:
906 	if (iov != iovstack)
907 		kfree(iov);
908 	if ((ret + (type == READ)) > 0) {
909 		if (type == READ)
910 			fsnotify_access(file);
911 		else
912 			fsnotify_modify(file);
913 	}
914 	return ret;
915 }
916 
917 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
918 		  unsigned long vlen, loff_t *pos)
919 {
920 	if (!(file->f_mode & FMODE_READ))
921 		return -EBADF;
922 	if (!(file->f_mode & FMODE_CAN_READ))
923 		return -EINVAL;
924 
925 	return do_readv_writev(READ, file, vec, vlen, pos);
926 }
927 
928 EXPORT_SYMBOL(vfs_readv);
929 
930 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
931 		   unsigned long vlen, loff_t *pos)
932 {
933 	if (!(file->f_mode & FMODE_WRITE))
934 		return -EBADF;
935 	if (!(file->f_mode & FMODE_CAN_WRITE))
936 		return -EINVAL;
937 
938 	return do_readv_writev(WRITE, file, vec, vlen, pos);
939 }
940 
941 EXPORT_SYMBOL(vfs_writev);
942 
943 SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
944 		unsigned long, vlen)
945 {
946 	struct fd f = fdget_pos(fd);
947 	ssize_t ret = -EBADF;
948 
949 	if (f.file) {
950 		loff_t pos = file_pos_read(f.file);
951 		ret = vfs_readv(f.file, vec, vlen, &pos);
952 		if (ret >= 0)
953 			file_pos_write(f.file, pos);
954 		fdput_pos(f);
955 	}
956 
957 	if (ret > 0)
958 		add_rchar(current, ret);
959 	inc_syscr(current);
960 	return ret;
961 }
962 
963 SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
964 		unsigned long, vlen)
965 {
966 	struct fd f = fdget_pos(fd);
967 	ssize_t ret = -EBADF;
968 
969 	if (f.file) {
970 		loff_t pos = file_pos_read(f.file);
971 		ret = vfs_writev(f.file, vec, vlen, &pos);
972 		if (ret >= 0)
973 			file_pos_write(f.file, pos);
974 		fdput_pos(f);
975 	}
976 
977 	if (ret > 0)
978 		add_wchar(current, ret);
979 	inc_syscw(current);
980 	return ret;
981 }
982 
983 static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
984 {
985 #define HALF_LONG_BITS (BITS_PER_LONG / 2)
986 	return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
987 }
988 
989 SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
990 		unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
991 {
992 	loff_t pos = pos_from_hilo(pos_h, pos_l);
993 	struct fd f;
994 	ssize_t ret = -EBADF;
995 
996 	if (pos < 0)
997 		return -EINVAL;
998 
999 	f = fdget(fd);
1000 	if (f.file) {
1001 		ret = -ESPIPE;
1002 		if (f.file->f_mode & FMODE_PREAD)
1003 			ret = vfs_readv(f.file, vec, vlen, &pos);
1004 		fdput(f);
1005 	}
1006 
1007 	if (ret > 0)
1008 		add_rchar(current, ret);
1009 	inc_syscr(current);
1010 	return ret;
1011 }
1012 
1013 SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
1014 		unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
1015 {
1016 	loff_t pos = pos_from_hilo(pos_h, pos_l);
1017 	struct fd f;
1018 	ssize_t ret = -EBADF;
1019 
1020 	if (pos < 0)
1021 		return -EINVAL;
1022 
1023 	f = fdget(fd);
1024 	if (f.file) {
1025 		ret = -ESPIPE;
1026 		if (f.file->f_mode & FMODE_PWRITE)
1027 			ret = vfs_writev(f.file, vec, vlen, &pos);
1028 		fdput(f);
1029 	}
1030 
1031 	if (ret > 0)
1032 		add_wchar(current, ret);
1033 	inc_syscw(current);
1034 	return ret;
1035 }
1036 
1037 #ifdef CONFIG_COMPAT
1038 
1039 static ssize_t compat_do_readv_writev(int type, struct file *file,
1040 			       const struct compat_iovec __user *uvector,
1041 			       unsigned long nr_segs, loff_t *pos)
1042 {
1043 	compat_ssize_t tot_len;
1044 	struct iovec iovstack[UIO_FASTIOV];
1045 	struct iovec *iov = iovstack;
1046 	ssize_t ret;
1047 	io_fn_t fn;
1048 	iov_fn_t fnv;
1049 	iter_fn_t iter_fn;
1050 
1051 	ret = compat_rw_copy_check_uvector(type, uvector, nr_segs,
1052 					       UIO_FASTIOV, iovstack, &iov);
1053 	if (ret <= 0)
1054 		goto out;
1055 
1056 	tot_len = ret;
1057 	ret = rw_verify_area(type, file, pos, tot_len);
1058 	if (ret < 0)
1059 		goto out;
1060 
1061 	fnv = NULL;
1062 	if (type == READ) {
1063 		fn = file->f_op->read;
1064 		fnv = file->f_op->aio_read;
1065 		iter_fn = file->f_op->read_iter;
1066 	} else {
1067 		fn = (io_fn_t)file->f_op->write;
1068 		fnv = file->f_op->aio_write;
1069 		iter_fn = file->f_op->write_iter;
1070 		file_start_write(file);
1071 	}
1072 
1073 	if (iter_fn)
1074 		ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
1075 						pos, iter_fn);
1076 	else if (fnv)
1077 		ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
1078 						pos, fnv);
1079 	else
1080 		ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
1081 
1082 	if (type != READ)
1083 		file_end_write(file);
1084 
1085 out:
1086 	if (iov != iovstack)
1087 		kfree(iov);
1088 	if ((ret + (type == READ)) > 0) {
1089 		if (type == READ)
1090 			fsnotify_access(file);
1091 		else
1092 			fsnotify_modify(file);
1093 	}
1094 	return ret;
1095 }
1096 
1097 static size_t compat_readv(struct file *file,
1098 			   const struct compat_iovec __user *vec,
1099 			   unsigned long vlen, loff_t *pos)
1100 {
1101 	ssize_t ret = -EBADF;
1102 
1103 	if (!(file->f_mode & FMODE_READ))
1104 		goto out;
1105 
1106 	ret = -EINVAL;
1107 	if (!(file->f_mode & FMODE_CAN_READ))
1108 		goto out;
1109 
1110 	ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
1111 
1112 out:
1113 	if (ret > 0)
1114 		add_rchar(current, ret);
1115 	inc_syscr(current);
1116 	return ret;
1117 }
1118 
1119 COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
1120 		const struct compat_iovec __user *,vec,
1121 		compat_ulong_t, vlen)
1122 {
1123 	struct fd f = fdget_pos(fd);
1124 	ssize_t ret;
1125 	loff_t pos;
1126 
1127 	if (!f.file)
1128 		return -EBADF;
1129 	pos = f.file->f_pos;
1130 	ret = compat_readv(f.file, vec, vlen, &pos);
1131 	if (ret >= 0)
1132 		f.file->f_pos = pos;
1133 	fdput_pos(f);
1134 	return ret;
1135 }
1136 
1137 static long __compat_sys_preadv64(unsigned long fd,
1138 				  const struct compat_iovec __user *vec,
1139 				  unsigned long vlen, loff_t pos)
1140 {
1141 	struct fd f;
1142 	ssize_t ret;
1143 
1144 	if (pos < 0)
1145 		return -EINVAL;
1146 	f = fdget(fd);
1147 	if (!f.file)
1148 		return -EBADF;
1149 	ret = -ESPIPE;
1150 	if (f.file->f_mode & FMODE_PREAD)
1151 		ret = compat_readv(f.file, vec, vlen, &pos);
1152 	fdput(f);
1153 	return ret;
1154 }
1155 
1156 #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
1157 COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
1158 		const struct compat_iovec __user *,vec,
1159 		unsigned long, vlen, loff_t, pos)
1160 {
1161 	return __compat_sys_preadv64(fd, vec, vlen, pos);
1162 }
1163 #endif
1164 
1165 COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
1166 		const struct compat_iovec __user *,vec,
1167 		compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
1168 {
1169 	loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1170 
1171 	return __compat_sys_preadv64(fd, vec, vlen, pos);
1172 }
1173 
1174 static size_t compat_writev(struct file *file,
1175 			    const struct compat_iovec __user *vec,
1176 			    unsigned long vlen, loff_t *pos)
1177 {
1178 	ssize_t ret = -EBADF;
1179 
1180 	if (!(file->f_mode & FMODE_WRITE))
1181 		goto out;
1182 
1183 	ret = -EINVAL;
1184 	if (!(file->f_mode & FMODE_CAN_WRITE))
1185 		goto out;
1186 
1187 	ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
1188 
1189 out:
1190 	if (ret > 0)
1191 		add_wchar(current, ret);
1192 	inc_syscw(current);
1193 	return ret;
1194 }
1195 
1196 COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
1197 		const struct compat_iovec __user *, vec,
1198 		compat_ulong_t, vlen)
1199 {
1200 	struct fd f = fdget_pos(fd);
1201 	ssize_t ret;
1202 	loff_t pos;
1203 
1204 	if (!f.file)
1205 		return -EBADF;
1206 	pos = f.file->f_pos;
1207 	ret = compat_writev(f.file, vec, vlen, &pos);
1208 	if (ret >= 0)
1209 		f.file->f_pos = pos;
1210 	fdput_pos(f);
1211 	return ret;
1212 }
1213 
1214 static long __compat_sys_pwritev64(unsigned long fd,
1215 				   const struct compat_iovec __user *vec,
1216 				   unsigned long vlen, loff_t pos)
1217 {
1218 	struct fd f;
1219 	ssize_t ret;
1220 
1221 	if (pos < 0)
1222 		return -EINVAL;
1223 	f = fdget(fd);
1224 	if (!f.file)
1225 		return -EBADF;
1226 	ret = -ESPIPE;
1227 	if (f.file->f_mode & FMODE_PWRITE)
1228 		ret = compat_writev(f.file, vec, vlen, &pos);
1229 	fdput(f);
1230 	return ret;
1231 }
1232 
1233 #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
1234 COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
1235 		const struct compat_iovec __user *,vec,
1236 		unsigned long, vlen, loff_t, pos)
1237 {
1238 	return __compat_sys_pwritev64(fd, vec, vlen, pos);
1239 }
1240 #endif
1241 
1242 COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
1243 		const struct compat_iovec __user *,vec,
1244 		compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
1245 {
1246 	loff_t pos = ((loff_t)pos_high << 32) | pos_low;
1247 
1248 	return __compat_sys_pwritev64(fd, vec, vlen, pos);
1249 }
1250 #endif
1251 
1252 static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
1253 		  	   size_t count, loff_t max)
1254 {
1255 	struct fd in, out;
1256 	struct inode *in_inode, *out_inode;
1257 	loff_t pos;
1258 	loff_t out_pos;
1259 	ssize_t retval;
1260 	int fl;
1261 
1262 	/*
1263 	 * Get input file, and verify that it is ok..
1264 	 */
1265 	retval = -EBADF;
1266 	in = fdget(in_fd);
1267 	if (!in.file)
1268 		goto out;
1269 	if (!(in.file->f_mode & FMODE_READ))
1270 		goto fput_in;
1271 	retval = -ESPIPE;
1272 	if (!ppos) {
1273 		pos = in.file->f_pos;
1274 	} else {
1275 		pos = *ppos;
1276 		if (!(in.file->f_mode & FMODE_PREAD))
1277 			goto fput_in;
1278 	}
1279 	retval = rw_verify_area(READ, in.file, &pos, count);
1280 	if (retval < 0)
1281 		goto fput_in;
1282 	count = retval;
1283 
1284 	/*
1285 	 * Get output file, and verify that it is ok..
1286 	 */
1287 	retval = -EBADF;
1288 	out = fdget(out_fd);
1289 	if (!out.file)
1290 		goto fput_in;
1291 	if (!(out.file->f_mode & FMODE_WRITE))
1292 		goto fput_out;
1293 	retval = -EINVAL;
1294 	in_inode = file_inode(in.file);
1295 	out_inode = file_inode(out.file);
1296 	out_pos = out.file->f_pos;
1297 	retval = rw_verify_area(WRITE, out.file, &out_pos, count);
1298 	if (retval < 0)
1299 		goto fput_out;
1300 	count = retval;
1301 
1302 	if (!max)
1303 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
1304 
1305 	if (unlikely(pos + count > max)) {
1306 		retval = -EOVERFLOW;
1307 		if (pos >= max)
1308 			goto fput_out;
1309 		count = max - pos;
1310 	}
1311 
1312 	fl = 0;
1313 #if 0
1314 	/*
1315 	 * We need to debate whether we can enable this or not. The
1316 	 * man page documents EAGAIN return for the output at least,
1317 	 * and the application is arguably buggy if it doesn't expect
1318 	 * EAGAIN on a non-blocking file descriptor.
1319 	 */
1320 	if (in.file->f_flags & O_NONBLOCK)
1321 		fl = SPLICE_F_NONBLOCK;
1322 #endif
1323 	file_start_write(out.file);
1324 	retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
1325 	file_end_write(out.file);
1326 
1327 	if (retval > 0) {
1328 		add_rchar(current, retval);
1329 		add_wchar(current, retval);
1330 		fsnotify_access(in.file);
1331 		fsnotify_modify(out.file);
1332 		out.file->f_pos = out_pos;
1333 		if (ppos)
1334 			*ppos = pos;
1335 		else
1336 			in.file->f_pos = pos;
1337 	}
1338 
1339 	inc_syscr(current);
1340 	inc_syscw(current);
1341 	if (pos > max)
1342 		retval = -EOVERFLOW;
1343 
1344 fput_out:
1345 	fdput(out);
1346 fput_in:
1347 	fdput(in);
1348 out:
1349 	return retval;
1350 }
1351 
1352 SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
1353 {
1354 	loff_t pos;
1355 	off_t off;
1356 	ssize_t ret;
1357 
1358 	if (offset) {
1359 		if (unlikely(get_user(off, offset)))
1360 			return -EFAULT;
1361 		pos = off;
1362 		ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1363 		if (unlikely(put_user(pos, offset)))
1364 			return -EFAULT;
1365 		return ret;
1366 	}
1367 
1368 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
1369 }
1370 
1371 SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
1372 {
1373 	loff_t pos;
1374 	ssize_t ret;
1375 
1376 	if (offset) {
1377 		if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1378 			return -EFAULT;
1379 		ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1380 		if (unlikely(put_user(pos, offset)))
1381 			return -EFAULT;
1382 		return ret;
1383 	}
1384 
1385 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
1386 }
1387 
1388 #ifdef CONFIG_COMPAT
1389 COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
1390 		compat_off_t __user *, offset, compat_size_t, count)
1391 {
1392 	loff_t pos;
1393 	off_t off;
1394 	ssize_t ret;
1395 
1396 	if (offset) {
1397 		if (unlikely(get_user(off, offset)))
1398 			return -EFAULT;
1399 		pos = off;
1400 		ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
1401 		if (unlikely(put_user(pos, offset)))
1402 			return -EFAULT;
1403 		return ret;
1404 	}
1405 
1406 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
1407 }
1408 
1409 COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
1410 		compat_loff_t __user *, offset, compat_size_t, count)
1411 {
1412 	loff_t pos;
1413 	ssize_t ret;
1414 
1415 	if (offset) {
1416 		if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
1417 			return -EFAULT;
1418 		ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
1419 		if (unlikely(put_user(pos, offset)))
1420 			return -EFAULT;
1421 		return ret;
1422 	}
1423 
1424 	return do_sendfile(out_fd, in_fd, NULL, count, 0);
1425 }
1426 #endif
1427