cregit-Linux how code gets into the kernel

Release 4.11 fs/read_write.c

Directory: fs
/*
 *  linux/fs/read_write.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/sched/xacct.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include "internal.h"

#include <linux/uaccess.h>
#include <asm/unistd.h>


const struct file_operations generic_ro_fops = {
	.llseek		= generic_file_llseek,
	.read_iter	= generic_file_read_iter,
	.mmap		= generic_file_readonly_mmap,
	.splice_read	= generic_file_splice_read,
};


EXPORT_SYMBOL(generic_ro_fops);




static inline int unsigned_offsets(struct file *file)
{
	return file->f_mode & FMODE_UNSIGNED_OFFSET;
}


Contributors
PersonTokensPropCommitsCommitProp
Kamezawa Hiroyuki1789.47%150.00%


Al Viro210.53%150.00%


Total19100.00%2100.00%



/**
 * vfs_setpos - update the file offset for lseek
 * @file:       file structure in question
 * @offset:     file offset to seek to
 * @maxsize:    maximum file size
 *
 * This is a low-level filesystem helper for updating the file offset to
 * the value specified by @offset if the given offset is valid and it is
 * not equal to the current file offset.
 *
 * Return the specified offset on success and -EINVAL on invalid offset.
 */



loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
	if (offset < 0 && !unsigned_offsets(file))
		return -EINVAL;
	if (offset > maxsize)
		return -EINVAL;

	if (offset != file->f_pos) {
		file->f_pos = offset;
		file->f_version = 0;
	}
	return offset;
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds3552.24%111.11%


Kamezawa Hiroyuki1116.42%111.11%


Christoph Hellwig710.45%111.11%


Andi Kleen710.45%111.11%


Al Viro22.99%111.11%


Robert Love22.99%111.11%


Josef Bacik11.49%111.11%


Andrew Morton11.49%111.11%


Jie Liu11.49%111.11%


Total67100.00%9100.00%




EXPORT_SYMBOL(vfs_setpos);

/**
 * generic_file_llseek_size - generic llseek implementation for regular files
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 * @size:       max size of this file in file system
 * @eof:        offset used for SEEK_END position
 *
 * This is a variant of generic_file_llseek that allows passing in a custom
 * maximum file size and a custom EOF position, for e.g. hashed directories
 *
 * Synchronization:
 * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
 * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
 * read/writes behave like SEEK_SET against seeks.
 */


loff_t

generic_file_llseek_size(struct file *file, loff_t offset, int whence,
		loff_t maxsize, loff_t eof)
{
	switch (whence) {
	case SEEK_END:
		offset += eof;
		break;
	case SEEK_CUR:
		/*
                 * Here we special-case the lseek(fd, 0, SEEK_CUR)
                 * position-querying operation.  Avoid rewriting the "same"
                 * f_pos value back to the file because a concurrent read(),
                 * write() or lseek() might have altered it
                 */
		if (offset == 0)
			return file->f_pos;
		/*
                 * f_lock protects against read/modify/write race with other
                 * SEEK_CURs. Note that parallel writes and reads behave
                 * like SEEK_SET.
                 */
		spin_lock(&file->f_lock);
		offset = vfs_setpos(file, file->f_pos + offset, maxsize);
		spin_unlock(&file->f_lock);
		return offset;
	case SEEK_DATA:
		/*
                 * In the generic case the entire file is data, so as long as
                 * offset isn't at the end of the file then the offset is data.
                 */
		if (offset >= eof)
			return -ENXIO;
		break;
	case SEEK_HOLE:
		/*
                 * There is a virtual hole at the end of the file, so as long as
                 * offset isn't i_size or larger, return i_size.
                 */
		if (offset >= eof)
			return -ENXIO;
		offset = eof;
		break;
	}

	return vfs_setpos(file, offset, maxsize);
}

Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen9573.08%342.86%


Robert Love2418.46%114.29%


Eric Sandeen75.38%114.29%


Jie Liu21.54%114.29%


Andrew Morton21.54%114.29%


Total130100.00%7100.00%




EXPORT_SYMBOL(generic_file_llseek_size);

/**
 * generic_file_llseek - generic llseek implementation for regular files
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 *
 * This is a generic implemenation of ->llseek useable for all normal local
 * filesystems.  It just updates the file offset to the value specified by
 * @offset and @whence.
 */



loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
{
	struct inode *inode = file->f_mapping->host;

	return generic_file_llseek_size(file, offset, whence,
					inode->i_sb->s_maxbytes,
					i_size_read(inode));
}

Contributors
PersonTokensPropCommitsCommitProp
Andi Kleen3981.25%240.00%


Eric Sandeen510.42%120.00%


Andrew Morton24.17%120.00%


Linus Torvalds24.17%120.00%


Total48100.00%5100.00%




EXPORT_SYMBOL(generic_file_llseek);

/**
 * fixed_size_llseek - llseek implementation for fixed-sized devices
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 * @size:       size of the file
 *
 */



loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
{
	switch (whence) {
	case SEEK_SET: case SEEK_CUR: case SEEK_END:
		return generic_file_llseek_size(file, offset, whence,
						size, size);
	default:
		return -EINVAL;
	}
}

Contributors
PersonTokensPropCommitsCommitProp
Al Viro53100.00%1100.00%


Total53100.00%1100.00%




EXPORT_SYMBOL(fixed_size_llseek);

/**
 * no_seek_end_llseek - llseek implementation for fixed-sized devices
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 *
 */



loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
{
	switch (whence) {
	case SEEK_SET: case SEEK_CUR:
		return generic_file_llseek_size(file, offset, whence,
						OFFSET_MAX, 0);
	default:
		return -EINVAL;
	}
}

Contributors
PersonTokensPropCommitsCommitProp
Al Viro4697.87%150.00%


Wouter van Kesteren12.13%150.00%


Total47100.00%2100.00%




EXPORT_SYMBOL(no_seek_end_llseek);

/**
 * no_seek_end_llseek_size - llseek implementation for fixed-sized devices
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 * @size:       maximal offset allowed
 *
 */



loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
{
	switch (whence) {
	case SEEK_SET: case SEEK_CUR:
		return generic_file_llseek_size(file, offset, whence,
						size, 0);
	default:
		return -EINVAL;
	}
}

Contributors
PersonTokensPropCommitsCommitProp
Al Viro50100.00%1100.00%


Total50100.00%1100.00%




EXPORT_SYMBOL(no_seek_end_llseek_size);

/**
 * noop_llseek - No Operation Performed llseek implementation
 * @file:       file structure to seek on
 * @offset:     file offset to seek to
 * @whence:     type of seek
 *
 * This is an implementation of ->llseek useable for the rare special case when
 * userspace expects the seek to succeed but the (device) file is actually not
 * able to perform the seek. In this case you use noop_llseek() instead of
 * falling back to the default implementation of ->llseek.
 */



loff_t noop_llseek(struct file *file, loff_t offset, int whence)
{
	return file->f_pos;
}

Contributors
PersonTokensPropCommitsCommitProp
Jan Blunck2095.24%150.00%


Andrew Morton14.76%150.00%


Total21100.00%2100.00%




EXPORT_SYMBOL(noop_llseek);




loff_t no_llseek(struct file *file, loff_t offset, int whence)
{
	return -ESPIPE;
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds1995.00%150.00%


Andrew Morton15.00%150.00%


Total20100.00%2100.00%




EXPORT_SYMBOL(no_llseek);




loff_t default_llseek(struct file *file, loff_t offset, int whence)
{
	struct inode *inode = file_inode(file);
	loff_t retval;

	inode_lock(inode);
	switch (whence) {
		case SEEK_END:
			offset += i_size_read(inode);
			break;
		case SEEK_CUR:
			if (offset == 0) {
				retval = file->f_pos;
				goto out;
			}
			offset += file->f_pos;
			break;
		case SEEK_DATA:
			/*
                         * In the generic case the entire file is data, so as
                         * long as offset isn't at the end of the file then the
                         * offset is data.
                         */
			if (offset >= inode->i_size) {
				retval = -ENXIO;
				goto out;
			}
			break;
		case SEEK_HOLE:
			/*
                         * There is a virtual hole at the end of the file, so
                         * as long as offset isn't i_size or larger, return
                         * i_size.
                         */
			if (offset >= inode->i_size) {
				retval = -ENXIO;
				goto out;
			}
			offset = inode->i_size;
			break;
	}
	retval = -EINVAL;
	if (offset >= 0 || unsigned_offsets(file)) {
		if (offset != file->f_pos) {
			file->f_pos = offset;
			file->f_version = 0;
		}
		retval = offset;
	}
out:
	inode_unlock(inode);
	return retval;
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)7741.85%422.22%


Josef Bacik4725.54%15.56%


Alain Knaff1910.33%15.56%


Dan Carpenter168.70%15.56%


Al Viro63.26%316.67%


Andrew Morton63.26%316.67%


Arnd Bergmann42.17%15.56%


Kamezawa Hiroyuki42.17%15.56%


Chris Snook21.09%15.56%


Linus Torvalds21.09%15.56%


David Sterba10.54%15.56%


Total184100.00%18100.00%




EXPORT_SYMBOL(default_llseek);




loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
{
	loff_t (*fn)(struct file *, loff_t, int);

	fn = no_llseek;
	if (file->f_mode & FMODE_LSEEK) {
		if (file->f_op->llseek)
			fn = file->f_op->llseek;
	}
	return fn(file, offset, whence);
}

Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)5577.46%555.56%


Linus Torvalds1318.31%222.22%


Andrew Morton22.82%111.11%


Neil Brown11.41%111.11%


Total71100.00%9100.00%




EXPORT_SYMBOL(vfs_llseek);


SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
{
	off_t retval;
	struct fd f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	retval = -EINVAL;
	if (whence <= SEEK_MAX) {
		loff_t res = vfs_llseek(f.file, offset, whence);
		retval = res;
		if (res != (loff_t)retval)
			retval = -EOVERFLOW;	/* LFS: should only happen on 32 bit platforms */
	}
	fdput_pos(f);
	return retval;
}

#ifdef CONFIG_COMPAT

COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
{
	return sys_lseek(fd, offset, whence);
}
#endif

#ifdef __ARCH_WANT_SYS_LLSEEK

SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
		unsigned long, offset_low, loff_t __user *, result,
		unsigned int, whence)
{
	int retval;
	struct fd f = fdget_pos(fd);
	loff_t offset;

	if (!f.file)
		return -EBADF;

	retval = -EINVAL;
	if (whence > SEEK_MAX)
		goto out_putf;

	offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
			whence);

	retval = (int)offset;
	if (offset >= 0) {
		retval = -EFAULT;
		if (!copy_to_user(result, &offset, sizeof(offset)))
			retval = 0;
	}
out_putf:
	fdput_pos(f);
	return retval;
}
#endif




ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
{
	struct kiocb kiocb;
	ssize_t ret;

	if (!file->f_op->read_iter)
		return -EINVAL;

	init_sync_kiocb(&kiocb, file);
	kiocb.ki_pos = *ppos;

	iter->type |= READ;
	ret = call_read_iter(file, &kiocb, iter);
	BUG_ON(ret == -EIOCBQUEUED);
	if (ret > 0)
		*ppos = kiocb.ki_pos;
	return ret;
}

Contributors
PersonTokensPropCommitsCommitProp
Christoph Hellwig9396.88%266.67%


Miklos Szeredi33.12%133.33%


Total96100.00%3100.00%




EXPORT_SYMBOL(vfs_iter_read);




ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
{
	struct kiocb kiocb;
	ssize_t ret;

	if (!file->f_op->write_iter)
		return -EINVAL;

	init_sync_kiocb(&kiocb, file);
	kiocb.ki_pos = *ppos;

	iter->type |= WRITE;
	ret = call_write_iter(file, &kiocb, iter);
	BUG_ON(ret == -EIOCBQUEUED);
	if (ret > 0)
		*ppos = kiocb.ki_pos;
	return ret;
}

Contributors
PersonTokensPropCommitsCommitProp
Christoph Hellwig9396.88%266.67%


Miklos Szeredi33.12%133.33%


Total96100.00%3100.00%




EXPORT_SYMBOL(vfs_iter_write);




int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
	struct inode *inode;
	loff_t pos;
	int retval = -EINVAL;

	inode = file_inode(file);
	if (unlikely((ssize_t) count < 0))
		return retval;
	pos = *ppos;
	if (unlikely(pos < 0)) {
		if (!unsigned_offsets(file))
			return retval;
		if (count >= -pos) /* both values are in 0..LLONG_MAX */
			return -EOVERFLOW;
	} else if (unlikely((loff_t) (pos + count) < 0)) {
		if (!unsigned_offsets(file))
			return retval;
	}

	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
		retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
				read_write == READ ? F_RDLCK : F_WRLCK);
		if (retval < 0)
			return retval;
	}
	return security_file_permission(file,
				read_write == READ ? MAY_READ : MAY_WRITE);
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds9650.53%426.67%


Al Viro4121.58%426.67%


James Morris2613.68%16.67%


Christoph Hellwig126.32%16.67%


Kamezawa Hiroyuki63.16%16.67%


Eric Dumazet42.11%16.67%


Jens Axboe31.58%16.67%


Jeff Layton10.53%16.67%


Pavel Emelyanov10.53%16.67%


Total190100.00%15100.00%






static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
	struct iovec iov = { .iov_base = buf, .iov_len = len };
	struct kiocb kiocb;
	struct iov_iter iter;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	iov_iter_init(&iter, READ, &iov, 1, len);

	ret = call_read_iter(filp, &kiocb, &iter);
	BUG_ON(ret == -EIOCBQUEUED);
	*ppos = kiocb.ki_pos;
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Al Viro10493.69%250.00%


Christoph Hellwig43.60%125.00%


Miklos Szeredi32.70%125.00%


Total111100.00%4100.00%






ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
		   loff_t *pos)
{
	if (file->f_op->read)
		return file->f_op->read(file, buf, count, pos);
	else if (file->f_op->read_iter)
		return new_sync_read(file, buf, count, pos);
	else
		return -EINVAL;
}

Contributors
PersonTokensPropCommitsCommitProp
Dmitry Kasatkin6793.06%150.00%


Al Viro56.94%150.00%


Total72100.00%2100.00%




EXPORT_SYMBOL(__vfs_read);




ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
	ssize_t ret;

	if (!(file->f_mode & FMODE_READ))
		return -EBADF;
	if (!(file->f_mode & FMODE_CAN_READ))
		return -EINVAL;
	if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
		return -EFAULT;

	ret = rw_verify_area(READ, file, pos, count);
	if (!ret) {
		if (count > MAX_RW_COUNT)
			count =  MAX_RW_COUNT;
		ret = __vfs_read(file, buf, count, pos);
		if (ret > 0) {
			fsnotify_access(file);
			add_rchar(current, ret);
		}
		inc_syscr(current);
	}

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Christoph Hellwig3826.21%15.56%


Linus Torvalds (pre-git)3624.83%633.33%


Al Viro3020.69%316.67%


Linus Torvalds2517.24%422.22%


Alexey Dobriyan74.83%15.56%


Jay Lan74.83%15.56%


Robert Love10.69%15.56%


Dmitry Kasatkin10.69%15.56%


Total145100.00%18100.00%




EXPORT_SYMBOL(vfs_read);




static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
	struct kiocb kiocb;
	struct iov_iter iter;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	iov_iter_init(&iter, WRITE, &iov, 1, len);

	ret = call_write_iter(filp, &kiocb, &iter);
	BUG_ON(ret == -EIOCBQUEUED);
	if (ret > 0)
		*ppos = kiocb.ki_pos;
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Christoph Hellwig6149.59%222.22%


Al Viro2822.76%333.33%


Badari Pulavarty2318.70%111.11%


Neil Brown75.69%111.11%


Miklos Szeredi32.44%111.11%


Linus Torvalds10.81%111.11%


Total123100.00%9100.00%






ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
		    loff_t *pos)
{
	if (file->f_op->write)
		return file->f_op->write(file, p, count, pos);
	else if (file->f_op->write_iter)
		return new_sync_write(file, p, count, pos);
	else
		return -EINVAL;
}

Contributors
PersonTokensPropCommitsCommitProp
Al Viro73100.00%1100.00%


Total73100.00%1100.00%




EXPORT_SYMBOL(__vfs_write);




ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
{
	mm_segment_t old_fs;
	const char __user *p;
	ssize_t ret;

	if (!(file->f_mode & FMODE_CAN_WRITE))
		return -EINVAL;

	old_fs = get_fs();
	set_fs(get_ds());
	p = (__force const char __user *)buf;
	if (count > MAX_RW_COUNT)
		count =  MAX_RW_COUNT;
	ret = __vfs_write(file, p, count, pos);
	set_fs(old_fs);
	if (ret > 0) {
		fsnotify_modify(file);
		add_wchar(current, ret);
	}
	inc_syscw(current);
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Al Viro127100.00%5100.00%


Total127100.00%5100.00%




EXPORT_SYMBOL(__kernel_write);




ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
{
	ssize_t ret;

	if (!(file->f_mode & FMODE_WRITE))
		return -EBADF;
	if (!(file->f_mode & FMODE_CAN_WRITE))
		return -EINVAL;
	if (unlikely(!access_ok(VERIFY_READ, buf, count)))
		return -EFAULT;

	ret = rw_verify_area(WRITE, file, pos, count);
	if (!ret) {
		if (count > MAX_RW_COUNT)
			count =  MAX_RW_COUNT;
		file_start_write(file);
		ret = __vfs_write(file, buf, count, pos);
		if (ret > 0) {
			fsnotify_modify(file);
			add_wchar(current, ret);
		}
		inc_syscw(current);
		file_end_write(file);
	}

	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Neil Brown7145.51%17.14%


Al Viro3421.79%535.71%


Linus Torvalds2516.03%428.57%


Christoph Hellwig117.05%17.14%


Alexey Dobriyan74.49%17.14%


Jay Lan74.49%17.14%


Robert Love10.64%17.14%


Total156100.00%14100.00%




EXPORT_SYMBOL(vfs_write);




static inline loff_t file_pos_read(struct file *file)
{
	return file->f_pos;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds17100.00%1100.00%


Total17100.00%1100.00%






static inline void file_pos_write(struct file *file, loff_t pos)
{
	file->f_pos = pos;
}


Contributors
PersonTokensPropCommitsCommitProp
Linus Torvalds21100.00%1100.00%


Total21100.00%1100.00%




SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
{
	struct fd f = fdget_pos(fd);
	ssize_t ret = -EBADF;

	if (f.file) {
		loff_t pos = file_pos_read(f.file);
		ret = vfs_read(f.file, buf, count, &pos);
		if (ret >= 0)
			file_pos_write(f.file, pos);
		fdput_pos(f);
	}
	return ret;
}


SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
		size_t, count)
{
	struct fd f = fdget_pos(fd);
	ssize_t ret = -EBADF;

	if (f.file) {
		loff_t pos = file_pos_read(f.file);
		ret = vfs_write(f.file, buf, count, &pos);
		if (ret >= 0)
			file_pos_write(f.file, pos);
		fdput_pos(f);
	}

	return ret;
}


SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
			size_t, count, loff_t, pos)
{
	struct fd f;
	ssize_t ret = -EBADF;

	if (pos < 0)
		return -EINVAL;

	f = fdget(fd);
	if (f.file) {
		ret = -ESPIPE;
		if (f.file->f_mode & FMODE_PREAD)
			ret = vfs_read(f.file, buf, count, &pos);
		fdput(f);
	}

	return ret;
}


SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
			 size_t, count, loff_t, pos)
{
	struct fd f;
	ssize_t ret = -EBADF;

	if (pos < 0)
		return -EINVAL;

	f = fdget(fd);
	if (f.file) {
		ret = -ESPIPE;
		if (f.file->f_mode & FMODE_PWRITE)  
			ret = vfs_write(f.file, buf, count, &pos);
		fdput(f);
	}

	return ret;
}

/*
 * Reduce an iovec's length in-place.  Return the resulting number of segments
 */



unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
{
	unsigned long seg = 0;
	size_t len = 0;

	while (seg < nr_segs) {
		seg++;
		if (len + iov->iov_len >= to) {
			iov->iov_len = to - len;
			break;
		}
		len += iov->iov_len;
		iov++;
	}
	return seg;
}

Contributors
PersonTokensPropCommitsCommitProp
Andrew Morton73100.00%1100.00%


Total73100.00%1100.00%




EXPORT_SYMBOL(iov_shorten);




static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
		loff_t *ppos, int type, int flags)
{
	struct kiocb kiocb;
	ssize_t ret;

	if (flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC))
		return -EOPNOTSUPP;

	init_sync_kiocb(&kiocb, filp);
	if (flags & RWF_HIPRI)
		kiocb.ki_flags |= IOCB_HIPRI;
	if (flags & RWF_DSYNC)
		kiocb.ki_flags |= IOCB_DSYNC;
	if (flags & RWF_SYNC)
		kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
	kiocb.ki_pos = *ppos;

	if (type == READ)
		ret = call_read_iter(filp, &kiocb, iter);
	else
		ret = call_write_iter(filp, &kiocb, iter);
	BUG_ON(ret == -EIOCBQUEUED);
	*ppos = kiocb.ki_pos;
	return ret;
}


Contributors
PersonTokensPropCommitsCommitProp
Al Viro6844.16%225.00%


Christoph Hellwig6240.26%450.00%


Miklos Szeredi2415.58%225.00%


Total154100.00%