Commit 5dcdc43e authored by Jiufei Xue's avatar Jiufei Xue Committed by Miklos Szeredi
Browse files

vfs: add vfs_iocb_iter_[read|write] helper functions 



This doesn't cause any behavior changes and will be used by overlay async
IO implementation.

Signed-off-by: default avatarJiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 13464165

fs/read_write.c

+56 −0
Original line number Diff line number Diff line
@@ -939,6 +939,34 @@ static ssize_t do_iter_read(struct file *file, struct iov_iter *iter, 
	return ret;

}



ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,

			   struct iov_iter *iter)

{

	size_t tot_len;

	ssize_t ret = 0;



	if (!file->f_op->read_iter)

		return -EINVAL;

	if (!(file->f_mode & FMODE_READ))

		return -EBADF;

	if (!(file->f_mode & FMODE_CAN_READ))

		return -EINVAL;



	tot_len = iov_iter_count(iter);

	if (!tot_len)

		goto out;

	ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);

	if (ret < 0)

		return ret;



	ret = call_read_iter(file, iocb, iter);

out:

	if (ret >= 0)

		fsnotify_access(file);

	return ret;

}

EXPORT_SYMBOL(vfs_iocb_iter_read);



ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,

		rwf_t flags)

{
@@ -975,6 +1003,34 @@ static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, 
	return ret;

}



ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,

			    struct iov_iter *iter)

{

	size_t tot_len;

	ssize_t ret = 0;



	if (!file->f_op->write_iter)

		return -EINVAL;

	if (!(file->f_mode & FMODE_WRITE))

		return -EBADF;

	if (!(file->f_mode & FMODE_CAN_WRITE))

		return -EINVAL;



	tot_len = iov_iter_count(iter);

	if (!tot_len)

		return 0;

	ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len);

	if (ret < 0)

		return ret;



	ret = call_write_iter(file, iocb, iter);

	if (ret > 0)

		fsnotify_modify(file);



	return ret;

}

EXPORT_SYMBOL(vfs_iocb_iter_write);



ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,

		rwf_t flags)

{

include/linux/fs.h

+16 −0
Original line number Diff line number Diff line
@@ -2078,6 +2078,18 @@ static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) 
	};

}



static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,

			       struct file *filp)

{

	*kiocb = (struct kiocb) {

		.ki_filp = filp,

		.ki_flags = kiocb_src->ki_flags,

		.ki_hint = kiocb_src->ki_hint,

		.ki_ioprio = kiocb_src->ki_ioprio,

		.ki_pos = kiocb_src->ki_pos,

	};

}



/*

 * Inode state bits.  Protected by inode->i_lock

 *
@@ -3108,6 +3120,10 @@ ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, 
		rwf_t flags);

ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,

		rwf_t flags);

ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,

			   struct iov_iter *iter);

ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,

			    struct iov_iter *iter);



/* fs/block_dev.c */

extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);