Commit 4eaad21a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
Browse files

kernfs: implement ->read_iter 



Switch kernfs to implement the read_iter method instead of plain old
read to prepare to supporting splice and sendfile again.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210120204631.274206-2-hch@lst.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 895bee27

fs/kernfs/file.c

+12 −23
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/pagemap.h>

#include <linux/sched/mm.h>

#include <linux/fsnotify.h>

#include <linux/uio.h>



#include "kernfs-internal.h"
@@ -180,11 +181,10 @@ static const struct seq_operations kernfs_seq_ops = { 
 * it difficult to use seq_file.  Implement simplistic custom buffering for

 * bin files.

 */

static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,

				       char __user *user_buf, size_t count,

				       loff_t *ppos)

static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	ssize_t len = min_t(size_t, count, PAGE_SIZE);

	struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);

	ssize_t len = min_t(size_t, iov_iter_count(iter), PAGE_SIZE);

	const struct kernfs_ops *ops;

	char *buf;
@@ -210,7 +210,7 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, 
	of->event = atomic_read(&of->kn->attr.open->event);

	ops = kernfs_ops(of->kn);

	if (ops->read)

		len = ops->read(of, buf, len, *ppos);

		len = ops->read(of, buf, len, iocb->ki_pos);

	else

		len = -EINVAL;
@@ -220,12 +220,12 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, 
	if (len < 0)

		goto out_free;



	if (copy_to_user(user_buf, buf, len)) {

	if (copy_to_iter(buf, len, iter) != len) {

		len = -EFAULT;

		goto out_free;

	}



	*ppos += len;

	iocb->ki_pos += len;



 out_free:

	if (buf == of->prealloc_buf)
@@ -235,22 +235,11 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, 
	return len;

}



/**

 * kernfs_fop_read - kernfs vfs read callback

 * @file: file pointer

 * @user_buf: data to write

 * @count: number of bytes

 * @ppos: starting offset

 */

static ssize_t kernfs_fop_read(struct file *file, char __user *user_buf,

			       size_t count, loff_t *ppos)

static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	struct kernfs_open_file *of = kernfs_of(file);



	if (of->kn->flags & KERNFS_HAS_SEQ_SHOW)

		return seq_read(file, user_buf, count, ppos);

	else

		return kernfs_file_direct_read(of, user_buf, count, ppos);

	if (kernfs_of(iocb->ki_filp)->kn->flags & KERNFS_HAS_SEQ_SHOW)

		return seq_read_iter(iocb, iter);

	return kernfs_file_read_iter(iocb, iter);

}



/**
@@ -960,7 +949,7 @@ void kernfs_notify(struct kernfs_node *kn) 
EXPORT_SYMBOL_GPL(kernfs_notify);



const struct file_operations kernfs_file_fops = {

	.read		= kernfs_fop_read,

	.read_iter	= kernfs_fop_read_iter,

	.write		= kernfs_fop_write,

	.llseek		= generic_file_llseek,

	.mmap		= kernfs_fop_mmap,