Commit cc099e0b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Greg Kroah-Hartman
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kernfs: implement ->write_iter 



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

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210120204631.274206-3-hch@lst.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4eaad21a

fs/kernfs/file.c

+10 −18
Original line number Diff line number Diff line
@@ -242,13 +242,7 @@ static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
	return kernfs_file_read_iter(iocb, iter);

}



/**

 * kernfs_fop_write - kernfs vfs write callback

 * @file: file pointer

 * @user_buf: data to write

 * @count: number of bytes

 * @ppos: starting offset

 *

/*

 * Copy data in from userland and pass it to the matching kernfs write

 * operation.

 *
@@ -258,20 +252,18 @@ static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
 * modify only the the value you're changing, then write entire buffer

 * back.

 */

static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,

				size_t count, loff_t *ppos)

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

{

	struct kernfs_open_file *of = kernfs_of(file);

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

	ssize_t len = iov_iter_count(iter);

	const struct kernfs_ops *ops;

	ssize_t len;

	char *buf;



	if (of->atomic_write_len) {

		len = count;

		if (len > of->atomic_write_len)

			return -E2BIG;

	} else {

		len = min_t(size_t, count, PAGE_SIZE);

		len = min_t(size_t, len, PAGE_SIZE);

	}



	buf = of->prealloc_buf;
@@ -282,7 +274,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, 
	if (!buf)

		return -ENOMEM;



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

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

		len = -EFAULT;

		goto out_free;

	}
@@ -301,7 +293,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, 


	ops = kernfs_ops(of->kn);

	if (ops->write)

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

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

	else

		len = -EINVAL;
@@ -309,7 +301,7 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, 
	mutex_unlock(&of->mutex);



	if (len > 0)

		*ppos += len;

		iocb->ki_pos += len;



out_free:

	if (buf == of->prealloc_buf)
@@ -662,7 +654,7 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) 


	/*

	 * Write path needs to atomic_write_len outside active reference.

	 * Cache it in open_file.  See kernfs_fop_write() for details.

	 * Cache it in open_file.  See kernfs_fop_write_iter() for details.

	 */

	of->atomic_write_len = ops->atomic_write_len;
@@ -950,7 +942,7 @@ EXPORT_SYMBOL_GPL(kernfs_notify); 


const struct file_operations kernfs_file_fops = {

	.read_iter	= kernfs_fop_read_iter,

	.write		= kernfs_fop_write,

	.write_iter	= kernfs_fop_write_iter,

	.llseek		= generic_file_llseek,

	.mmap		= kernfs_fop_mmap,

	.open		= kernfs_fop_open,