Merge tag 'configfs-5.13' of git://git.infradead.org/users/hch/configfs

#include <linux/mutex.h>

#include <linux/vmalloc.h>

#include <linux/uaccess.h>

#include <linux/uio.h>

#include <linux/configfs.h>

#include "configfs_internal.h"

	return 0;

}

/**

 *	configfs_read_file - read an attribute.

 *	@file:	file pointer.

 *	@buf:	buffer to fill.

 *	@count:	number of bytes to read.

 *	@ppos:	starting offset in file.

 *

 *	Userspace wants to read an attribute file. The attribute descriptor

 *	is in the file's ->d_fsdata. The target item is in the directory's

 *	->d_fsdata.

 *

 *	We call fill_read_buffer() to allocate and fill the buffer from the

 *	item's show() method exactly once (if the read is happening from

 *	the beginning of the file). That should fill the entire buffer with

 *	all the data the item has to offer for that attribute.

 *	We then call flush_read_buffer() to copy the buffer to userspace

 *	in the increments specified.

 */

static ssize_t

configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)

static ssize_t configfs_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	struct file *file = iocb->ki_filp;

	struct configfs_buffer *buffer = file->private_data;

	ssize_t retval = 0;

		if (retval)

			goto out;

	}

	pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",

		 __func__, count, *ppos, buffer->page);

	retval = simple_read_from_buffer(buf, count, ppos, buffer->page,

					 buffer->count);

	pr_debug("%s: count = %zd, pos = %lld, buf = %s\n",

		 __func__, iov_iter_count(to), iocb->ki_pos, buffer->page);

	retval = copy_to_iter(buffer->page, buffer->count, to);

	iocb->ki_pos += retval;

	if (retval == 0)

		retval = -EFAULT;

out:

	mutex_unlock(&buffer->mutex);

	return retval;

}

/**

 *	configfs_read_bin_file - read a binary attribute.

 *	@file:	file pointer.

 *	@buf:	buffer to fill.

 *	@count:	number of bytes to read.

 *	@ppos:	starting offset in file.

 *

 *	Userspace wants to read a binary attribute file. The attribute

 *	descriptor is in the file's ->d_fsdata. The target item is in the

 *	directory's ->d_fsdata.

 *

 *	We check whether we need to refill the buffer. If so we will

 *	call the attributes' attr->read() twice. The first time we

 *	will pass a NULL as a buffer pointer, which the attributes' method

 *	will use to return the size of the buffer required. If no error

 *	occurs we will allocate the buffer using vmalloc and call

 *	attr->read() again passing that buffer as an argument.

 *	Then we just copy to user-space using simple_read_from_buffer.

 */

static ssize_t

configfs_read_bin_file(struct file *file, char __user *buf,

		       size_t count, loff_t *ppos)

static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	struct file *file = iocb->ki_filp;

	struct configfs_fragment *frag = to_frag(file);

	struct configfs_buffer *buffer = file->private_data;

	ssize_t retval = 0;

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

	ssize_t len;

	mutex_lock(&buffer->mutex);

		buffer->needs_read_fill = 0;

	}

	retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer,

					buffer->bin_buffer_size);

	retval = copy_to_iter(buffer->bin_buffer, buffer->bin_buffer_size, to);

	iocb->ki_pos += retval;

	if (retval == 0)

		retval = -EFAULT;

out:

	mutex_unlock(&buffer->mutex);

	return retval;

}

/**

 *	fill_write_buffer - copy buffer from userspace.

 *	@buffer:	data buffer for file.

 *	@buf:		data from user.

 *	@count:		number of bytes in @userbuf.

 *

 *	Allocate @buffer->page if it hasn't been already, then

 *	copy the user-supplied buffer into it.

 */

static int

fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size_t count)

static int fill_write_buffer(struct configfs_buffer *buffer,

			     struct iov_iter *from)

{

	int error;

	int copied;

	if (!buffer->page)

		buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);

	if (!buffer->page)

		return -ENOMEM;

	if (count >= SIMPLE_ATTR_SIZE)

		count = SIMPLE_ATTR_SIZE - 1;

	error = copy_from_user(buffer->page,buf,count);

	copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);

	buffer->needs_read_fill = 1;

	/* if buf is assumed to contain a string, terminate it by \0,

	 * so e.g. sscanf() can scan the string easily */

	buffer->page[count] = 0;

	return error ? -EFAULT : count;

	buffer->page[copied] = 0;

	return copied ? : -EFAULT;

}

static int

}

/**

 *	configfs_write_file - write an attribute.

 *	@file:	file pointer

 *	@buf:	data to write

 *	@count:	number of bytes

 *	@ppos:	starting offset

 *

 *	Similar to configfs_read_file(), though working in the opposite direction.

 *	We allocate and fill the data from the user in fill_write_buffer(),

 *	then push it to the config_item in flush_write_buffer().

/*

 * There is no easy way for us to know if userspace is only doing a partial

 *	write, so we don't support them. We expect the entire buffer to come

 *	on the first write.

 *	Hint: if you're writing a value, first read the file, modify only

 *	the value you're changing, then write entire buffer back.

 * write, so we don't support them. We expect the entire buffer to come on the

 * first write.

 * Hint: if you're writing a value, first read the file, modify only the value

 * you're changing, then write entire buffer back.

 */

static ssize_t

configfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos)

static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from)

{

	struct file *file = iocb->ki_filp;

	struct configfs_buffer *buffer = file->private_data;

	ssize_t len;

	mutex_lock(&buffer->mutex);

	len = fill_write_buffer(buffer, buf, count);

	len = fill_write_buffer(buffer, from);

	if (len > 0)

		len = flush_write_buffer(file, buffer, len);

	if (len > 0)

		*ppos += len;

		iocb->ki_pos += len;

	mutex_unlock(&buffer->mutex);

	return len;

}

/**

 *	configfs_write_bin_file - write a binary attribute.

 *	@file:	file pointer

 *	@buf:	data to write

 *	@count:	number of bytes

 *	@ppos:	starting offset

 *

 *	Writing to a binary attribute file is similar to a normal read.

 *	We buffer the consecutive writes (binary attribute files do not

 *	support lseek) in a continuously growing buffer, but we don't

 *	commit until the close of the file.

 */

static ssize_t

configfs_write_bin_file(struct file *file, const char __user *buf,

			size_t count, loff_t *ppos)

static ssize_t configfs_bin_write_iter(struct kiocb *iocb,

				       struct iov_iter *from)

{

	struct file *file = iocb->ki_filp;

	struct configfs_buffer *buffer = file->private_data;

	void *tbuf = NULL;

	size_t end_offset;

	ssize_t len;

	mutex_lock(&buffer->mutex);

	buffer->write_in_progress = true;

	/* buffer grows? */

	if (*ppos + count > buffer->bin_buffer_size) {

		if (buffer->cb_max_size &&

			*ppos + count > buffer->cb_max_size) {

	end_offset = iocb->ki_pos + iov_iter_count(from);

	if (end_offset > buffer->bin_buffer_size) {

		if (buffer->cb_max_size && end_offset > buffer->cb_max_size) {

			len = -EFBIG;

			goto out;

		}

		tbuf = vmalloc(*ppos + count);

		tbuf = vmalloc(end_offset);

		if (tbuf == NULL) {

			len = -ENOMEM;

			goto out;

		/* clear the new area */

		memset(tbuf + buffer->bin_buffer_size, 0,

			*ppos + count - buffer->bin_buffer_size);

			end_offset - buffer->bin_buffer_size);

		buffer->bin_buffer = tbuf;

		buffer->bin_buffer_size = *ppos + count;

		buffer->bin_buffer_size = end_offset;

	}

	len = simple_write_to_buffer(buffer->bin_buffer,

			buffer->bin_buffer_size, ppos, buf, count);

	len = copy_from_iter(buffer->bin_buffer, buffer->bin_buffer_size, from);

out:

	mutex_unlock(&buffer->mutex);

	return len;

	return len ? : -EFAULT;

}

static int __configfs_open_file(struct inode *inode, struct file *file, int type)

{

	struct configfs_buffer *buffer = file->private_data;

	buffer->read_in_progress = false;

	if (buffer->write_in_progress) {

		struct configfs_fragment *frag = to_frag(file);

		buffer->write_in_progress = false;

		down_read(&frag->frag_sem);

		if (!frag->frag_dead) {

					buffer->bin_buffer_size);

		}

		up_read(&frag->frag_sem);

		/* vfree on NULL is safe */

		vfree(buffer->bin_buffer);

		buffer->bin_buffer = NULL;

		buffer->bin_buffer_size = 0;

		buffer->needs_read_fill = 1;

	}

	vfree(buffer->bin_buffer);

	configfs_release(inode, file);

	return 0;

}

const struct file_operations configfs_file_operations = {

	.read		= configfs_read_file,

	.write		= configfs_write_file,

	.read_iter	= configfs_read_iter,

	.write_iter	= configfs_write_iter,

	.llseek		= generic_file_llseek,

	.open		= configfs_open_file,

	.release	= configfs_release,

};

const struct file_operations configfs_bin_file_operations = {

	.read		= configfs_read_bin_file,

	.write		= configfs_write_bin_file,

	.read_iter	= configfs_bin_read_iter,

	.write_iter	= configfs_bin_write_iter,

	.llseek		= NULL,		/* bin file is not seekable */

	.open		= configfs_open_bin_file,

	.release	= configfs_release_bin_file,

/**

 *	configfs_create_bin_file - create a binary attribute file for an item.

 *	@item:	item we're creating for.

 *	@attr:	atrribute descriptor.

 *	@bin_attr: atrribute descriptor.

 */

int configfs_create_bin_file(struct config_item *item,