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Commit 870823e6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Nicholas Bellinger
Browse files

configfs: add show and store methods to struct configfs_attribute 



Add methods to struct configfs_attribute to directly show and store
attributes without adding boilerplate code to every user.  In addition
to the methods this also adds 3 helper macros to define read/write,
read-only and write-only attributes with a single line of code.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 6ff33f39

fs/configfs/file.c

+12 −5
Original line number Diff line number Diff line
@@ -74,7 +74,11 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf 
	if (!buffer->page)

		return -ENOMEM;



	if (ops->show_attribute)

		count = ops->show_attribute(item, attr, buffer->page);

	else

		count = attr->show(item, buffer->page);



	buffer->needs_read_fill = 0;

	BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);

	if (count >= 0)
@@ -173,7 +177,9 @@ flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size 
	struct config_item * item = to_item(dentry->d_parent);

	struct configfs_item_operations * ops = buffer->ops;



	if (ops->store_attribute)

		return ops->store_attribute(item, attr, buffer->page, count);

	return attr->store(item, buffer->page, count);

}
@@ -237,8 +243,8 @@ static int check_perm(struct inode * inode, struct file * file) 
	 * and we must have a store method.

	 */

	if (file->f_mode & FMODE_WRITE) {



		if (!(inode->i_mode & S_IWUGO) || !ops->store_attribute)

		if (!(inode->i_mode & S_IWUGO) ||

		    (!ops->store_attribute && !attr->store))

			goto Eaccess;



	}
@@ -248,7 +254,8 @@ static int check_perm(struct inode * inode, struct file * file) 
	 * must be a show method for it.

	 */

	if (file->f_mode & FMODE_READ) {

		if (!(inode->i_mode & S_IRUGO) || !ops->show_attribute)

		if (!(inode->i_mode & S_IRUGO) ||

		    (!ops->show_attribute && !attr->show))

			goto Eaccess;

	}

include/linux/configfs.h

+27 −0
Original line number Diff line number Diff line
@@ -125,8 +125,35 @@ struct configfs_attribute { 
	const char		*ca_name;

	struct module 		*ca_owner;

	umode_t			ca_mode;

	ssize_t (*show)(struct config_item *, char *);

	ssize_t (*store)(struct config_item *, const char *, size_t);

};



#define CONFIGFS_ATTR(_pfx, _name)			\

static struct configfs_attribute _pfx##attr_##_name = {	\

	.ca_name	= __stringify(_name),		\

	.ca_mode	= S_IRUGO | S_IWUSR,		\

	.ca_owner	= THIS_MODULE,			\

	.show		= _pfx##_name##_show,		\

	.store		= _pfx##_name##_store,		\

}



#define CONFIGFS_ATTR_RO(_pfx, _name)			\

static struct configfs_attribute _pfx##attr_##_name = {	\

	.ca_name	= __stringify(_name),		\

	.ca_mode	= S_IRUGO,			\

	.ca_owner	= THIS_MODULE,			\

	.show		= _pfx##_name##_show,		\

}



#define CONFIGFS_ATTR_WO(_pfx, _name)			\

static struct configfs_attribute _pfx##attr_##_name = {	\

	.ca_name	= __stringify(_name),		\

	.ca_mode	= S_IWUSR,			\

	.ca_owner	= THIS_MODULE,			\

	.store		= _pfx##_name##_store,		\

}



/*

 * Users often need to create attribute structures for their configurable

 * attributes, containing a configfs_attribute member and function pointers