Commit 51798222 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Nicholas Bellinger

configfs: remove old API

Remove the old show_attribute and store_attribute methods and update
the documentation.  Also replace the two C samples with a single new
one in the proper samples directory where people expect to find it.
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 45b99773
subdir-y := configfs
# List of programs to build
hostprogs-y := dnotify_test
......
ifneq ($(CONFIG_CONFIGFS_FS),)
obj-m += configfs_example_explicit.o configfs_example_macros.o
endif
......@@ -160,12 +160,6 @@ among other things. For that, it needs a type.
struct configfs_item_operations {
void (*release)(struct config_item *);
ssize_t (*show_attribute)(struct config_item *,
struct configfs_attribute *,
char *);
ssize_t (*store_attribute)(struct config_item *,
struct configfs_attribute *,
const char *, size_t);
int (*allow_link)(struct config_item *src,
struct config_item *target);
int (*drop_link)(struct config_item *src,
......@@ -183,9 +177,7 @@ The most basic function of a config_item_type is to define what
operations can be performed on a config_item. All items that have been
allocated dynamically will need to provide the ct_item_ops->release()
method. This method is called when the config_item's reference count
reaches zero. Items that wish to display an attribute need to provide
the ct_item_ops->show_attribute() method. Similarly, storing a new
attribute value uses the store_attribute() method.
reaches zero.
[struct configfs_attribute]
......@@ -193,6 +185,8 @@ attribute value uses the store_attribute() method.
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);
};
When a config_item wants an attribute to appear as a file in the item's
......@@ -202,10 +196,10 @@ config_item_type->ct_attrs. When the item appears in configfs, the
attribute file will appear with the configfs_attribute->ca_name
filename. configfs_attribute->ca_mode specifies the file permissions.
If an attribute is readable and the config_item provides a
ct_item_ops->show_attribute() method, that method will be called
whenever userspace asks for a read(2) on the attribute. The converse
will happen for write(2).
If an attribute is readable and provides a ->show method, that method will
be called whenever userspace asks for a read(2) on the attribute. If an
attribute is writable and provides a ->store method, that method will be
be called whenever userspace asks for a write(2) on the attribute.
[struct config_group]
......@@ -311,20 +305,10 @@ the subsystem must be ready for it.
[An Example]
The best example of these basic concepts is the simple_children
subsystem/group and the simple_child item in configfs_example_explicit.c
and configfs_example_macros.c. It shows a trivial object displaying and
storing an attribute, and a simple group creating and destroying these
children.
The only difference between configfs_example_explicit.c and
configfs_example_macros.c is how the attributes of the childless item
are defined. The childless item has extended attributes, each with
their own show()/store() operation. This follows a convention commonly
used in sysfs. configfs_example_explicit.c creates these attributes
by explicitly defining the structures involved. Conversely
configfs_example_macros.c uses some convenience macros from configfs.h
to define the attributes. These macros are similar to their sysfs
counterparts.
subsystem/group and the simple_child item in
samples/configfs/configfs_sample.c. It shows a trivial object displaying
and storing an attribute, and a simple group creating and destroying
these children.
[Hierarchy Navigation and the Subsystem Mutex]
......
......@@ -65,7 +65,6 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
{
struct configfs_attribute * attr = to_attr(dentry);
struct config_item * item = to_item(dentry->d_parent);
struct configfs_item_operations * ops = buffer->ops;
int ret = 0;
ssize_t count;
......@@ -74,10 +73,7 @@ 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);
count = attr->show(item, buffer->page);
buffer->needs_read_fill = 0;
BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
......@@ -175,10 +171,7 @@ flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size
{
struct configfs_attribute * attr = to_attr(dentry);
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);
}
......@@ -243,8 +236,7 @@ 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 && !attr->store))
if (!(inode->i_mode & S_IWUGO) || !attr->store)
goto Eaccess;
}
......@@ -254,8 +246,7 @@ 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 && !attr->show))
if (!(inode->i_mode & S_IRUGO) || !attr->show)
goto Eaccess;
}
......
......@@ -154,86 +154,6 @@ static struct configfs_attribute _pfx##attr_##_name = { \
.store = _pfx##_name##_store, \
}
/*
* Users often need to create attribute structures for their configurable
* attributes, containing a configfs_attribute member and function pointers
* for the show() and store() operations on that attribute. If they don't
* need anything else on the extended attribute structure, they can use
* this macro to define it The argument _item is the name of the
* config_item structure.
*/
#define CONFIGFS_ATTR_STRUCT(_item) \
struct _item##_attribute { \
struct configfs_attribute attr; \
ssize_t (*show)(struct _item *, char *); \
ssize_t (*store)(struct _item *, const char *, size_t); \
}
/*
* With the extended attribute structure, users can use this macro
* (similar to sysfs' __ATTR) to make defining attributes easier.
* An example:
* #define MYITEM_ATTR(_name, _mode, _show, _store) \
* struct myitem_attribute childless_attr_##_name = \
* __CONFIGFS_ATTR(_name, _mode, _show, _store)
*/
#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
{ \
.attr = { \
.ca_name = __stringify(_name), \
.ca_mode = _mode, \
.ca_owner = THIS_MODULE, \
}, \
.show = _show, \
.store = _store, \
}
/* Here is a readonly version, only requiring a show() operation */
#define __CONFIGFS_ATTR_RO(_name, _show) \
{ \
.attr = { \
.ca_name = __stringify(_name), \
.ca_mode = 0444, \
.ca_owner = THIS_MODULE, \
}, \
.show = _show, \
}
/*
* With these extended attributes, the simple show_attribute() and
* store_attribute() operations need to call the show() and store() of the
* attributes. This is a common pattern, so we provide a macro to define
* them. The argument _item is the name of the config_item structure.
* This macro expects the attributes to be named "struct <name>_attribute"
* and the function to_<name>() to exist;
*/
#define CONFIGFS_ATTR_OPS(_item) \
static ssize_t _item##_attr_show(struct config_item *item, \
struct configfs_attribute *attr, \
char *page) \
{ \
struct _item *_item = to_##_item(item); \
struct _item##_attribute *_item##_attr = \
container_of(attr, struct _item##_attribute, attr); \
ssize_t ret = 0; \
\
if (_item##_attr->show) \
ret = _item##_attr->show(_item, page); \
return ret; \
} \
static ssize_t _item##_attr_store(struct config_item *item, \
struct configfs_attribute *attr, \
const char *page, size_t count) \
{ \
struct _item *_item = to_##_item(item); \
struct _item##_attribute *_item##_attr = \
container_of(attr, struct _item##_attribute, attr); \
ssize_t ret = -EINVAL; \
\
if (_item##_attr->store) \
ret = _item##_attr->store(_item, page, count); \
return ret; \
}
/*
* If allow_link() exists, the item can symlink(2) out to other
* items. If the item is a group, it may support mkdir(2).
......@@ -250,8 +170,6 @@ static ssize_t _item##_attr_store(struct config_item *item, \
*/
struct configfs_item_operations {
void (*release)(struct config_item *);
ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
int (*allow_link)(struct config_item *src, struct config_item *target);
int (*drop_link)(struct config_item *src, struct config_item *target);
};
......
......@@ -70,4 +70,10 @@ config SAMPLE_LIVEPATCH
Builds a sample live patch that replaces the procfs handler
for /proc/cmdline to print "this has been live patched".
config SAMPLE_CONFIGFS
tristate "Build configfs patching sample -- loadable modules only"
depends on CONFIGFS_FS && m
help
Builds a sample configfs interface.
endif # SAMPLES
# Makefile for Linux samples code
obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ livepatch/ \
hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/
hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ \
configfs/
obj-$(CONFIG_SAMPLE_CONFIGFS) += configfs_sample.o
......@@ -54,18 +54,13 @@ struct childless {
static inline struct childless *to_childless(struct config_item *item)
{
return item ? container_of(to_configfs_subsystem(to_config_group(item)), struct childless, subsys) : NULL;
return item ? container_of(to_configfs_subsystem(to_config_group(item)),
struct childless, subsys) : NULL;
}
CONFIGFS_ATTR_STRUCT(childless);
#define CHILDLESS_ATTR(_name, _mode, _show, _store) \
struct childless_attribute childless_attr_##_name = __CONFIGFS_ATTR(_name, _mode, _show, _store)
#define CHILDLESS_ATTR_RO(_name, _show) \
struct childless_attribute childless_attr_##_name = __CONFIGFS_ATTR_RO(_name, _show);
static ssize_t childless_showme_read(struct childless *childless,
char *page)
static ssize_t childless_showme_show(struct config_item *item, char *page)
{
struct childless *childless = to_childless(item);
ssize_t pos;
pos = sprintf(page, "%d\n", childless->showme);
......@@ -74,16 +69,15 @@ static ssize_t childless_showme_read(struct childless *childless,
return pos;
}
static ssize_t childless_storeme_read(struct childless *childless,
char *page)
static ssize_t childless_storeme_show(struct config_item *item, char *page)
{
return sprintf(page, "%d\n", childless->storeme);
return sprintf(page, "%d\n", to_childless(item)->storeme);
}
static ssize_t childless_storeme_write(struct childless *childless,
const char *page,
size_t count)
static ssize_t childless_storeme_store(struct config_item *item,
const char *page, size_t count)
{
struct childless *childless = to_childless(item);
unsigned long tmp;
char *p = (char *) page;
......@@ -99,8 +93,7 @@ static ssize_t childless_storeme_write(struct childless *childless,
return count;
}
static ssize_t childless_description_read(struct childless *childless,
char *page)
static ssize_t childless_description_show(struct config_item *item, char *page)
{
return sprintf(page,
"[01-childless]\n"
......@@ -111,26 +104,18 @@ static ssize_t childless_description_read(struct childless *childless,
"than a directory in /proc.\n");
}
CHILDLESS_ATTR_RO(showme, childless_showme_read);
CHILDLESS_ATTR(storeme, S_IRUGO | S_IWUSR, childless_storeme_read,
childless_storeme_write);
CHILDLESS_ATTR_RO(description, childless_description_read);
CONFIGFS_ATTR_RO(childless_, showme);
CONFIGFS_ATTR(childless_, storeme);
CONFIGFS_ATTR_RO(childless_, description);
static struct configfs_attribute *childless_attrs[] = {
&childless_attr_showme.attr,
&childless_attr_storeme.attr,
&childless_attr_description.attr,
&childless_attr_showme,
&childless_attr_storeme,
&childless_attr_description,
NULL,
};
CONFIGFS_ATTR_OPS(childless);
static struct configfs_item_operations childless_item_ops = {
.show_attribute = childless_attr_show,
.store_attribute = childless_attr_store,
};
static struct config_item_type childless_type = {
.ct_item_ops = &childless_item_ops,
.ct_attrs = childless_attrs,
.ct_owner = THIS_MODULE,
};
......@@ -168,32 +153,13 @@ static inline struct simple_child *to_simple_child(struct config_item *item)
return item ? container_of(item, struct simple_child, item) : NULL;
}
static struct configfs_attribute simple_child_attr_storeme = {
.ca_owner = THIS_MODULE,
.ca_name = "storeme",
.ca_mode = S_IRUGO | S_IWUSR,
};
static struct configfs_attribute *simple_child_attrs[] = {
&simple_child_attr_storeme,
NULL,
};
static ssize_t simple_child_attr_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
static ssize_t simple_child_storeme_show(struct config_item *item, char *page)
{
ssize_t count;
struct simple_child *simple_child = to_simple_child(item);
count = sprintf(page, "%d\n", simple_child->storeme);
return count;
return sprintf(page, "%d\n", to_simple_child(item)->storeme);
}
static ssize_t simple_child_attr_store(struct config_item *item,
struct configfs_attribute *attr,
const char *page, size_t count)
static ssize_t simple_child_storeme_store(struct config_item *item,
const char *page, size_t count)
{
struct simple_child *simple_child = to_simple_child(item);
unsigned long tmp;
......@@ -211,6 +177,13 @@ static ssize_t simple_child_attr_store(struct config_item *item,
return count;
}
CONFIGFS_ATTR(simple_child_, storeme);
static struct configfs_attribute *simple_child_attrs[] = {
&simple_child_attr_storeme,
NULL,
};
static void simple_child_release(struct config_item *item)
{
kfree(to_simple_child(item));
......@@ -218,8 +191,6 @@ static void simple_child_release(struct config_item *item)
static struct configfs_item_operations simple_child_item_ops = {
.release = simple_child_release,
.show_attribute = simple_child_attr_show,
.store_attribute = simple_child_attr_store,
};
static struct config_item_type simple_child_type = {
......@@ -235,10 +206,12 @@ struct simple_children {
static inline struct simple_children *to_simple_children(struct config_item *item)
{
return item ? container_of(to_config_group(item), struct simple_children, group) : NULL;
return item ? container_of(to_config_group(item),
struct simple_children, group) : NULL;
}
static struct config_item *simple_children_make_item(struct config_group *group, const char *name)
static struct config_item *simple_children_make_item(struct config_group *group,
const char *name)
{
struct simple_child *simple_child;
......@@ -254,20 +227,8 @@ static struct config_item *simple_children_make_item(struct config_group *group,
return &simple_child->item;
}
static struct configfs_attribute simple_children_attr_description = {
.ca_owner = THIS_MODULE,
.ca_name = "description",
.ca_mode = S_IRUGO,
};
static struct configfs_attribute *simple_children_attrs[] = {
&simple_children_attr_description,
NULL,
};
static ssize_t simple_children_attr_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
static ssize_t simple_children_description_show(struct config_item *item,
char *page)
{
return sprintf(page,
"[02-simple-children]\n"
......@@ -276,6 +237,13 @@ static ssize_t simple_children_attr_show(struct config_item *item,
"items have only one attribute that is readable and writeable.\n");
}
CONFIGFS_ATTR_RO(simple_children_, description);
static struct configfs_attribute *simple_children_attrs[] = {
&simple_children_attr_description,
NULL,
};
static void simple_children_release(struct config_item *item)
{
kfree(to_simple_children(item));
......@@ -283,7 +251,6 @@ static void simple_children_release(struct config_item *item)
static struct configfs_item_operations simple_children_item_ops = {
.release = simple_children_release,
.show_attribute = simple_children_attr_show,
};
/*
......@@ -323,7 +290,8 @@ static struct configfs_subsystem simple_children_subsys = {
* children of its own.
*/
static struct config_group *group_children_make_group(struct config_group *group, const char *name)
static struct config_group *group_children_make_group(
struct config_group *group, const char *name)
{
struct simple_children *simple_children;
......@@ -338,20 +306,8 @@ static struct config_group *group_children_make_group(struct config_group *group
return &simple_children->group;
}
static struct configfs_attribute group_children_attr_description = {
.ca_owner = THIS_MODULE,
.ca_name = "description",
.ca_mode = S_IRUGO,
};
static struct configfs_attribute *group_children_attrs[] = {
&group_children_attr_description,
NULL,
};
static ssize_t group_children_attr_show(struct config_item *item,
struct configfs_attribute *attr,
char *page)
static ssize_t group_children_description_show(struct config_item *item,
char *page)
{
return sprintf(page,
"[03-group-children]\n"
......@@ -360,8 +316,11 @@ static ssize_t group_children_attr_show(struct config_item *item,
"groups are like the subsystem simple-children.\n");
}
static struct configfs_item_operations group_children_item_ops = {
.show_attribute = group_children_attr_show,
CONFIGFS_ATTR_RO(group_children_, description);
static struct configfs_attribute *group_children_attrs[] = {
&group_children_attr_description,
NULL,
};
/*
......@@ -373,7 +332,6 @@ static struct configfs_group_operations group_children_group_ops = {
};
static struct config_item_type group_children_type = {
.ct_item_ops = &group_children_item_ops,
.ct_group_ops = &group_children_group_ops,
.ct_attrs = group_children_attrs,
.ct_owner = THIS_MODULE,
......
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