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r: 7210
b: refs/heads/master
c: f8d825b
h: refs/heads/master
v: v3
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Jan Veldeman authored and Greg Kroah-Hartman committed Sep 5, 2005
1 parent b77fe1a commit 31b6726
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2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 9a8af6b3b64ee97a1aeecde017ffd02e6796913a
refs/heads/master: f8d825bfb8d2a7546eeb57569d0eedf8c5565d28
26 changes: 13 additions & 13 deletions trunk/Documentation/filesystems/sysfs.txt
Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,7 @@ void device_remove_file(struct device *, struct device_attribute *);

It also defines this helper for defining device attributes:

#define DEVICE_ATTR(_name,_mode,_show,_store) \
#define DEVICE_ATTR(_name, _mode, _show, _store) \
struct device_attribute dev_attr_##_name = { \
.attr = {.name = __stringify(_name) , .mode = _mode }, \
.show = _show, \
Expand All @@ -99,7 +99,7 @@ struct device_attribute dev_attr_##_name = { \

For example, declaring

static DEVICE_ATTR(foo,0644,show_foo,store_foo);
static DEVICE_ATTR(foo, 0644, show_foo, store_foo);

is equivalent to doing:

Expand All @@ -121,8 +121,8 @@ set of sysfs operations for forwarding read and write calls to the
show and store methods of the attribute owners.

struct sysfs_ops {
ssize_t (*show)(struct kobject *, struct attribute *,char *);
ssize_t (*store)(struct kobject *,struct attribute *,const char *);
ssize_t (*show)(struct kobject *, struct attribute *, char *);
ssize_t (*store)(struct kobject *, struct attribute *, const char *);
};

[ Subsystems should have already defined a struct kobj_type as a
Expand All @@ -137,7 +137,7 @@ calls the associated methods.

To illustrate:

#define to_dev_attr(_attr) container_of(_attr,struct device_attribute,attr)
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
#define to_dev(d) container_of(d, struct device, kobj)

static ssize_t
Expand All @@ -148,7 +148,7 @@ dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
ssize_t ret = 0;

if (dev_attr->show)
ret = dev_attr->show(dev,buf);
ret = dev_attr->show(dev, buf);
return ret;
}

Expand Down Expand Up @@ -216,16 +216,16 @@ A very simple (and naive) implementation of a device attribute is:

static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf)
{
return sprintf(buf,"%s\n",dev->name);
return snprintf(buf, PAGE_SIZE, "%s\n", dev->name);
}

static ssize_t store_name(struct device * dev, const char * buf)
{
sscanf(buf,"%20s",dev->name);
return strlen(buf);
sscanf(buf, "%20s", dev->name);
return strnlen(buf, PAGE_SIZE);
}

static DEVICE_ATTR(name,S_IRUGO,show_name,store_name);
static DEVICE_ATTR(name, S_IRUGO, show_name, store_name);


(Note that the real implementation doesn't allow userspace to set the
Expand Down Expand Up @@ -290,7 +290,7 @@ struct device_attribute {

Declaring:

DEVICE_ATTR(_name,_str,_mode,_show,_store);
DEVICE_ATTR(_name, _str, _mode, _show, _store);

Creation/Removal:

Expand All @@ -310,7 +310,7 @@ struct bus_attribute {

Declaring:

BUS_ATTR(_name,_mode,_show,_store)
BUS_ATTR(_name, _mode, _show, _store)

Creation/Removal:

Expand All @@ -331,7 +331,7 @@ struct driver_attribute {

Declaring:

DRIVER_ATTR(_name,_mode,_show,_store)
DRIVER_ATTR(_name, _mode, _show, _store)

Creation/Removal:

Expand Down

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