netns xfrm: fix "ip xfrm state|policy count" misreport

[safe/jmp/linux-2.6] / Documentation / filesystems / sysfs.txt

diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 7f27b8f..931c806 100644 (file)
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -2,8 +2,10 @@
 sysfs - _The_ filesystem for exporting kernel objects. 
 
 Patrick Mochel <mochel@osdl.org>
+Mike Murphy <mamurph@cs.clemson.edu>
 
-10 January 2003
+Revised:    22 February 2009
+Original:   10 January 2003
 
 
 What it is:
@@ -21,7 +23,8 @@ interface.
 Using sysfs
 ~~~~~~~~~~~
 
-sysfs is always compiled in. You can access it by doing:
+sysfs is always compiled in if CONFIG_SYSFS is defined. You can access
+it by doing:
 
     mount -t sysfs sysfs /sys 
 
@@ -64,12 +67,13 @@ An attribute definition is simply:
 
 struct attribute {
         char                    * name;
+        struct module          *owner;
         mode_t                  mode;
 };
 
 
-int sysfs_create_file(struct kobject * kobj, struct attribute * attr);
-void sysfs_remove_file(struct kobject * kobj, struct attribute * attr);
+int sysfs_create_file(struct kobject * kobj, const struct attribute * attr);
+void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr);
 
 
 A bare attribute contains no means to read or write the value of the
@@ -80,22 +84,20 @@ a specific object type.
 For example, the driver model defines struct device_attribute like:
 
 struct device_attribute {
-        struct attribute        attr;
-        ssize_t (*show)(struct device * dev, char * buf);
-        ssize_t (*store)(struct device * dev, const char * buf);
+       struct attribute        attr;
+       ssize_t (*show)(struct device *dev, struct device_attribute *attr,
+                       char *buf);
+       ssize_t (*store)(struct device *dev, struct device_attribute *attr,
+                        const char *buf, size_t count);
 };
 
-int device_create_file(struct device *, struct device_attribute *);
-void device_remove_file(struct device *, struct device_attribute *);
+int device_create_file(struct device *, const struct device_attribute *);
+void device_remove_file(struct device *, const struct device_attribute *);
 
 It also defines this helper for defining device attributes: 
 
-#define DEVICE_ATTR(_name, _mode, _show, _store)      \
-struct device_attribute dev_attr_##_name = {            \
-        .attr = {.name  = __stringify(_name) , .mode   = _mode },      \
-        .show   = _show,                                \
-        .store  = _store,                               \
-};
+#define DEVICE_ATTR(_name, _mode, _show, _store) \
+struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store)
 
 For example, declaring
 
@@ -107,9 +109,9 @@ static struct device_attribute dev_attr_foo = {
        .attr   = {
                .name = "foo",
                .mode = S_IWUSR | S_IRUGO,
+               .show = show_foo,
+               .store = store_foo,
        },
-       .show = show_foo,
-       .store = store_foo,
 };
 
 
@@ -161,10 +163,12 @@ To read or write attributes, show() or store() methods must be
 specified when declaring the attribute. The method types should be as
 simple as those defined for device attributes:
 
-        ssize_t (*show)(struct device * dev, char * buf);
-        ssize_t (*store)(struct device * dev, const char * buf);
+ssize_t (*show)(struct device * dev, struct device_attribute * attr,
+                char * buf);
+ssize_t (*store)(struct device * dev, struct device_attribute * attr,
+                 const char * buf);
 
-IOW, they should take only an object and a buffer as parameters. 
+IOW, they should take only an object, an attribute, and a buffer as parameters.
 
 
 sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the
@@ -248,6 +252,7 @@ The top level sysfs directory looks like:
 block/
 bus/
 class/
+dev/
 devices/
 firmware/
 net/
@@ -274,6 +279,11 @@ fs/ contains a directory for some filesystems.  Currently each
 filesystem wanting to export attributes must create its own hierarchy
 below fs/ (see ./fuse.txt for an example).
 
+dev/ contains two directories char/ and block/. Inside these two
+directories there are symlinks named <major>:<minor>.  These symlinks
+point to the sysfs directory for the given device.  /sys/dev provides a
+quick way to lookup the sysfs interface for a device from the result of
+a stat(2) operation.
 
 More information can driver-model specific features can be found in
 Documentation/driver-model/. 
@@ -293,19 +303,21 @@ The following interface layers currently exist in sysfs:
 Structure:
 
 struct device_attribute {
-        struct attribute        attr;
-        ssize_t (*show)(struct device * dev, char * buf);
-        ssize_t (*store)(struct device * dev, const char * buf);
+       struct attribute        attr;
+       ssize_t (*show)(struct device *dev, struct device_attribute *attr,
+                       char *buf);
+       ssize_t (*store)(struct device *dev, struct device_attribute *attr,
+                        const char *buf, size_t count);
 };
 
 Declaring:
 
-DEVICE_ATTR(_name, _str, _mode, _show, _store);
+DEVICE_ATTR(_name, _mode, _show, _store);
 
 Creation/Removal:
 
-int device_create_file(struct device *device, struct device_attribute * attr);
-void device_remove_file(struct device * dev, struct device_attribute * attr);
+int device_create_file(struct device *dev, const struct device_attribute * attr);
+void device_remove_file(struct device *dev, const struct device_attribute * attr);
 
 
 - bus drivers (include/linux/device.h)
@@ -336,7 +348,8 @@ Structure:
 struct driver_attribute {
         struct attribute        attr;
         ssize_t (*show)(struct device_driver *, char * buf);
-        ssize_t (*store)(struct device_driver *, const char * buf);
+        ssize_t (*store)(struct device_driver *, const char * buf,
+                         size_t count);
 };
 
 Declaring:
@@ -345,7 +358,7 @@ DRIVER_ATTR(_name, _mode, _show, _store)
 
 Creation/Removal:
 
-int driver_create_file(struct device_driver *, struct driver_attribute *);
-void driver_remove_file(struct device_driver *, struct driver_attribute *);
+int driver_create_file(struct device_driver *, const struct driver_attribute *);
+void driver_remove_file(struct device_driver *, const struct driver_attribute *);