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Commit 2eb645e7 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6:
  driver core: numa: fix BUILD_BUG_ON for node_read_distance
  driver-core: document ERR_PTR() return values
  kobject: documentation: Update to refer to kset-example.c.
  sysdev: the cpu probe/release attributes should be sysdev_class_attributes
  kobject: documentation: Fix erroneous example in kobject doc.
  driver-core: fix missing kernel-doc in firmware_class
  Driver core: Early platform kernel-doc update
  sysfs: fix sysfs lockdep warning in mlx4 code
  sysfs: fix sysfs lockdep warning in infiniband code
  sysfs: fix sysfs lockdep warning in ipmi code
  sysfs: Initialised pci bus legacy_mem field before use
  sysfs: use sysfs_bin_attr_init in firmware class driver
parents 8fdb7e9f 12ee3c0a

Documentation/kobject.txt

+40 −20
Original line number Diff line number Diff line
@@ -59,18 +59,20 @@ nice to have in other objects. The C language does not allow for the 
direct expression of inheritance, so other techniques - such as structure

embedding - must be used.



So, for example, the UIO code has a structure that defines the memory

region associated with a uio device:

(As an aside, for those familiar with the kernel linked list implementation,

this is analogous as to how "list_head" structs are rarely useful on

their own, but are invariably found embedded in the larger objects of

interest.)



struct uio_mem {

So, for example, the UIO code in drivers/uio/uio.c has a structure that

defines the memory region associated with a uio device:



    struct uio_map {

	struct kobject kobj;

	unsigned long addr;

	unsigned long size;

	int memtype;

	void __iomem *internal_addr;

	struct uio_mem *mem;

    };



If you have a struct uio_mem structure, finding its embedded kobject is

If you have a struct uio_map structure, finding its embedded kobject is

just a matter of using the kobj member.  Code that works with kobjects will

often have the opposite problem, however: given a struct kobject pointer,

what is the pointer to the containing structure?  You must avoid tricks
@@ -79,17 +81,34 @@ and, instead, use the container_of() macro, found in <linux/kernel.h>: 


    container_of(pointer, type, member)



where pointer is the pointer to the embedded kobject, type is the type of

the containing structure, and member is the name of the structure field to

which pointer points.  The return value from container_of() is a pointer to

the given type. So, for example, a pointer "kp" to a struct kobject

embedded within a struct uio_mem could be converted to a pointer to the

containing uio_mem structure with:

where:



  * "pointer" is the pointer to the embedded kobject,

  * "type" is the type of the containing structure, and

  * "member" is the name of the structure field to which "pointer" points.



The return value from container_of() is a pointer to the corresponding

container type. So, for example, a pointer "kp" to a struct kobject

embedded *within* a struct uio_map could be converted to a pointer to the

*containing* uio_map structure with:



    struct uio_map *u_map = container_of(kp, struct uio_map, kobj);



For convenience, programmers often define a simple macro for "back-casting"

kobject pointers to the containing type.  Exactly this happens in the

earlier drivers/uio/uio.c, as you can see here:



    struct uio_map {

        struct kobject kobj;

        struct uio_mem *mem;

    };



    #define to_map(map) container_of(map, struct uio_map, kobj)



    struct uio_mem *u_mem = container_of(kp, struct uio_mem, kobj);

where the macro argument "map" is a pointer to the struct kobject in

question.  That macro is subsequently invoked with:



Programmers often define a simple macro for "back-casting" kobject pointers

to the containing type.

    struct uio_map *map = to_map(kobj);





Initialization of kobjects
@@ -387,4 +406,5 @@ called, and the objects in the former circle release each other. 
Example code to copy from



For a more complete example of using ksets and kobjects properly, see the

sample/kobject/kset-example.c code.
 
example programs samples/kobject/{kobject-example.c,kset-example.c},

which will be built as loadable modules if you select CONFIG_SAMPLE_KOBJECT.

drivers/base/class.c

+2 −0
Original line number Diff line number Diff line
@@ -219,6 +219,8 @@ static void class_create_release(struct class *cls) 
 * This is used to create a struct class pointer that can then be used

 * in calls to device_create().

 *

 * Returns &struct class pointer on success, or ERR_PTR() on error.

 *

 * Note, the pointer created here is to be destroyed when finished by

 * making a call to class_destroy().

 */

drivers/base/core.c

+6 −0
Original line number Diff line number Diff line
@@ -1345,6 +1345,8 @@ static void root_device_release(struct device *dev) 
 * 'module' symlink which points to the @owner directory

 * in sysfs.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: You probably want to use root_device_register().

 */

struct device *__root_device_register(const char *name, struct module *owner)
@@ -1432,6 +1434,8 @@ static void device_create_release(struct device *dev) 
 * Any further sysfs files that might be required can be created using this

 * pointer.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: the struct class passed to this function must have previously

 * been created with a call to class_create().

 */
@@ -1492,6 +1496,8 @@ EXPORT_SYMBOL_GPL(device_create_vargs); 
 * Any further sysfs files that might be required can be created using this

 * pointer.

 *

 * Returns &struct device pointer on success, or ERR_PTR() on error.

 *

 * Note: the struct class passed to this function must have previously

 * been created with a call to class_create().

 */

drivers/base/cpu.c

+8 −8
Original line number Diff line number Diff line
@@ -79,24 +79,24 @@ void unregister_cpu(struct cpu *cpu) 
}



#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE

static ssize_t cpu_probe_store(struct sys_device *dev,

				struct sysdev_attribute *attr,

static ssize_t cpu_probe_store(struct sysdev_class *class,

			       struct sysdev_class_attribute *attr,

			       const char *buf,

			       size_t count)

{

	return arch_cpu_probe(buf, count);

}



static ssize_t cpu_release_store(struct sys_device *dev,

				struct sysdev_attribute *attr,

static ssize_t cpu_release_store(struct sysdev_class *class,

				 struct sysdev_class_attribute *attr,

				 const char *buf,

				 size_t count)

{

	return arch_cpu_release(buf, count);

}



static SYSDEV_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);

static SYSDEV_ATTR(release, S_IWUSR, NULL, cpu_release_store);

static SYSDEV_CLASS_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);

static SYSDEV_CLASS_ATTR(release, S_IWUSR, NULL, cpu_release_store);

#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */



#else /* ... !CONFIG_HOTPLUG_CPU */

drivers/base/firmware_class.c

+2 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ firmware_timeout_show(struct class *class, 
/**

 * firmware_timeout_store - set number of seconds to wait for firmware

 * @class: device class pointer

 * @attr: device attribute pointer

 * @buf: buffer to scan for timeout value

 * @count: number of bytes in @buf

 *
@@ -442,6 +443,7 @@ static int fw_setup_device(struct firmware *fw, struct device **dev_p, 
	fw_priv = dev_get_drvdata(f_dev);



	fw_priv->fw = fw;

	sysfs_bin_attr_init(&fw_priv->attr_data);

	retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);

	if (retval) {

		dev_err(device, "%s: sysfs_create_bin_file failed\n", __func__);