ia64/linux-2.6.18-xen.hg

view lib/kobject.c @ 871:9cbcc9008446

xen/x86: don't initialize cpu_data[]'s apicid field on generic code

Afaict, this is not only redundant with the intialization done in
drivers/xen/core/smpboot.c, but actually results - at least for
secondary CPUs - in the Xen-specific value written to be later
overwritten with whatever the generic code determines (with no
guarantee that the two values are identical).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 14 10:09:15 2009 +0100 (2009-05-14)
parents 831230e53067
children
line source
1 /*
2 * kobject.c - library routines for handling generic kernel objects
3 *
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
5 *
6 * This file is released under the GPLv2.
7 *
8 *
9 * Please see the file Documentation/kobject.txt for critical information
10 * about using the kobject interface.
11 */
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
19 /**
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
22 *
23 * Most subsystems have a set of default attributes that
24 * are associated with an object that registers with them.
25 * This is a helper called during object registration that
26 * loops through the default attributes of the subsystem
27 * and creates attributes files for them in sysfs.
28 *
29 */
31 static int populate_dir(struct kobject * kobj)
32 {
33 struct kobj_type * t = get_ktype(kobj);
34 struct attribute * attr;
35 int error = 0;
36 int i;
38 if (t && t->default_attrs) {
39 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
40 if ((error = sysfs_create_file(kobj,attr)))
41 break;
42 }
43 }
44 return error;
45 }
47 static int create_dir(struct kobject * kobj)
48 {
49 int error = 0;
50 if (kobject_name(kobj)) {
51 error = sysfs_create_dir(kobj);
52 if (!error) {
53 if ((error = populate_dir(kobj)))
54 sysfs_remove_dir(kobj);
55 }
56 }
57 return error;
58 }
60 static inline struct kobject * to_kobj(struct list_head * entry)
61 {
62 return container_of(entry,struct kobject,entry);
63 }
65 static int get_kobj_path_length(struct kobject *kobj)
66 {
67 int length = 1;
68 struct kobject * parent = kobj;
70 /* walk up the ancestors until we hit the one pointing to the
71 * root.
72 * Add 1 to strlen for leading '/' of each level.
73 */
74 do {
75 if (kobject_name(parent) == NULL)
76 return 0;
77 length += strlen(kobject_name(parent)) + 1;
78 parent = parent->parent;
79 } while (parent);
80 return length;
81 }
83 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
84 {
85 struct kobject * parent;
87 --length;
88 for (parent = kobj; parent; parent = parent->parent) {
89 int cur = strlen(kobject_name(parent));
90 /* back up enough to print this name with '/' */
91 length -= cur;
92 strncpy (path + length, kobject_name(parent), cur);
93 *(path + --length) = '/';
94 }
96 pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
97 }
99 /**
100 * kobject_get_path - generate and return the path associated with a given kobj
101 * and kset pair. The result must be freed by the caller with kfree().
102 *
103 * @kobj: kobject in question, with which to build the path
104 * @gfp_mask: the allocation type used to allocate the path
105 */
106 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
107 {
108 char *path;
109 int len;
111 len = get_kobj_path_length(kobj);
112 if (len == 0)
113 return NULL;
114 path = kmalloc(len, gfp_mask);
115 if (!path)
116 return NULL;
117 memset(path, 0x00, len);
118 fill_kobj_path(kobj, path, len);
120 return path;
121 }
123 /**
124 * kobject_init - initialize object.
125 * @kobj: object in question.
126 */
127 void kobject_init(struct kobject * kobj)
128 {
129 kref_init(&kobj->kref);
130 INIT_LIST_HEAD(&kobj->entry);
131 init_waitqueue_head(&kobj->poll);
132 kobj->kset = kset_get(kobj->kset);
133 }
136 /**
137 * unlink - remove kobject from kset list.
138 * @kobj: kobject.
139 *
140 * Remove the kobject from the kset list and decrement
141 * its parent's refcount.
142 * This is separated out, so we can use it in both
143 * kobject_del() and kobject_add() on error.
144 */
146 static void unlink(struct kobject * kobj)
147 {
148 if (kobj->kset) {
149 spin_lock(&kobj->kset->list_lock);
150 list_del_init(&kobj->entry);
151 spin_unlock(&kobj->kset->list_lock);
152 }
153 kobject_put(kobj);
154 }
156 /**
157 * kobject_add - add an object to the hierarchy.
158 * @kobj: object.
159 */
161 int kobject_add(struct kobject * kobj)
162 {
163 int error = 0;
164 struct kobject * parent;
166 if (!(kobj = kobject_get(kobj)))
167 return -ENOENT;
168 if (!kobj->k_name)
169 kobj->k_name = kobj->name;
170 if (!kobj->k_name) {
171 pr_debug("kobject attempted to be registered with no name!\n");
172 WARN_ON(1);
173 return -EINVAL;
174 }
175 parent = kobject_get(kobj->parent);
177 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
178 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
179 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
181 if (kobj->kset) {
182 spin_lock(&kobj->kset->list_lock);
184 if (!parent)
185 parent = kobject_get(&kobj->kset->kobj);
187 list_add_tail(&kobj->entry,&kobj->kset->list);
188 spin_unlock(&kobj->kset->list_lock);
189 }
190 kobj->parent = parent;
192 error = create_dir(kobj);
193 if (error) {
194 /* unlink does the kobject_put() for us */
195 unlink(kobj);
196 if (parent)
197 kobject_put(parent);
199 /* be noisy on error issues */
200 if (error == -EEXIST)
201 printk("kobject_add failed for %s with -EEXIST, "
202 "don't try to register things with the "
203 "same name in the same directory.\n",
204 kobject_name(kobj));
205 else
206 printk("kobject_add failed for %s (%d)\n",
207 kobject_name(kobj), error);
208 dump_stack();
209 }
211 return error;
212 }
215 /**
216 * kobject_register - initialize and add an object.
217 * @kobj: object in question.
218 */
220 int kobject_register(struct kobject * kobj)
221 {
222 int error = -EINVAL;
223 if (kobj) {
224 kobject_init(kobj);
225 error = kobject_add(kobj);
226 if (!error)
227 kobject_uevent(kobj, KOBJ_ADD);
228 }
229 return error;
230 }
233 /**
234 * kobject_set_name - Set the name of an object
235 * @kobj: object.
236 * @fmt: format string used to build the name
237 *
238 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
239 * string that @kobj->k_name points to. Otherwise, use the static
240 * @kobj->name array.
241 */
242 int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
243 {
244 int error = 0;
245 int limit = KOBJ_NAME_LEN;
246 int need;
247 va_list args;
248 char * name;
250 /*
251 * First, try the static array
252 */
253 va_start(args,fmt);
254 need = vsnprintf(kobj->name,limit,fmt,args);
255 va_end(args);
256 if (need < limit)
257 name = kobj->name;
258 else {
259 /*
260 * Need more space? Allocate it and try again
261 */
262 limit = need + 1;
263 name = kmalloc(limit,GFP_KERNEL);
264 if (!name) {
265 error = -ENOMEM;
266 goto Done;
267 }
268 va_start(args,fmt);
269 need = vsnprintf(name,limit,fmt,args);
270 va_end(args);
272 /* Still? Give up. */
273 if (need >= limit) {
274 kfree(name);
275 error = -EFAULT;
276 goto Done;
277 }
278 }
280 /* Free the old name, if necessary. */
281 if (kobj->k_name && kobj->k_name != kobj->name)
282 kfree(kobj->k_name);
284 /* Now, set the new name */
285 kobj->k_name = name;
286 Done:
287 return error;
288 }
290 EXPORT_SYMBOL(kobject_set_name);
293 /**
294 * kobject_rename - change the name of an object
295 * @kobj: object in question.
296 * @new_name: object's new name
297 */
299 int kobject_rename(struct kobject * kobj, const char *new_name)
300 {
301 int error = 0;
303 kobj = kobject_get(kobj);
304 if (!kobj)
305 return -EINVAL;
306 error = sysfs_rename_dir(kobj, new_name);
307 kobject_put(kobj);
309 return error;
310 }
312 /**
313 * kobject_del - unlink kobject from hierarchy.
314 * @kobj: object.
315 */
317 void kobject_del(struct kobject * kobj)
318 {
319 sysfs_remove_dir(kobj);
320 unlink(kobj);
321 }
323 /**
324 * kobject_unregister - remove object from hierarchy and decrement refcount.
325 * @kobj: object going away.
326 */
328 void kobject_unregister(struct kobject * kobj)
329 {
330 pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
331 kobject_uevent(kobj, KOBJ_REMOVE);
332 kobject_del(kobj);
333 kobject_put(kobj);
334 }
336 /**
337 * kobject_get - increment refcount for object.
338 * @kobj: object.
339 */
341 struct kobject * kobject_get(struct kobject * kobj)
342 {
343 if (kobj)
344 kref_get(&kobj->kref);
345 return kobj;
346 }
348 /**
349 * kobject_cleanup - free kobject resources.
350 * @kobj: object.
351 */
353 void kobject_cleanup(struct kobject * kobj)
354 {
355 struct kobj_type * t = get_ktype(kobj);
356 struct kset * s = kobj->kset;
357 struct kobject * parent = kobj->parent;
359 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
360 if (kobj->k_name != kobj->name)
361 kfree(kobj->k_name);
362 kobj->k_name = NULL;
363 if (t && t->release)
364 t->release(kobj);
365 if (s)
366 kset_put(s);
367 if (parent)
368 kobject_put(parent);
369 }
371 static void kobject_release(struct kref *kref)
372 {
373 kobject_cleanup(container_of(kref, struct kobject, kref));
374 }
376 /**
377 * kobject_put - decrement refcount for object.
378 * @kobj: object.
379 *
380 * Decrement the refcount, and if 0, call kobject_cleanup().
381 */
382 void kobject_put(struct kobject * kobj)
383 {
384 if (kobj)
385 kref_put(&kobj->kref, kobject_release);
386 }
389 static void dir_release(struct kobject *kobj)
390 {
391 kfree(kobj);
392 }
394 static struct kobj_type dir_ktype = {
395 .release = dir_release,
396 .sysfs_ops = NULL,
397 .default_attrs = NULL,
398 };
400 /**
401 * kobject_add_dir - add sub directory of object.
402 * @parent: object in which a directory is created.
403 * @name: directory name.
404 *
405 * Add a plain directory object as child of given object.
406 */
407 struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
408 {
409 struct kobject *k;
411 if (!parent)
412 return NULL;
414 k = kzalloc(sizeof(*k), GFP_KERNEL);
415 if (!k)
416 return NULL;
418 k->parent = parent;
419 k->ktype = &dir_ktype;
420 kobject_set_name(k, name);
421 kobject_register(k);
423 return k;
424 }
426 /**
427 * kset_init - initialize a kset for use
428 * @k: kset
429 */
431 void kset_init(struct kset * k)
432 {
433 kobject_init(&k->kobj);
434 INIT_LIST_HEAD(&k->list);
435 spin_lock_init(&k->list_lock);
436 }
439 /**
440 * kset_add - add a kset object to the hierarchy.
441 * @k: kset.
442 *
443 * Simply, this adds the kset's embedded kobject to the
444 * hierarchy.
445 * We also try to make sure that the kset's embedded kobject
446 * has a parent before it is added. We only care if the embedded
447 * kobject is not part of a kset itself, since kobject_add()
448 * assigns a parent in that case.
449 * If that is the case, and the kset has a controlling subsystem,
450 * then we set the kset's parent to be said subsystem.
451 */
453 int kset_add(struct kset * k)
454 {
455 if (!k->kobj.parent && !k->kobj.kset && k->subsys)
456 k->kobj.parent = &k->subsys->kset.kobj;
458 return kobject_add(&k->kobj);
459 }
462 /**
463 * kset_register - initialize and add a kset.
464 * @k: kset.
465 */
467 int kset_register(struct kset * k)
468 {
469 kset_init(k);
470 return kset_add(k);
471 }
474 /**
475 * kset_unregister - remove a kset.
476 * @k: kset.
477 */
479 void kset_unregister(struct kset * k)
480 {
481 kobject_unregister(&k->kobj);
482 }
485 /**
486 * kset_find_obj - search for object in kset.
487 * @kset: kset we're looking in.
488 * @name: object's name.
489 *
490 * Lock kset via @kset->subsys, and iterate over @kset->list,
491 * looking for a matching kobject. If matching object is found
492 * take a reference and return the object.
493 */
495 struct kobject * kset_find_obj(struct kset * kset, const char * name)
496 {
497 struct list_head * entry;
498 struct kobject * ret = NULL;
500 spin_lock(&kset->list_lock);
501 list_for_each(entry,&kset->list) {
502 struct kobject * k = to_kobj(entry);
503 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
504 ret = kobject_get(k);
505 break;
506 }
507 }
508 spin_unlock(&kset->list_lock);
509 return ret;
510 }
513 void subsystem_init(struct subsystem * s)
514 {
515 init_rwsem(&s->rwsem);
516 kset_init(&s->kset);
517 }
519 /**
520 * subsystem_register - register a subsystem.
521 * @s: the subsystem we're registering.
522 *
523 * Once we register the subsystem, we want to make sure that
524 * the kset points back to this subsystem for correct usage of
525 * the rwsem.
526 */
528 int subsystem_register(struct subsystem * s)
529 {
530 int error;
532 subsystem_init(s);
533 pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
535 if (!(error = kset_add(&s->kset))) {
536 if (!s->kset.subsys)
537 s->kset.subsys = s;
538 }
539 return error;
540 }
542 void subsystem_unregister(struct subsystem * s)
543 {
544 pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
545 kset_unregister(&s->kset);
546 }
549 /**
550 * subsystem_create_file - export sysfs attribute file.
551 * @s: subsystem.
552 * @a: subsystem attribute descriptor.
553 */
555 int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
556 {
557 int error = 0;
558 if (subsys_get(s)) {
559 error = sysfs_create_file(&s->kset.kobj,&a->attr);
560 subsys_put(s);
561 }
562 return error;
563 }
566 /**
567 * subsystem_remove_file - remove sysfs attribute file.
568 * @s: subsystem.
569 * @a: attribute desciptor.
570 */
571 #if 0
572 void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
573 {
574 if (subsys_get(s)) {
575 sysfs_remove_file(&s->kset.kobj,&a->attr);
576 subsys_put(s);
577 }
578 }
579 #endif /* 0 */
581 EXPORT_SYMBOL(kobject_init);
582 EXPORT_SYMBOL(kobject_register);
583 EXPORT_SYMBOL(kobject_unregister);
584 EXPORT_SYMBOL(kobject_get);
585 EXPORT_SYMBOL(kobject_put);
586 EXPORT_SYMBOL(kobject_add);
587 EXPORT_SYMBOL(kobject_del);
589 EXPORT_SYMBOL(kset_register);
590 EXPORT_SYMBOL(kset_unregister);
592 EXPORT_SYMBOL(subsystem_register);
593 EXPORT_SYMBOL(subsystem_unregister);
594 EXPORT_SYMBOL(subsys_create_file);