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-rw-r--r--fs/sysfs/file.c67
1 files changed, 11 insertions, 56 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index b834f1709f9f..a271c87c4472 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -20,43 +20,6 @@
20 20
21#include "sysfs.h" 21#include "sysfs.h"
22 22
23#define to_sattr(a) container_of(a,struct subsys_attribute, attr)
24
25/*
26 * Subsystem file operations.
27 * These operations allow subsystems to have files that can be
28 * read/written.
29 */
30static ssize_t
31subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page)
32{
33 struct kset *kset = to_kset(kobj);
34 struct subsys_attribute * sattr = to_sattr(attr);
35 ssize_t ret = -EIO;
36
37 if (sattr->show)
38 ret = sattr->show(kset, page);
39 return ret;
40}
41
42static ssize_t
43subsys_attr_store(struct kobject * kobj, struct attribute * attr,
44 const char * page, size_t count)
45{
46 struct kset *kset = to_kset(kobj);
47 struct subsys_attribute * sattr = to_sattr(attr);
48 ssize_t ret = -EIO;
49
50 if (sattr->store)
51 ret = sattr->store(kset, page, count);
52 return ret;
53}
54
55static struct sysfs_ops subsys_sysfs_ops = {
56 .show = subsys_attr_show,
57 .store = subsys_attr_store,
58};
59
60/* 23/*
61 * There's one sysfs_buffer for each open file and one 24 * There's one sysfs_buffer for each open file and one
62 * sysfs_open_dirent for each sysfs_dirent with one or more open 25 * sysfs_open_dirent for each sysfs_dirent with one or more open
@@ -66,7 +29,7 @@ static struct sysfs_ops subsys_sysfs_ops = {
66 * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open 29 * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open
67 * is protected by sysfs_open_dirent_lock. 30 * is protected by sysfs_open_dirent_lock.
68 */ 31 */
69static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED; 32static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
70 33
71struct sysfs_open_dirent { 34struct sysfs_open_dirent {
72 atomic_t refcnt; 35 atomic_t refcnt;
@@ -354,31 +317,23 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
354{ 317{
355 struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; 318 struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
356 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; 319 struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
357 struct sysfs_buffer * buffer; 320 struct sysfs_buffer *buffer;
358 struct sysfs_ops * ops = NULL; 321 struct sysfs_ops *ops;
359 int error; 322 int error = -EACCES;
360 323
361 /* need attr_sd for attr and ops, its parent for kobj */ 324 /* need attr_sd for attr and ops, its parent for kobj */
362 if (!sysfs_get_active_two(attr_sd)) 325 if (!sysfs_get_active_two(attr_sd))
363 return -ENODEV; 326 return -ENODEV;
364 327
365 /* if the kobject has no ktype, then we assume that it is a subsystem 328 /* every kobject with an attribute needs a ktype assigned */
366 * itself, and use ops for it. 329 if (kobj->ktype && kobj->ktype->sysfs_ops)
367 */
368 if (kobj->kset && kobj->kset->ktype)
369 ops = kobj->kset->ktype->sysfs_ops;
370 else if (kobj->ktype)
371 ops = kobj->ktype->sysfs_ops; 330 ops = kobj->ktype->sysfs_ops;
372 else 331 else {
373 ops = &subsys_sysfs_ops; 332 printk(KERN_ERR "missing sysfs attribute operations for "
374 333 "kobject: %s\n", kobject_name(kobj));
375 error = -EACCES; 334 WARN_ON(1);
376
377 /* No sysfs operations, either from having no subsystem,
378 * or the subsystem have no operations.
379 */
380 if (!ops)
381 goto err_out; 335 goto err_out;
336 }
382 337
383 /* File needs write support. 338 /* File needs write support.
384 * The inode's perms must say it's ok, 339 * The inode's perms must say it's ok,