redonkable/remarkable-linux
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sysfs: allocate inode number using ida

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sysfs used simple incrementing allocator which is not guaranteed to be
unique.  This patch makes sysfs use ida to give each sd a unique and
packed inode number.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Tejun Heo 2007-06-14 03:45:13 +09:00 committed by Greg Kroah-Hartman
parent fa7f912ad4
commit 2b611bb7ab
1 changed files with 36 additions and 9 deletions
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45
fs/sysfs/dir.c
View file

@ -9,12 +9,42 @@
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include <asm/semaphore.h>
#include "sysfs.h"
DECLARE_RWSEM(sysfs_rename_sem);
spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED;
static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
static DEFINE_IDA(sysfs_ino_ida);
int sysfs_alloc_ino(ino_t *pino)
{
int ino, rc;
retry:
spin_lock(&sysfs_ino_lock);
rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
spin_unlock(&sysfs_ino_lock);
if (rc == -EAGAIN) {
if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
goto retry;
rc = -ENOMEM;
}
*pino = ino;
return rc;
}
static void sysfs_free_ino(ino_t ino)
{
spin_lock(&sysfs_ino_lock);
ida_remove(&sysfs_ino_ida, ino);
spin_unlock(&sysfs_ino_lock);
}
void release_sysfs_dirent(struct sysfs_dirent * sd)
{
if (sd->s_type & SYSFS_KOBJ_LINK) {
@ -24,6 +54,7 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
kfree(sl);
}
kfree(sd->s_iattr);
sysfs_free_ino(sd->s_ino);
kmem_cache_free(sysfs_dir_cachep, sd);
}
@ -54,14 +85,6 @@ static struct dentry_operations sysfs_dentry_ops = {
.d_iput = sysfs_d_iput,
};
static unsigned int sysfs_inode_counter;
ino_t sysfs_get_inum(void)
{
if (unlikely(sysfs_inode_counter < 3))
sysfs_inode_counter = 3;
return sysfs_inode_counter++;
}
/*
* Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
*/
@ -73,7 +96,11 @@ static struct sysfs_dirent * __sysfs_new_dirent(void * element)
if (!sd)
return NULL;
sd->s_ino = sysfs_get_inum();
if (sysfs_alloc_ino(&sd->s_ino)) {
kmem_cache_free(sysfs_dir_cachep, sd);
return NULL;
}
atomic_set(&sd->s_count, 1);
atomic_set(&sd->s_event, 1);
INIT_LIST_HEAD(&sd->s_children);