Commit 2b611bb7 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

sysfs: allocate inode number using ida 



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: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent fa7f912a

fs/sysfs/dir.c

+36 −9
Original line number Diff line number Diff line
@@ -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);