[deliverable/linux.git] / fs / sysfs / dir.c

/*
 * dir.c - Operations for sysfs directories.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include "sysfs.h"

DEFINE_MUTEX(sysfs_mutex);
spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;

static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
static DEFINE_IDA(sysfs_ino_ida);

/**
 *	sysfs_link_sibling - link sysfs_dirent into sibling list
 *	@sd: sysfs_dirent of interest
 *
 *	Link @sd into its sibling list which starts from
 *	sd->s_parent->s_children.
 *
 *	Locking:
 *	mutex_lock(sysfs_mutex)
 */
static void sysfs_link_sibling(struct sysfs_dirent *sd)
{
	struct sysfs_dirent *parent_sd = sd->s_parent;

	BUG_ON(sd->s_sibling);
	sd->s_sibling = parent_sd->s_children;
	parent_sd->s_children = sd;
}

/**
 *	sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
 *	@sd: sysfs_dirent of interest
 *
 *	Unlink @sd from its sibling list which starts from
 *	sd->s_parent->s_children.
 *
 *	Locking:
 *	mutex_lock(sysfs_mutex)
 */
static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
{
	struct sysfs_dirent **pos;

	for (pos = &sd->s_parent->s_children; *pos; pos = &(*pos)->s_sibling) {
		if (*pos == sd) {
			*pos = sd->s_sibling;
			sd->s_sibling = NULL;
			break;
		}
	}
}

/**
 *	sysfs_get_dentry - get dentry for the given sysfs_dirent
 *	@sd: sysfs_dirent of interest
 *
 *	Get dentry for @sd.  Dentry is looked up if currently not
 *	present.  This function climbs sysfs_dirent tree till it
 *	reaches a sysfs_dirent with valid dentry attached and descends
 *	down from there looking up dentry for each step.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 *
 *	RETURNS:
 *	Pointer to found dentry on success, ERR_PTR() value on error.
 */
struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd)
{
	struct sysfs_dirent *cur;
	struct dentry *parent_dentry, *dentry;
	int i, depth;

	/* Find the first parent which has valid s_dentry and get the
	 * dentry.
	 */
	mutex_lock(&sysfs_mutex);
 restart0:
	spin_lock(&sysfs_assoc_lock);
 restart1:
	spin_lock(&dcache_lock);

	dentry = NULL;
	depth = 0;
	cur = sd;
	while (!cur->s_dentry || !cur->s_dentry->d_inode) {
		if (cur->s_flags & SYSFS_FLAG_REMOVED) {
			dentry = ERR_PTR(-ENOENT);
			depth = 0;
			break;
		}
		cur = cur->s_parent;
		depth++;
	}
	if (!IS_ERR(dentry))
		dentry = dget_locked(cur->s_dentry);

	spin_unlock(&dcache_lock);
	spin_unlock(&sysfs_assoc_lock);

	/* from the found dentry, look up depth times */
	while (depth--) {
		/* find and get depth'th ancestor */
		for (cur = sd, i = 0; cur && i < depth; i++)
			cur = cur->s_parent;

		/* This can happen if tree structure was modified due
		 * to move/rename.  Restart.
		 */
		if (i != depth) {
			dput(dentry);
			goto restart0;
		}

		sysfs_get(cur);

		mutex_unlock(&sysfs_mutex);

		/* look it up */
		parent_dentry = dentry;
		mutex_lock(&parent_dentry->d_inode->i_mutex);
		dentry = lookup_one_len_kern(cur->s_name, parent_dentry,
					     strlen(cur->s_name));
		mutex_unlock(&parent_dentry->d_inode->i_mutex);
		dput(parent_dentry);

		if (IS_ERR(dentry)) {
			sysfs_put(cur);
			return dentry;
		}

		mutex_lock(&sysfs_mutex);
		spin_lock(&sysfs_assoc_lock);

		/* This, again, can happen if tree structure has
		 * changed and we looked up the wrong thing.  Restart.
		 */
		if (cur->s_dentry != dentry) {
			dput(dentry);
			sysfs_put(cur);
			goto restart1;
		}

		spin_unlock(&sysfs_assoc_lock);

		sysfs_put(cur);
	}

	mutex_unlock(&sysfs_mutex);
	return dentry;
}

/**
 *	sysfs_get_active - get an active reference to sysfs_dirent
 *	@sd: sysfs_dirent to get an active reference to
 *
 *	Get an active reference of @sd.  This function is noop if @sd
 *	is NULL.
 *
 *	RETURNS:
 *	Pointer to @sd on success, NULL on failure.
 */
struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
	if (unlikely(!sd))
		return NULL;

	while (1) {
		int v, t;

		v = atomic_read(&sd->s_active);
		if (unlikely(v < 0))
			return NULL;

		t = atomic_cmpxchg(&sd->s_active, v, v + 1);
		if (likely(t == v))
			return sd;
		if (t < 0)
			return NULL;

		cpu_relax();
	}
}

/**
 *	sysfs_put_active - put an active reference to sysfs_dirent
 *	@sd: sysfs_dirent to put an active reference to
 *
 *	Put an active reference to @sd.  This function is noop if @sd
 *	is NULL.
 */
void sysfs_put_active(struct sysfs_dirent *sd)
{
	struct completion *cmpl;
	int v;

	if (unlikely(!sd))
		return;

	v = atomic_dec_return(&sd->s_active);
	if (likely(v != SD_DEACTIVATED_BIAS))
		return;

	/* atomic_dec_return() is a mb(), we'll always see the updated
	 * sd->s_sibling.
	 */
	cmpl = (void *)sd->s_sibling;
	complete(cmpl);
}

/**
 *	sysfs_get_active_two - get active references to sysfs_dirent and parent
 *	@sd: sysfs_dirent of interest
 *
 *	Get active reference to @sd and its parent.  Parent's active
 *	reference is grabbed first.  This function is noop if @sd is
 *	NULL.
 *
 *	RETURNS:
 *	Pointer to @sd on success, NULL on failure.
 */
struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd)
{
	if (sd) {
		if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
			return NULL;
		if (unlikely(!sysfs_get_active(sd))) {
			sysfs_put_active(sd->s_parent);
			return NULL;
		}
	}
	return sd;
}

/**
 *	sysfs_put_active_two - put active references to sysfs_dirent and parent
 *	@sd: sysfs_dirent of interest
 *
 *	Put active references to @sd and its parent.  This function is
 *	noop if @sd is NULL.
 */
void sysfs_put_active_two(struct sysfs_dirent *sd)
{
	if (sd) {
		sysfs_put_active(sd);
		sysfs_put_active(sd->s_parent);
	}
}

/**
 *	sysfs_deactivate - deactivate sysfs_dirent
 *	@sd: sysfs_dirent to deactivate
 *
 *	Deny new active references and drain existing ones.
 */
static void sysfs_deactivate(struct sysfs_dirent *sd)
{
	DECLARE_COMPLETION_ONSTACK(wait);
	int v;

	BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
	sd->s_sibling = (void *)&wait;

	/* atomic_add_return() is a mb(), put_active() will always see
	 * the updated sd->s_sibling.
	 */
	v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);

	if (v != SD_DEACTIVATED_BIAS)
		wait_for_completion(&wait);

	sd->s_sibling = NULL;
}

static 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)
{
	struct sysfs_dirent *parent_sd;

 repeat:
	/* Moving/renaming is always done while holding reference.
	 * sd->s_parent won't change beneath us.
	 */
	parent_sd = sd->s_parent;

	if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
		sysfs_put(sd->s_elem.symlink.target_sd);
	if (sysfs_type(sd) & SYSFS_COPY_NAME)
		kfree(sd->s_name);
	kfree(sd->s_iattr);
	sysfs_free_ino(sd->s_ino);
	kmem_cache_free(sysfs_dir_cachep, sd);

	sd = parent_sd;
	if (sd && atomic_dec_and_test(&sd->s_count))
		goto repeat;
}

static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
{
	struct sysfs_dirent * sd = dentry->d_fsdata;

	if (sd) {
		/* sd->s_dentry is protected with sysfs_assoc_lock.
		 * This allows sysfs_drop_dentry() to dereference it.
		 */
		spin_lock(&sysfs_assoc_lock);

		/* The dentry might have been deleted or another
		 * lookup could have happened updating sd->s_dentry to
		 * point the new dentry.  Ignore if it isn't pointing
		 * to this dentry.
		 */
		if (sd->s_dentry == dentry)
			sd->s_dentry = NULL;
		spin_unlock(&sysfs_assoc_lock);
		sysfs_put(sd);
	}
	iput(inode);
}

static struct dentry_operations sysfs_dentry_ops = {
	.d_iput		= sysfs_d_iput,
};

struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
{
	char *dup_name = NULL;
	struct sysfs_dirent *sd;

	if (type & SYSFS_COPY_NAME) {
		name = dup_name = kstrdup(name, GFP_KERNEL);
		if (!name)
			return NULL;
	}

	sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
	if (!sd)
		goto err_out1;

	if (sysfs_alloc_ino(&sd->s_ino))
		goto err_out2;

	atomic_set(&sd->s_count, 1);
	atomic_set(&sd->s_active, 0);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* dir.c - Operations for sysfs directories.
	3	*/
	4
	5	#undef DEBUG
	6
	7	#include <linux/fs.h>
	8	#include <linux/mount.h>
	9	#include <linux/module.h>
	10	#include <linux/kobject.h>
5f45f1a7	11	#include <linux/namei.h>
2b611bb7	12	#include <linux/idr.h>
8619f979	13	#include <linux/completion.h>
869512ab	14	#include <linux/mutex.h>
1da177e4 LT	15	#include "sysfs.h"
1da177e4 LT	16
3007e997	17	DEFINE_MUTEX(sysfs_mutex);
5f995323	18	spinlock_t sysfs_assoc_lock = SPIN_LOCK_UNLOCKED;
1da177e4	19
2b611bb7 TH	20	static spinlock_t sysfs_ino_lock = SPIN_LOCK_UNLOCKED;
	21	static DEFINE_IDA(sysfs_ino_ida);
	22
0c73f18b TH	23	/**
	24	* sysfs_link_sibling - link sysfs_dirent into sibling list
	25	* @sd: sysfs_dirent of interest
	26	*
	27	* Link @sd into its sibling list which starts from
	28	* sd->s_parent->s_children.
	29	*
	30	* Locking:
3007e997	31	* mutex_lock(sysfs_mutex)
0c73f18b	32	*/
41fc1c27	33	static void sysfs_link_sibling(struct sysfs_dirent *sd)
0c73f18b TH	34	{
	35	struct sysfs_dirent *parent_sd = sd->s_parent;
	36
	37	BUG_ON(sd->s_sibling);
	38	sd->s_sibling = parent_sd->s_children;
	39	parent_sd->s_children = sd;
	40	}
	41
	42	/**
	43	* sysfs_unlink_sibling - unlink sysfs_dirent from sibling list
	44	* @sd: sysfs_dirent of interest
	45	*
	46	* Unlink @sd from its sibling list which starts from
	47	* sd->s_parent->s_children.
	48	*
	49	* Locking:
3007e997	50	* mutex_lock(sysfs_mutex)
0c73f18b	51	*/
41fc1c27	52	static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
0c73f18b TH	53	{
	54	struct sysfs_dirent **pos;
	55
	56	for (pos = &sd->s_parent->s_children; pos; pos = &(pos)->s_sibling) {
	57	if (*pos == sd) {
	58	*pos = sd->s_sibling;
	59	sd->s_sibling = NULL;
	60	break;
	61	}
	62	}
	63	}
	64
53e0ae92 TH	65	/**
	66	* sysfs_get_dentry - get dentry for the given sysfs_dirent
	67	* @sd: sysfs_dirent of interest
	68	*
	69	* Get dentry for @sd. Dentry is looked up if currently not
	70	* present. This function climbs sysfs_dirent tree till it
	71	* reaches a sysfs_dirent with valid dentry attached and descends
	72	* down from there looking up dentry for each step.
	73	*
	74	* LOCKING:
	75	* Kernel thread context (may sleep)
	76	*
	77	* RETURNS:
	78	* Pointer to found dentry on success, ERR_PTR() value on error.
	79	*/
	80	struct dentry sysfs_get_dentry(struct sysfs_dirent sd)
	81	{
	82	struct sysfs_dirent *cur;
	83	struct dentry parent_dentry, dentry;
	84	int i, depth;
	85
	86	/* Find the first parent which has valid s_dentry and get the
	87	* dentry.
	88	*/
	89	mutex_lock(&sysfs_mutex);
	90	restart0:
	91	spin_lock(&sysfs_assoc_lock);
	92	restart1:
	93	spin_lock(&dcache_lock);
	94
	95	dentry = NULL;
	96	depth = 0;
	97	cur = sd;
	98	while (!cur->s_dentry \|\| !cur->s_dentry->d_inode) {
	99	if (cur->s_flags & SYSFS_FLAG_REMOVED) {
	100	dentry = ERR_PTR(-ENOENT);
	101	depth = 0;
	102	break;
	103	}
	104	cur = cur->s_parent;
	105	depth++;
	106	}
	107	if (!IS_ERR(dentry))
	108	dentry = dget_locked(cur->s_dentry);
	109
	110	spin_unlock(&dcache_lock);
	111	spin_unlock(&sysfs_assoc_lock);
	112
	113	/* from the found dentry, look up depth times */
	114	while (depth--) {
	115	/* find and get depth'th ancestor */
	116	for (cur = sd, i = 0; cur && i < depth; i++)
	117	cur = cur->s_parent;
	118
	119	/* This can happen if tree structure was modified due
	120	* to move/rename. Restart.
	121	*/
	122	if (i != depth) {
	123	dput(dentry);
	124	goto restart0;
	125	}
	126
	127	sysfs_get(cur);
	128
129	mutex_unlock(&sysfs_mutex);
130
131	/* look it up */
132	parent_dentry = dentry;
25328026	133	mutex_lock(&parent_dentry->d_inode->i_mutex);
53e0ae92 TH	134	dentry = lookup_one_len_kern(cur->s_name, parent_dentry,
53e0ae92 TH	135	strlen(cur->s_name));
25328026	136	mutex_unlock(&parent_dentry->d_inode->i_mutex);
53e0ae92 TH	137	dput(parent_dentry);
	138
	139	if (IS_ERR(dentry)) {
	140	sysfs_put(cur);
	141	return dentry;
	142	}
	143
	144	mutex_lock(&sysfs_mutex);
	145	spin_lock(&sysfs_assoc_lock);
	146
	147	/* This, again, can happen if tree structure has
	148	* changed and we looked up the wrong thing. Restart.
	149	*/
	150	if (cur->s_dentry != dentry) {
	151	dput(dentry);
	152	sysfs_put(cur);
	153	goto restart1;
	154	}
	155
	156	spin_unlock(&sysfs_assoc_lock);
	157
	158	sysfs_put(cur);
	159	}
	160
	161	mutex_unlock(&sysfs_mutex);
	162	return dentry;
	163	}
	164
b6b4a439 TH	165	/**
	166	* sysfs_get_active - get an active reference to sysfs_dirent
	167	* @sd: sysfs_dirent to get an active reference to
	168	*
	169	* Get an active reference of @sd. This function is noop if @sd
	170	* is NULL.
	171	*
	172	* RETURNS:
	173	* Pointer to @sd on success, NULL on failure.
	174	*/
	175	struct sysfs_dirent sysfs_get_active(struct sysfs_dirent sd)
	176	{
8619f979 TH	177	if (unlikely(!sd))
	178	return NULL;
	179
	180	while (1) {
	181	int v, t;
	182
	183	v = atomic_read(&sd->s_active);
	184	if (unlikely(v < 0))
	185	return NULL;
	186
	187	t = atomic_cmpxchg(&sd->s_active, v, v + 1);
	188	if (likely(t == v))
	189	return sd;
	190	if (t < 0)
	191	return NULL;
	192
	193	cpu_relax();
b6b4a439	194	}
b6b4a439 TH	195	}
	196
	197	/**
	198	* sysfs_put_active - put an active reference to sysfs_dirent
	199	* @sd: sysfs_dirent to put an active reference to
	200	*
	201	* Put an active reference to @sd. This function is noop if @sd
	202	* is NULL.
	203	*/
	204	void sysfs_put_active(struct sysfs_dirent *sd)
	205	{
8619f979 TH	206	struct completion *cmpl;
	207	int v;
	208
	209	if (unlikely(!sd))
	210	return;
	211
	212	v = atomic_dec_return(&sd->s_active);
	213	if (likely(v != SD_DEACTIVATED_BIAS))
	214	return;
	215
	216	/* atomic_dec_return() is a mb(), we'll always see the updated
0c73f18b	217	* sd->s_sibling.
8619f979	218	*/
0c73f18b	219	cmpl = (void *)sd->s_sibling;
8619f979	220	complete(cmpl);
b6b4a439 TH	221	}
	222
	223	/**
	224	* sysfs_get_active_two - get active references to sysfs_dirent and parent
	225	* @sd: sysfs_dirent of interest
	226	*
	227	* Get active reference to @sd and its parent. Parent's active
	228	* reference is grabbed first. This function is noop if @sd is
	229	* NULL.
	230	*
	231	* RETURNS:
	232	* Pointer to @sd on success, NULL on failure.
	233	*/
	234	struct sysfs_dirent sysfs_get_active_two(struct sysfs_dirent sd)
	235	{
	236	if (sd) {
	237	if (sd->s_parent && unlikely(!sysfs_get_active(sd->s_parent)))
	238	return NULL;
	239	if (unlikely(!sysfs_get_active(sd))) {
	240	sysfs_put_active(sd->s_parent);
	241	return NULL;
	242	}
	243	}
	244	return sd;
	245	}
	246
	247	/**
	248	* sysfs_put_active_two - put active references to sysfs_dirent and parent
	249	* @sd: sysfs_dirent of interest
	250	*
	251	* Put active references to @sd and its parent. This function is
	252	* noop if @sd is NULL.
	253	*/
	254	void sysfs_put_active_two(struct sysfs_dirent *sd)
	255	{
	256	if (sd) {
	257	sysfs_put_active(sd);
	258	sysfs_put_active(sd->s_parent);
	259	}
	260	}
	261
	262	/**
	263	* sysfs_deactivate - deactivate sysfs_dirent
	264	* @sd: sysfs_dirent to deactivate
	265	*
8619f979	266	* Deny new active references and drain existing ones.
b6b4a439	267	*/
fb6896da	268	static void sysfs_deactivate(struct sysfs_dirent *sd)
b6b4a439	269	{
8619f979 TH	270	DECLARE_COMPLETION_ONSTACK(wait);
8619f979 TH	271	int v;
b6b4a439	272
380e6fbb	273	BUG_ON(sd->s_sibling \|\| !(sd->s_flags & SYSFS_FLAG_REMOVED));
0c73f18b	274	sd->s_sibling = (void *)&wait;
8619f979 TH	275
8619f979 TH	276	/* atomic_add_return() is a mb(), put_active() will always see
0c73f18b	277	* the updated sd->s_sibling.
b6b4a439	278	*/
8619f979 TH	279	v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
	280
	281	if (v != SD_DEACTIVATED_BIAS)
	282	wait_for_completion(&wait);
	283
0c73f18b	284	sd->s_sibling = NULL;
b6b4a439 TH	285	}
b6b4a439 TH	286
42b37df6	287	static int sysfs_alloc_ino(ino_t *pino)
2b611bb7 TH	288	{
	289	int ino, rc;
	290
	291	retry:
	292	spin_lock(&sysfs_ino_lock);
	293	rc = ida_get_new_above(&sysfs_ino_ida, 2, &ino);
	294	spin_unlock(&sysfs_ino_lock);
	295
	296	if (rc == -EAGAIN) {
	297	if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
	298	goto retry;
	299	rc = -ENOMEM;
	300	}
	301
	302	*pino = ino;
	303	return rc;
	304	}
	305
	306	static void sysfs_free_ino(ino_t ino)
	307	{
	308	spin_lock(&sysfs_ino_lock);
	309	ida_remove(&sysfs_ino_ida, ino);
	310	spin_unlock(&sysfs_ino_lock);
	311	}
	312
fa7f912a TH	313	void release_sysfs_dirent(struct sysfs_dirent * sd)
fa7f912a TH	314	{
13b3086d TH	315	struct sysfs_dirent *parent_sd;
	316
	317	repeat:
3007e997 TH	318	/* Moving/renaming is always done while holding reference.
	319	* sd->s_parent won't change beneath us.
	320	*/
13b3086d TH	321	parent_sd = sd->s_parent;
13b3086d TH	322
b402d72c	323	if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
2b29ac25	324	sysfs_put(sd->s_elem.symlink.target_sd);
b402d72c	325	if (sysfs_type(sd) & SYSFS_COPY_NAME)
0c096b50	326	kfree(sd->s_name);
fa7f912a	327	kfree(sd->s_iattr);
2b611bb7	328	sysfs_free_ino(sd->s_ino);
fa7f912a	329	kmem_cache_free(sysfs_dir_cachep, sd);
13b3086d TH	330
	331	sd = parent_sd;
	332	if (sd && atomic_dec_and_test(&sd->s_count))
	333	goto repeat;
fa7f912a TH	334	}
fa7f912a TH	335
1da177e4 LT	336	static void sysfs_d_iput(struct dentry * dentry, struct inode * inode)
	337	{
	338	struct sysfs_dirent * sd = dentry->d_fsdata;
	339
	340	if (sd) {
5f995323 TH	341	/* sd->s_dentry is protected with sysfs_assoc_lock.
5f995323 TH	342	* This allows sysfs_drop_dentry() to dereference it.
dd14cbc9	343	*/
5f995323	344	spin_lock(&sysfs_assoc_lock);
dd14cbc9 TH	345
	346	/* The dentry might have been deleted or another
	347	* lookup could have happened updating sd->s_dentry to
	348	* point the new dentry. Ignore if it isn't pointing
	349	* to this dentry.
	350	*/
	351	if (sd->s_dentry == dentry)
	352	sd->s_dentry = NULL;
5f995323	353	spin_unlock(&sysfs_assoc_lock);
1da177e4 LT	354	sysfs_put(sd);
	355	}
	356	iput(inode);
	357	}
	358
	359	static struct dentry_operations sysfs_dentry_ops = {
	360	.d_iput = sysfs_d_iput,
	361	};
	362
3e519038	363	struct sysfs_dirent sysfs_new_dirent(const char name, umode_t mode, int type)
1da177e4	364	{
0c096b50	365	char *dup_name = NULL;
01da2425	366	struct sysfs_dirent *sd;
0c096b50 TH	367
	368	if (type & SYSFS_COPY_NAME) {
	369	name = dup_name = kstrdup(name, GFP_KERNEL);
	370	if (!name)
01da2425	371	return NULL;
0c096b50	372	}
1da177e4	373
c3762229	374	sd = kmem_cache_zalloc(sysfs_dir_cachep, GFP_KERNEL);
1da177e4	375	if (!sd)
01da2425	376	goto err_out1;
1da177e4	377
0c096b50	378	if (sysfs_alloc_ino(&sd->s_ino))
01da2425	379	goto err_out2;
2b611bb7	380
1da177e4	381	atomic_set(&sd->s_count, 1);
8619f979	382	atomic_set(&sd->s_active, 0);