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sysfs, kernfs: introduce kernfs[_find_and]_get() and kernfs_put()

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Introduce kernfs interface for finding, getting and putting
sysfs_dirents.

* sysfs_find_dirent() is renamed to kernfs_find_ns() and lockdep
  assertion for sysfs_mutex is added.

* sysfs_get_dirent_ns() is renamed to kernfs_find_and_get().

* Macro inline dancing around __sysfs_get/put() are removed and
  kernfs_get/put() are made proper functions implemented in
  fs/sysfs/dir.c.

While the conversions are mostly equivalent, there's one difference -
kernfs_get() doesn't return the input param as its return value.  This
change is intentional.  While passing through the input increases
writability in some areas, it is unnecessary and has been shown to
cause confusion regarding how the last ref is handled.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo 2013-11-28 14:54:30 -05:00 committed by Greg Kroah-Hartman
parent 517e64f578
commit ccf73cf336
9 changed files with 154 additions and 151 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

117
fs/sysfs/dir.c
View file

@ -240,10 +240,31 @@ static void sysfs_free_ino(unsigned int ino)
spin_unlock(&sysfs_ino_lock); spin_unlock(&sysfs_ino_lock);
} }
void release_sysfs_dirent(struct sysfs_dirent *sd) /**
* kernfs_get - get a reference count on a sysfs_dirent
* @sd: the target sysfs_dirent
*/
void kernfs_get(struct sysfs_dirent *sd)
{
if (sd) {
WARN_ON(!atomic_read(&sd->s_count));
atomic_inc(&sd->s_count);
}
}
EXPORT_SYMBOL_GPL(kernfs_get);
/**
* kernfs_put - put a reference count on a sysfs_dirent
* @sd: the target sysfs_dirent
*
* Put a reference count of @sd and destroy it if it reached zero.
*/
void kernfs_put(struct sysfs_dirent *sd)
{ {
struct sysfs_dirent *parent_sd; struct sysfs_dirent *parent_sd;
if (!sd || !atomic_dec_and_test(&sd->s_count))
return;
repeat: repeat:
/* Moving/renaming is always done while holding reference. /* Moving/renaming is always done while holding reference.
* sd->s_parent won't change beneath us. * sd->s_parent won't change beneath us.
@ -255,7 +276,7 @@ void release_sysfs_dirent(struct sysfs_dirent *sd)
parent_sd ? parent_sd->s_name : "", sd->s_name); parent_sd ? parent_sd->s_name : "", sd->s_name);
if (sysfs_type(sd) == SYSFS_KOBJ_LINK) if (sysfs_type(sd) == SYSFS_KOBJ_LINK)
sysfs_put(sd->s_symlink.target_sd); kernfs_put(sd->s_symlink.target_sd);
if (sysfs_type(sd) & SYSFS_COPY_NAME) if (sysfs_type(sd) & SYSFS_COPY_NAME)
kfree(sd->s_name); kfree(sd->s_name);
if (sd->s_iattr && sd->s_iattr->ia_secdata) if (sd->s_iattr && sd->s_iattr->ia_secdata)
@ -269,6 +290,7 @@ void release_sysfs_dirent(struct sysfs_dirent *sd)
if (sd && atomic_dec_and_test(&sd->s_count)) if (sd && atomic_dec_and_test(&sd->s_count))
goto repeat; goto repeat;
} }
EXPORT_SYMBOL_GPL(kernfs_put);
static int sysfs_dentry_delete(const struct dentry *dentry) static int sysfs_dentry_delete(const struct dentry *dentry)
{ {
@ -331,7 +353,7 @@ out_bad:
static void sysfs_dentry_release(struct dentry *dentry) static void sysfs_dentry_release(struct dentry *dentry)
{ {
sysfs_put(dentry->d_fsdata); kernfs_put(dentry->d_fsdata);
} }
const struct dentry_operations sysfs_dentry_ops = { const struct dentry_operations sysfs_dentry_ops = {
@ -433,7 +455,8 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
return -EINVAL; return -EINVAL;
sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
sd->s_parent = sysfs_get(parent_sd); sd->s_parent = parent_sd;
kernfs_get(parent_sd);
ret = sysfs_link_sibling(sd); ret = sysfs_link_sibling(sd);
if (ret) if (ret)
@ -553,36 +576,33 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
sysfs_deactivate(sd); sysfs_deactivate(sd);
sysfs_unmap_bin_file(sd); sysfs_unmap_bin_file(sd);
sysfs_put(sd); kernfs_put(sd);
} }
} }
/** /**
* sysfs_find_dirent - find sysfs_dirent with the given name * kernfs_find_ns - find sysfs_dirent with the given name
* @parent_sd: sysfs_dirent to search under * @parent: sysfs_dirent to search under
* @name: name to look for * @name: name to look for
* @ns: the namespace tag to use * @ns: the namespace tag to use
* *
* Look for sysfs_dirent with name @name under @parent_sd. * Look for sysfs_dirent with name @name under @parent. Returns pointer to
* * the found sysfs_dirent on success, %NULL on failure.
* LOCKING:
* mutex_lock(sysfs_mutex)
*
* RETURNS:
* Pointer to sysfs_dirent if found, NULL if not.
*/ */
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent,
const unsigned char *name, const unsigned char *name,
const void *ns) const void *ns)
{ {
struct rb_node *node = parent_sd->s_dir.children.rb_node; struct rb_node *node = parent->s_dir.children.rb_node;
bool has_ns = parent_sd->s_flags & SYSFS_FLAG_NS; bool has_ns = parent->s_flags & SYSFS_FLAG_NS;
unsigned int hash; unsigned int hash;
lockdep_assert_held(&sysfs_mutex);
if (has_ns != (bool)ns) { if (has_ns != (bool)ns) {
WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n",
has_ns ? "required" : "invalid", has_ns ? "required" : "invalid",
parent_sd->s_name, name); parent->s_name, name);
return NULL; return NULL;
} }
@ -604,34 +624,28 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
} }
/** /**
* sysfs_get_dirent_ns - find and get sysfs_dirent with the given name * kernfs_find_and_get_ns - find and get sysfs_dirent with the given name
* @parent_sd: sysfs_dirent to search under * @parent: sysfs_dirent to search under
* @name: name to look for * @name: name to look for
* @ns: the namespace tag to use * @ns: the namespace tag to use
* *
* Look for sysfs_dirent with name @name under @parent_sd and get * Look for sysfs_dirent with name @name under @parent and get a reference
* it if found. * if found. This function may sleep and returns pointer to the found
* * sysfs_dirent on success, %NULL on failure.
* LOCKING:
* Kernel thread context (may sleep). Grabs sysfs_mutex.
*
* RETURNS:
* Pointer to sysfs_dirent if found, NULL if not.
*/ */
struct sysfs_dirent *sysfs_get_dirent_ns(struct sysfs_dirent *parent_sd, struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
const unsigned char *name, const char *name, const void *ns)
const void *ns)
{ {
struct sysfs_dirent *sd; struct sysfs_dirent *sd;
mutex_lock(&sysfs_mutex); mutex_lock(&sysfs_mutex);
sd = sysfs_find_dirent(parent_sd, name, ns); sd = kernfs_find_ns(parent, name, ns);
sysfs_get(sd); kernfs_get(sd);
mutex_unlock(&sysfs_mutex); mutex_unlock(&sysfs_mutex);
return sd; return sd;
} }
EXPORT_SYMBOL_GPL(sysfs_get_dirent_ns); EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
/** /**
* kernfs_create_dir_ns - create a directory * kernfs_create_dir_ns - create a directory
@ -667,7 +681,7 @@ struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
if (!rc) if (!rc)
return sd; return sd;
sysfs_put(sd); kernfs_put(sd);
return ERR_PTR(rc); return ERR_PTR(rc);
} }
@ -716,14 +730,15 @@ static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
if (parent_sd->s_flags & SYSFS_FLAG_NS) if (parent_sd->s_flags & SYSFS_FLAG_NS)
ns = sysfs_info(dir->i_sb)->ns; ns = sysfs_info(dir->i_sb)->ns;
sd = sysfs_find_dirent(parent_sd, dentry->d_name.name, ns); sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns);
/* no such entry */ /* no such entry */
if (!sd) { if (!sd) {
ret = ERR_PTR(-ENOENT); ret = ERR_PTR(-ENOENT);
goto out_unlock; goto out_unlock;
} }
dentry->d_fsdata = sysfs_get(sd); kernfs_get(sd);
dentry->d_fsdata = sd;
/* attach dentry and inode */ /* attach dentry and inode */
inode = sysfs_get_inode(dir->i_sb, sd); inode = sysfs_get_inode(dir->i_sb, sd);
@ -859,7 +874,7 @@ int kernfs_remove_by_name_ns(struct sysfs_dirent *dir_sd, const char *name,
sysfs_addrm_start(&acxt); sysfs_addrm_start(&acxt);
sd = sysfs_find_dirent(dir_sd, name, ns); sd = kernfs_find_ns(dir_sd, name, ns);
if (sd) if (sd)
__kernfs_remove(&acxt, sd); __kernfs_remove(&acxt, sd);
@ -925,7 +940,7 @@ int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
goto out; /* nothing to rename */ goto out; /* nothing to rename */
error = -EEXIST; error = -EEXIST;
if (sysfs_find_dirent(new_parent, new_name, new_ns)) if (kernfs_find_ns(new_parent, new_name, new_ns))
goto out; goto out;
/* rename sysfs_dirent */ /* rename sysfs_dirent */
@ -943,8 +958,8 @@ int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
* Move to the appropriate place in the appropriate directories rbtree. * Move to the appropriate place in the appropriate directories rbtree.
*/ */
sysfs_unlink_sibling(sd); sysfs_unlink_sibling(sd);
sysfs_get(new_parent); kernfs_get(new_parent);
sysfs_put(sd->s_parent); kernfs_put(sd->s_parent);
sd->s_ns = new_ns; sd->s_ns = new_ns;
sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns); sd->s_hash = sysfs_name_hash(sd->s_name, sd->s_ns);
sd->s_parent = new_parent; sd->s_parent = new_parent;
@ -1000,7 +1015,7 @@ static inline unsigned char dt_type(struct sysfs_dirent *sd)
static int sysfs_dir_release(struct inode *inode, struct file *filp) static int sysfs_dir_release(struct inode *inode, struct file *filp)
{ {
sysfs_put(filp->private_data); kernfs_put(filp->private_data);
return 0; return 0;
} }
@ -1011,7 +1026,7 @@ static struct sysfs_dirent *sysfs_dir_pos(const void *ns,
int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) && int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
pos->s_parent == parent_sd && pos->s_parent == parent_sd &&
hash == pos->s_hash; hash == pos->s_hash;
sysfs_put(pos); kernfs_put(pos);
if (!valid) if (!valid)
pos = NULL; pos = NULL;
} }
@ -1075,8 +1090,10 @@ static int sysfs_readdir(struct file *file, struct dir_context *ctx)
unsigned int type = dt_type(pos); unsigned int type = dt_type(pos);
int len = strlen(name); int len = strlen(name);
ino_t ino = pos->s_ino; ino_t ino = pos->s_ino;
ctx->pos = pos->s_hash; ctx->pos = pos->s_hash;
file->private_data = sysfs_get(pos); file->private_data = pos;
kernfs_get(pos);
mutex_unlock(&sysfs_mutex); mutex_unlock(&sysfs_mutex);
if (!dir_emit(ctx, name, len, ino, type)) if (!dir_emit(ctx, name, len, ino, type))

41
fs/sysfs/file.c
View file

@ -881,19 +881,19 @@ void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
struct sysfs_dirent *sd = k->sd, *tmp; struct sysfs_dirent *sd = k->sd, *tmp;
if (sd && dir) if (sd && dir)
sd = sysfs_get_dirent(sd, dir); sd = kernfs_find_and_get(sd, dir);
else else
sysfs_get(sd); kernfs_get(sd);
if (sd && attr) { if (sd && attr) {
tmp = sysfs_get_dirent(sd, attr); tmp = kernfs_find_and_get(sd, attr);
sysfs_put(sd); kernfs_put(sd);
sd = tmp; sd = tmp;
} }
if (sd) { if (sd) {
kernfs_notify(sd); kernfs_notify(sd);
sysfs_put(sd); kernfs_put(sd);
} }
} }
EXPORT_SYMBOL_GPL(sysfs_notify); EXPORT_SYMBOL_GPL(sysfs_notify);
@ -1052,7 +1052,7 @@ struct sysfs_dirent *kernfs_create_file_ns_key(struct sysfs_dirent *parent,
sysfs_addrm_finish(&acxt); sysfs_addrm_finish(&acxt);
if (rc) { if (rc) {
sysfs_put(sd); kernfs_put(sd);
return ERR_PTR(rc); return ERR_PTR(rc);
} }
return sd; return sd;
@ -1106,16 +1106,18 @@ int sysfs_add_file_to_group(struct kobject *kobj,
struct sysfs_dirent *dir_sd; struct sysfs_dirent *dir_sd;
int error; int error;
if (group) if (group) {
dir_sd = sysfs_get_dirent(kobj->sd, group); dir_sd = kernfs_find_and_get(kobj->sd, group);
else } else {
dir_sd = sysfs_get(kobj->sd); dir_sd = kobj->sd;
kernfs_get(dir_sd);
}
if (!dir_sd) if (!dir_sd)
return -ENOENT; return -ENOENT;
error = sysfs_add_file(dir_sd, attr, false); error = sysfs_add_file(dir_sd, attr, false);
sysfs_put(dir_sd); kernfs_put(dir_sd);
return error; return error;
} }
@ -1135,7 +1137,7 @@ int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
struct iattr newattrs; struct iattr newattrs;
int rc; int rc;
sd = sysfs_get_dirent(kobj->sd, attr->name); sd = kernfs_find_and_get(kobj->sd, attr->name);
if (!sd) if (!sd)
return -ENOENT; return -ENOENT;
@ -1144,7 +1146,7 @@ int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
rc = kernfs_setattr(sd, &newattrs); rc = kernfs_setattr(sd, &newattrs);
sysfs_put(sd); kernfs_put(sd);
return rc; return rc;
} }
EXPORT_SYMBOL_GPL(sysfs_chmod_file); EXPORT_SYMBOL_GPL(sysfs_chmod_file);
@ -1185,13 +1187,16 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
{ {
struct sysfs_dirent *dir_sd; struct sysfs_dirent *dir_sd;
if (group) if (group) {
dir_sd = sysfs_get_dirent(kobj->sd, group); dir_sd = kernfs_find_and_get(kobj->sd, group);
else } else {
dir_sd = sysfs_get(kobj->sd); dir_sd = kobj->sd;
kernfs_get(dir_sd);
}
if (dir_sd) { if (dir_sd) {
kernfs_remove_by_name(dir_sd, attr->name); kernfs_remove_by_name(dir_sd, attr->name);
sysfs_put(dir_sd); kernfs_put(dir_sd);
} }
} }
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);

30
fs/sysfs/group.c
View file

@ -108,13 +108,13 @@ static int internal_create_group(struct kobject *kobj, int update,
} }
} else } else
sd = kobj->sd; sd = kobj->sd;
sysfs_get(sd); kernfs_get(sd);
error = create_files(sd, kobj, grp, update); error = create_files(sd, kobj, grp, update);
if (error) { if (error) {
if (grp->name) if (grp->name)
kernfs_remove(sd); kernfs_remove(sd);
} }
sysfs_put(sd); kernfs_put(sd);
return error; return error;
} }
@ -208,21 +208,23 @@ void sysfs_remove_group(struct kobject *kobj,
struct sysfs_dirent *sd; struct sysfs_dirent *sd;
if (grp->name) { if (grp->name) {
sd = sysfs_get_dirent(dir_sd, grp->name); sd = kernfs_find_and_get(dir_sd, grp->name);
if (!sd) { if (!sd) {
WARN(!sd, KERN_WARNING WARN(!sd, KERN_WARNING
"sysfs group %p not found for kobject '%s'\n", "sysfs group %p not found for kobject '%s'\n",
grp, kobject_name(kobj)); grp, kobject_name(kobj));
return; return;
} }
} else } else {
sd = sysfs_get(dir_sd); sd = dir_sd;
kernfs_get(sd);
}
remove_files(sd, kobj, grp); remove_files(sd, kobj, grp);
if (grp->name) if (grp->name)
kernfs_remove(sd); kernfs_remove(sd);
sysfs_put(sd); kernfs_put(sd);
} }
EXPORT_SYMBOL_GPL(sysfs_remove_group); EXPORT_SYMBOL_GPL(sysfs_remove_group);
@ -263,7 +265,7 @@ int sysfs_merge_group(struct kobject *kobj,
struct attribute *const *attr; struct attribute *const *attr;
int i; int i;
dir_sd = sysfs_get_dirent(kobj->sd, grp->name); dir_sd = kernfs_find_and_get(kobj->sd, grp->name);
if (!dir_sd) if (!dir_sd)
return -ENOENT; return -ENOENT;
@ -273,7 +275,7 @@ int sysfs_merge_group(struct kobject *kobj,
while (--i >= 0) while (--i >= 0)
kernfs_remove_by_name(dir_sd, (*--attr)->name); kernfs_remove_by_name(dir_sd, (*--attr)->name);
} }
sysfs_put(dir_sd); kernfs_put(dir_sd);
return error; return error;
} }
@ -290,11 +292,11 @@ void sysfs_unmerge_group(struct kobject *kobj,
struct sysfs_dirent *dir_sd; struct sysfs_dirent *dir_sd;
struct attribute *const *attr; struct attribute *const *attr;
dir_sd = sysfs_get_dirent(kobj->sd, grp->name); dir_sd = kernfs_find_and_get(kobj->sd, grp->name);
if (dir_sd) { if (dir_sd) {
for (attr = grp->attrs; *attr; ++attr) for (attr = grp->attrs; *attr; ++attr)
kernfs_remove_by_name(dir_sd, (*attr)->name); kernfs_remove_by_name(dir_sd, (*attr)->name);
sysfs_put(dir_sd); kernfs_put(dir_sd);
} }
} }
EXPORT_SYMBOL_GPL(sysfs_unmerge_group); EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
@ -312,12 +314,12 @@ int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
struct sysfs_dirent *dir_sd; struct sysfs_dirent *dir_sd;
int error = 0; int error = 0;
dir_sd = sysfs_get_dirent(kobj->sd, group_name); dir_sd = kernfs_find_and_get(kobj->sd, group_name);
if (!dir_sd) if (!dir_sd)
return -ENOENT; return -ENOENT;
error = sysfs_create_link_sd(dir_sd, target, link_name); error = sysfs_create_link_sd(dir_sd, target, link_name);
sysfs_put(dir_sd); kernfs_put(dir_sd);
return error; return error;
} }
@ -334,10 +336,10 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
{ {
struct sysfs_dirent *dir_sd; struct sysfs_dirent *dir_sd;
dir_sd = sysfs_get_dirent(kobj->sd, group_name); dir_sd = kernfs_find_and_get(kobj->sd, group_name);
if (dir_sd) { if (dir_sd) {
kernfs_remove_by_name(dir_sd, link_name); kernfs_remove_by_name(dir_sd, link_name);
sysfs_put(dir_sd); kernfs_put(dir_sd);
} }
} }
EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group); EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);

5
fs/sysfs/inode.c
View file

@ -254,7 +254,8 @@ int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
{ {
inode->i_private = sysfs_get(sd); kernfs_get(sd);
inode->i_private = sd;
inode->i_mapping->a_ops = &sysfs_aops; inode->i_mapping->a_ops = &sysfs_aops;
inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
inode->i_op = &sysfs_inode_operations; inode->i_op = &sysfs_inode_operations;
@ -321,7 +322,7 @@ void sysfs_evict_inode(struct inode *inode)
truncate_inode_pages(&inode->i_data, 0); truncate_inode_pages(&inode->i_data, 0);
clear_inode(inode); clear_inode(inode);
sysfs_put(sd); kernfs_put(sd);
} }
int sysfs_permission(struct inode *inode, int mask) int sysfs_permission(struct inode *inode, int mask)

14
fs/sysfs/mount.c
View file

@ -184,17 +184,3 @@ out_err:
sysfs_dir_cachep = NULL; sysfs_dir_cachep = NULL;
goto out; goto out;
} }
#undef sysfs_get
struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
{
return __sysfs_get(sd);
}
EXPORT_SYMBOL_GPL(sysfs_get);
#undef sysfs_put
void sysfs_put(struct sysfs_dirent *sd)
{
__sysfs_put(sd);
}
EXPORT_SYMBOL_GPL(sysfs_put);

16
fs/sysfs/symlink.c
View file

@ -44,7 +44,7 @@ struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
if (parent->s_flags & SYSFS_FLAG_NS) if (parent->s_flags & SYSFS_FLAG_NS)
sd->s_ns = target->s_ns; sd->s_ns = target->s_ns;
sd->s_symlink.target_sd = target; sd->s_symlink.target_sd = target;
sysfs_get(target); /* ref owned by symlink */ kernfs_get(target); /* ref owned by symlink */
sysfs_addrm_start(&acxt); sysfs_addrm_start(&acxt);
error = sysfs_add_one(&acxt, sd, parent); error = sysfs_add_one(&acxt, sd, parent);
@ -53,7 +53,7 @@ struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
if (!error) if (!error)
return sd; return sd;
sysfs_put(sd); kernfs_put(sd);
return ERR_PTR(error); return ERR_PTR(error);
} }
@ -72,15 +72,17 @@ static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
* sysfs_remove_dir() for details. * sysfs_remove_dir() for details.
*/ */
spin_lock(&sysfs_symlink_target_lock); spin_lock(&sysfs_symlink_target_lock);
if (target->sd) if (target->sd) {
target_sd = sysfs_get(target->sd); target_sd = target->sd;
kernfs_get(target_sd);
}
spin_unlock(&sysfs_symlink_target_lock); spin_unlock(&sysfs_symlink_target_lock);
if (!target_sd) if (!target_sd)
return -ENOENT; return -ENOENT;
sd = kernfs_create_link(parent_sd, name, target_sd); sd = kernfs_create_link(parent_sd, name, target_sd);
sysfs_put(target_sd); kernfs_put(target_sd);
if (!IS_ERR(sd)) if (!IS_ERR(sd))
return 0; return 0;
@ -216,7 +218,7 @@ int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
old_ns = targ->sd->s_ns; old_ns = targ->sd->s_ns;
result = -ENOENT; result = -ENOENT;
sd = sysfs_get_dirent_ns(parent_sd, old, old_ns); sd = kernfs_find_and_get_ns(parent_sd, old, old_ns);
if (!sd) if (!sd)
goto out; goto out;
@ -229,7 +231,7 @@ int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
result = kernfs_rename_ns(sd, parent_sd, new, new_ns); result = kernfs_rename_ns(sd, parent_sd, new, new_ns);
out: out:
sysfs_put(sd); kernfs_put(sd);
return result; return result;
} }
EXPORT_SYMBOL_GPL(sysfs_rename_link_ns); EXPORT_SYMBOL_GPL(sysfs_rename_link_ns);

22
fs/sysfs/sysfs.h
View file

@ -141,30 +141,8 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
struct sysfs_dirent *parent_sd); struct sysfs_dirent *parent_sd);
void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt); void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt);
struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
const unsigned char *name,
const void *ns);
struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type); struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type);
void release_sysfs_dirent(struct sysfs_dirent *sd);
static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd)
{
if (sd) {
WARN_ON(!atomic_read(&sd->s_count));
atomic_inc(&sd->s_count);
}
return sd;
}
#define sysfs_get(sd) __sysfs_get(sd)
static inline void __sysfs_put(struct sysfs_dirent *sd)
{
if (sd && atomic_dec_and_test(&sd->s_count))
release_sysfs_dirent(sd);
}
#define sysfs_put(sd) __sysfs_put(sd)
/* /*
* inode.c * inode.c
*/ */

19
include/linux/kernfs.h
View file

@ -71,6 +71,11 @@ struct kernfs_ops {
#ifdef CONFIG_SYSFS #ifdef CONFIG_SYSFS
struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
const char *name, const void *ns);
void kernfs_get(struct sysfs_dirent *sd);
void kernfs_put(struct sysfs_dirent *sd);
struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
const char *name, void *priv, const char *name, void *priv,
const void *ns); const void *ns);
@ -94,6 +99,14 @@ void kernfs_notify(struct sysfs_dirent *sd);
#else /* CONFIG_SYSFS */ #else /* CONFIG_SYSFS */
static inline struct sysfs_dirent *
kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name,
const void *ns)
{ return NULL; }
static inline void kernfs_get(struct sysfs_dirent *sd) { }
static inline void kernfs_put(struct sysfs_dirent *sd) { }
static inline struct sysfs_dirent * static inline struct sysfs_dirent *
kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv, kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv,
const void *ns) const void *ns)
@ -132,6 +145,12 @@ static inline void kernfs_notify(struct sysfs_dirent *sd) { }
#endif /* CONFIG_SYSFS */ #endif /* CONFIG_SYSFS */
static inline struct sysfs_dirent *
kernfs_find_and_get(struct sysfs_dirent *sd, const char *name)
{
return kernfs_find_and_get_ns(sd, name, NULL);
}
static inline struct sysfs_dirent * static inline struct sysfs_dirent *
kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv) kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv)
{ {

41
include/linux/sysfs.h
View file

@ -243,11 +243,6 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
const char *link_name); const char *link_name);
void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr); void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
struct sysfs_dirent *sysfs_get_dirent_ns(struct sysfs_dirent *parent_sd,
const unsigned char *name,
const void *ns);
struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
void sysfs_put(struct sysfs_dirent *sd);
int __must_check sysfs_init(void); int __must_check sysfs_init(void);
@ -417,19 +412,6 @@ static inline void sysfs_notify(struct kobject *kobj, const char *dir,
const char *attr) const char *attr)
{ {
} }
static inline struct sysfs_dirent *
sysfs_get_dirent_ns(struct sysfs_dirent *parent_sd, const unsigned char *name,
const void *ns)
{
return NULL;
}
static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
{
return NULL;
}
static inline void sysfs_put(struct sysfs_dirent *sd)
{
}
static inline int __must_check sysfs_init(void) static inline int __must_check sysfs_init(void)
{ {
@ -456,15 +438,26 @@ static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target
return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL); return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);
} }
static inline struct sysfs_dirent *
sysfs_get_dirent(struct sysfs_dirent *parent_sd, const unsigned char *name)
{
return sysfs_get_dirent_ns(parent_sd, name, NULL);
}
static inline void sysfs_notify_dirent(struct sysfs_dirent *sd) static inline void sysfs_notify_dirent(struct sysfs_dirent *sd)
{ {
kernfs_notify(sd); kernfs_notify(sd);
} }
static inline struct sysfs_dirent *
sysfs_get_dirent(struct sysfs_dirent *parent_sd, const unsigned char *name)
{
return kernfs_find_and_get(parent_sd, name);
}
static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
{
kernfs_get(sd);
return sd;
}
static inline void sysfs_put(struct sysfs_dirent *sd)
{
kernfs_put(sd);
}
#endif /* _SYSFS_H_ */ #endif /* _SYSFS_H_ */