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sysfs, kernfs: implement kernfs_ns_enabled()

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fs/sysfs/symlink.c::sysfs_delete_link() tests @sd->s_flags for
SYSFS_FLAG_NS.  Let's add kernfs_ns_enabled() so that sysfs doesn't
have to test sysfs_dirent flag directly.  This makes things tidier for
kernfs proper too.

This is purely cosmetic.

v2: To avoid possible NULL deref, use noop dummy implementation which
    always returns false when !CONFIG_SYSFS.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tejun Heo 2013-11-29 17:19:09 -05:00 committed by Greg Kroah-Hartman
parent cf9e5a73aa
commit ac9bba0310
4 changed files with 21 additions and 7 deletions
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10
fs/kernfs/dir.c
View File

@ -291,7 +291,7 @@ static int sysfs_dentry_revalidate(struct dentry *dentry, unsigned int flags)
goto out_bad;
/* The sysfs dirent has been moved to a different namespace */
if (sd->s_parent && (sd->s_parent->s_flags & SYSFS_FLAG_NS) &&
if (sd->s_parent && kernfs_ns_enabled(sd->s_parent) &&
sysfs_info(dentry->d_sb)->ns != sd->s_ns)
goto out_bad;
@ -414,7 +414,7 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt)
int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd,
struct sysfs_dirent *parent_sd)
{
bool has_ns = parent_sd->s_flags & SYSFS_FLAG_NS;
bool has_ns = kernfs_ns_enabled(parent_sd);
struct sysfs_inode_attrs *ps_iattr;
int ret;
@ -535,7 +535,7 @@ static struct sysfs_dirent *kernfs_find_ns(struct sysfs_dirent *parent,
const void *ns)
{
struct rb_node *node = parent->s_dir.children.rb_node;
bool has_ns = parent->s_flags & SYSFS_FLAG_NS;
bool has_ns = kernfs_ns_enabled(parent);
unsigned int hash;
lockdep_assert_held(&sysfs_mutex);
@ -685,7 +685,7 @@ static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
mutex_lock(&sysfs_mutex);
if (parent_sd->s_flags & SYSFS_FLAG_NS)
if (kernfs_ns_enabled(parent_sd))
ns = sysfs_info(dir->i_sb)->ns;
sd = kernfs_find_ns(parent_sd, dentry->d_name.name, ns);
@ -968,7 +968,7 @@ static int sysfs_readdir(struct file *file, struct dir_context *ctx)
return 0;
mutex_lock(&sysfs_mutex);
if (parent_sd->s_flags & SYSFS_FLAG_NS)
if (kernfs_ns_enabled(parent_sd))
ns = sysfs_info(dentry->d_sb)->ns;
for (pos = sysfs_dir_pos(ns, parent_sd, ctx->pos, pos);

2
fs/kernfs/symlink.c
View File

@ -35,7 +35,7 @@ struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
if (!sd)
return ERR_PTR(-ENOMEM);
if (parent->s_flags & SYSFS_FLAG_NS)
if (kernfs_ns_enabled(parent))
sd->s_ns = target->s_ns;
sd->s_symlink.target_sd = target;
kernfs_get(target); /* ref owned by symlink */

2
fs/sysfs/symlink.c
View File

@ -128,7 +128,7 @@ void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
* sysfs_remove_dir() for details.
*/
spin_lock(&sysfs_symlink_target_lock);
if (targ->sd && (kobj->sd->s_flags & SYSFS_FLAG_NS))
if (targ->sd && kernfs_ns_enabled(kobj->sd))
ns = targ->sd->s_ns;
spin_unlock(&sysfs_symlink_target_lock);
kernfs_remove_by_name_ns(kobj->sd, name, ns);

14
include/linux/kernfs.h
View File

@ -190,6 +190,17 @@ static inline void kernfs_enable_ns(struct sysfs_dirent *sd)
sd->s_flags |= SYSFS_FLAG_NS;
}
/**
* kernfs_ns_enabled - test whether namespace is enabled
* @sd: the node to test
*
* Test whether namespace filtering is enabled for the children of @ns.
*/
static inline bool kernfs_ns_enabled(struct sysfs_dirent *sd)
{
return sd->s_flags & SYSFS_FLAG_NS;
}
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);
@ -232,6 +243,9 @@ static inline enum kernfs_node_type sysfs_type(struct sysfs_dirent *sd)
static inline void kernfs_enable_ns(struct sysfs_dirent *sd) { }
static inline bool kernfs_ns_enabled(struct sysfs_dirent *sd)
{ return false; }
static inline struct sysfs_dirent *
kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name,
const void *ns)