[PATCH 33/34] sysfs, kernfs: implement kernfs_ns_enabled()

Tejun Heo
2013-11-28T19:56:51Z

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.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
fs/kernfs/dir.c | 10 +++++-----
fs/kernfs/symlink.c | 2 +-
fs/sysfs/symlink.c | 2 +-
include/linux/kernfs.h | 11 +++++++++++
4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 7c5b517..f51e062 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -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);
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 004c164..12569a7 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -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 */
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 62f0e01..1b8c9ed 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -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);
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index f3f873e..7cb636c 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -188,6 +188,17 @@ 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;
+}
+
#ifdef CONFIG_SYSFS

struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent,
--
1.8.4.2