sysfs, kernfs: revamp sysfs_dirent active_ref lockdep annotation
Currently, sysfs_dirent active_ref lockdep annotation uses
attribute->[s]key as the lockdep key, which forces
kernfs_create_file_ns() to assume that sysfs_dirent->priv is pointing
to a struct attribute which may not be true for non-sysfs users. This
patch restructures the lockdep annotation such that
* kernfs_ops contains lockdep_key which is used by default for files
created kernfs_create_file_ns().
* kernfs_create_file_ns_key() is introduced which takes an extra @key
argument. The created file will use the specified key for
active_ref lockdep annotation. If NULL is specified, lockdep for
the file is disabled.
* sysfs_add_file_mode_ns() is updated to use
kernfs_create_file_ns_key() with the appropriate key from the
attribute or NULL if ignore_lockdep is set.
This makes the lockdep annotation properly contained in kernfs while
allowing sysfs to cleanly keep its current behavior. This patch
doesn't introduce any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index a68cbef..e4eca28 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -58,7 +58,7 @@
*/
static const struct kernfs_ops *kernfs_ops(struct sysfs_dirent *sd)
{
- if (!sysfs_ignore_lockdep(sd))
+ if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
lockdep_assert_held(sd);
return sd->s_attr.ops;
}
@@ -71,7 +71,7 @@
{
struct kobject *kobj = sd->s_parent->priv;
- if (!sysfs_ignore_lockdep(sd))
+ if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
lockdep_assert_held(sd);
return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
}
@@ -942,6 +942,7 @@
const struct attribute *attr, bool is_bin,
umode_t mode, const void *ns)
{
+ struct lock_class_key *key = NULL;
const struct kernfs_ops *ops;
struct sysfs_dirent *sd;
loff_t size;
@@ -981,8 +982,12 @@
size = battr->size;
}
- sd = kernfs_create_file_ns(dir_sd, attr->name, mode, size,
- ops, (void *)attr, ns);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ if (!attr->ignore_lockdep)
+ key = attr->key ?: (struct lock_class_key *)&attr->skey;
+#endif
+ sd = kernfs_create_file_ns_key(dir_sd, attr->name, mode, size,
+ ops, (void *)attr, ns, key);
if (IS_ERR(sd)) {
if (PTR_ERR(sd) == -EEXIST)
sysfs_warn_dup(dir_sd, attr->name);
@@ -992,7 +997,7 @@
}
/**
- * kernfs_create_file_ns - create a file
+ * kernfs_create_file_ns_key - create a file
* @parent: directory to create the file in
* @name: name of the file
* @mode: mode of the file
@@ -1000,14 +1005,16 @@
* @ops: kernfs operations for the file
* @priv: private data for the file
* @ns: optional namespace tag of the file
+ * @key: lockdep key for the file's active_ref, %NULL to disable lockdep
*
* Returns the created node on success, ERR_PTR() value on error.
*/
-struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
- const char *name,
- umode_t mode, loff_t size,
- const struct kernfs_ops *ops,
- void *priv, const void *ns)
+struct sysfs_dirent *kernfs_create_file_ns_key(struct sysfs_dirent *parent,
+ const char *name,
+ umode_t mode, loff_t size,
+ const struct kernfs_ops *ops,
+ void *priv, const void *ns,
+ struct lock_class_key *key)
{
struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
@@ -1022,7 +1029,13 @@
sd->s_attr.size = size;
sd->s_ns = ns;
sd->priv = priv;
- sysfs_dirent_init_lockdep(sd);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ if (key) {
+ lockdep_init_map(&sd->dep_map, "s_active", key, 0);
+ sd->s_flags |= SYSFS_FLAG_LOCKDEP;
+ }
+#endif
/*
* sd->s_attr.ops is accesible only while holding active ref. We
