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Diffstat (limited to 'fs/sysfs/dir.c')
-rw-r--r--fs/sysfs/dir.c37
1 files changed, 28 insertions, 9 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 35a36d39fa2c..e6bb9b2a4cbe 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -132,6 +132,24 @@ static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
}
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
+/* Test for attributes that want to ignore lockdep for read-locking */
+static bool ignore_lockdep(struct sysfs_dirent *sd)
+{
+ return sysfs_type(sd) == SYSFS_KOBJ_ATTR &&
+ sd->s_attr.attr->ignore_lockdep;
+}
+
+#else
+
+static inline bool ignore_lockdep(struct sysfs_dirent *sd)
+{
+ return true;
+}
+
+#endif
+
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
@@ -155,15 +173,17 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
return NULL;
t = atomic_cmpxchg(&sd->s_active, v, v + 1);
- if (likely(t == v)) {
- rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
- return sd;
- }
+ if (likely(t == v))
+ break;
if (t < 0)
return NULL;
cpu_relax();
}
+
+ if (likely(!ignore_lockdep(sd)))
+ rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
+ return sd;
}
/**
@@ -180,7 +200,8 @@ void sysfs_put_active(struct sysfs_dirent *sd)
if (unlikely(!sd))
return;
- rwsem_release(&sd->dep_map, 1, _RET_IP_);
+ if (likely(!ignore_lockdep(sd)))
+ rwsem_release(&sd->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&sd->s_active);
if (likely(v != SD_DEACTIVATED_BIAS))
return;
@@ -858,7 +879,6 @@ int sysfs_rename(struct sysfs_dirent *sd,
struct sysfs_dirent *new_parent_sd, const void *new_ns,
const char *new_name)
{
- const char *dup_name = NULL;
int error;
mutex_lock(&sysfs_mutex);
@@ -875,11 +895,11 @@ int sysfs_rename(struct sysfs_dirent *sd,
/* rename sysfs_dirent */
if (strcmp(sd->s_name, new_name) != 0) {
error = -ENOMEM;
- new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
+ new_name = kstrdup(new_name, GFP_KERNEL);
if (!new_name)
goto out;
- dup_name = sd->s_name;
+ kfree(sd->s_name);
sd->s_name = new_name;
}
@@ -895,7 +915,6 @@ int sysfs_rename(struct sysfs_dirent *sd,
error = 0;
out:
mutex_unlock(&sysfs_mutex);
- kfree(dup_name);
return error;
}