Commit 9acee9c5 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe

kernfs: implement kernfs_path_len()

Add a function to determine the path length of a kernfs node.  This
for now will be used by writeback tracepoint updates.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 60292bcc
......@@ -91,6 +91,29 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
return ret;
}
/**
* kernfs_path_len - determine the length of the full path of a given node
* @kn: kernfs_node of interest
*
* The returned length doesn't include the space for the terminating '\0'.
*/
size_t kernfs_path_len(struct kernfs_node *kn)
{
size_t len = 0;
unsigned long flags;
spin_lock_irqsave(&kernfs_rename_lock, flags);
do {
len += strlen(kn->name) + 1;
kn = kn->parent;
} while (kn && kn->parent);
spin_unlock_irqrestore(&kernfs_rename_lock, flags);
return len;
}
/**
* kernfs_path - build full path of a given node
* @kn: kernfs_node of interest
......
......@@ -266,6 +266,7 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
}
int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
size_t kernfs_path_len(struct kernfs_node *kn);
char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
size_t buflen);
void pr_cont_kernfs_name(struct kernfs_node *kn);
......@@ -332,6 +333,9 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
{ return -ENOSYS; }
static inline size_t kernfs_path_len(struct kernfs_node *kn)
{ return 0; }
static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
size_t buflen)
{ return NULL; }
......
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