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

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

fs/kernfs/dir.c

+23 −0
Original line number Diff line number Diff line
@@ -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

include/linux/kernfs.h

+4 −0
Original line number Diff line number Diff line
@@ -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; }