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Commit 9fc8c5fa authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

debugfs: add debugfs_lookup_and_remove() 



commit dec9b2f1e0455a151a7293c367da22ab973f713e upstream.

There is a very common pattern of using
debugfs_remove(debufs_lookup(..)) which results in a dentry leak of the
dentry that was looked up.  Instead of having to open-code the correct
pattern of calling dput() on the dentry, create
debugfs_lookup_and_remove() to handle this pattern automatically and
properly without any memory leaks.

Cc: stable <stable@kernel.org>
Reported-by: default avatarKuyo Chang <kuyo.chang@mediatek.com>
Tested-by: default avatarKuyo Chang <kuyo.chang@mediatek.com>
Link: https://lore.kernel.org/r/YxIaQ8cSinDR881k@kroah.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0d895d2b

fs/debugfs/inode.c

+22 −0
Original line number Diff line number Diff line
@@ -742,6 +742,28 @@ void debugfs_remove(struct dentry *dentry) 
}

EXPORT_SYMBOL_GPL(debugfs_remove);



/**

 * debugfs_lookup_and_remove - lookup a directory or file and recursively remove it

 * @name: a pointer to a string containing the name of the item to look up.

 * @parent: a pointer to the parent dentry of the item.

 *

 * This is the equlivant of doing something like

 * debugfs_remove(debugfs_lookup(..)) but with the proper reference counting

 * handled for the directory being looked up.

 */

void debugfs_lookup_and_remove(const char *name, struct dentry *parent)

{

	struct dentry *dentry;



	dentry = debugfs_lookup(name, parent);

	if (!dentry)

		return;



	debugfs_remove(dentry);

	dput(dentry);

}

EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove);



/**

 * debugfs_remove_recursive - recursively removes a directory

 * @dentry: a pointer to a the dentry of the directory to be removed.  If this

include/linux/debugfs.h

+6 −0
Original line number Diff line number Diff line
@@ -85,6 +85,8 @@ struct dentry *debugfs_create_automount(const char *name, 
void debugfs_remove(struct dentry *dentry);

void debugfs_remove_recursive(struct dentry *dentry);



void debugfs_lookup_and_remove(const char *name, struct dentry *parent);



const struct file_operations *debugfs_real_fops(const struct file *filp);



int debugfs_file_get(struct dentry *dentry);
@@ -216,6 +218,10 @@ static inline void debugfs_remove(struct dentry *dentry) 
static inline void debugfs_remove_recursive(struct dentry *dentry)

{ }



static inline void debugfs_lookup_and_remove(const char *name,

					     struct dentry *parent)

{ }



const struct file_operations *debugfs_real_fops(const struct file *filp);



static inline int debugfs_file_get(struct dentry *dentry)