debugfs: add debugfs_lookup_and_remove()

stable inclusion
from stable-v4.19.258
commit ebfb744bb6036485dac2a45c46e82b911c3726d1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5UQH4


CVE: NA

--------------------------------

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: Kuyo Chang <kuyo.chang@mediatek.com>
Tested-by: Kuyo Chang <kuyo.chang@mediatek.com>
Link: https://lore.kernel.org/r/YxIaQ8cSinDR881k@kroah.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>