From patchwork Mon Dec 3 00:30:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 10708471 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ACF4913BB for ; Mon, 3 Dec 2018 00:32:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9B4AA2A51E for ; Mon, 3 Dec 2018 00:32:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8CE6F2A54D; Mon, 3 Dec 2018 00:32:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2CBDF2A51E for ; Mon, 3 Dec 2018 00:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725938AbeLCAc1 (ORCPT ); Sun, 2 Dec 2018 19:32:27 -0500 Received: from mx2.suse.de ([195.135.220.15]:40932 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725785AbeLCAc1 (ORCPT ); Sun, 2 Dec 2018 19:32:27 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 9BC41ADC0; Mon, 3 Dec 2018 00:32:21 +0000 (UTC) From: NeilBrown To: "J. Bruce Fields" , Chuck Lever , Jeff Layton , Trond Myklebust , Anna Schumaker Date: Mon, 03 Dec 2018 11:30:30 +1100 Subject: [PATCH 04/23] cred: allow get_cred() and put_cred() to be given NULL. Cc: Linux NFS Mailing List , linux-kernel@vger.kernel.org Message-ID: <154379703020.28598.1657780881720707861.stgit@noble> In-Reply-To: <154379689752.28598.6750646657534626618.stgit@noble> References: <154379689752.28598.6750646657534626618.stgit@noble> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It is common practice for helpers like this to silently, accept a NULL pointer. get_rpccred() and put_rpccred() used by NFS act this way and using the same interface will ease the conversion for NFS, and simplify the resulting code. Signed-off-by: NeilBrown --- include/linux/cred.h | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/include/linux/cred.h b/include/linux/cred.h index 48979fcb95cf..4907c9df86b3 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -237,7 +237,7 @@ static inline struct cred *get_new_cred(struct cred *cred) * @cred: The credentials to reference * * Get a reference on the specified set of credentials. The caller must - * release the reference. + * release the reference. If %NULL is passed, it is returned with no action. * * This is used to deal with a committed set of credentials. Although the * pointer is const, this will temporarily discard the const and increment the @@ -248,6 +248,8 @@ static inline struct cred *get_new_cred(struct cred *cred) static inline const struct cred *get_cred(const struct cred *cred) { struct cred *nonconst_cred = (struct cred *) cred; + if (!cred) + return cred; validate_creds(cred); return get_new_cred(nonconst_cred); } @@ -268,7 +270,7 @@ static inline const struct cred *get_cred_rcu(const struct cred *cred) * @cred: The credentials to release * * Release a reference to a set of credentials, deleting them when the last ref - * is released. + * is released. If %NULL is passed, nothing is done. * * This takes a const pointer to a set of credentials because the credentials * on task_struct are attached by const pointers to prevent accidental @@ -278,9 +280,11 @@ static inline void put_cred(const struct cred *_cred) { struct cred *cred = (struct cred *) _cred; - validate_creds(cred); - if (atomic_dec_and_test(&(cred)->usage)) - __put_cred(cred); + if (cred) { + validate_creds(cred); + if (atomic_dec_and_test(&(cred)->usage)) + __put_cred(cred); + } } /**