From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D4A89C433EF for ; Wed, 8 Sep 2021 14:29:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBB2060E94 for ; Wed, 8 Sep 2021 14:29:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351932AbhIHOaW (ORCPT ); Wed, 8 Sep 2021 10:30:22 -0400 Received: from hurricane.elijah.cs.cmu.edu ([128.2.209.191]:41492 "EHLO hurricane.elijah.cs.cmu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351926AbhIHOaV (ORCPT ); Wed, 8 Sep 2021 10:30:21 -0400 Received: from jaharkes by hurricane.elijah.cs.cmu.edu with local (Exim 4.92) (envelope-from ) id 1mNyAP-0004rd-0W; Wed, 08 Sep 2021 10:03:09 -0400 From: Jan Harkes To: Andrew Morton Cc: Jan Harkes , linux-fsdevel@vger.kernel.org, Xiyu Yang , Xin Tan Subject: [PATCH 7/9] coda: Convert from atomic_t to refcount_t on coda_vm_ops->refcnt Date: Wed, 8 Sep 2021 10:03:06 -0400 Message-Id: <20210908140308.18491-8-jaharkes@cs.cmu.edu> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210908140308.18491-1-jaharkes@cs.cmu.edu> References: <20210908140308.18491-1-jaharkes@cs.cmu.edu> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Xiyu Yang refcount_t type and corresponding API can protect refcounters from accidental underflow and overflow and further use-after-free situations. Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: Jan Harkes --- fs/coda/file.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/coda/file.c b/fs/coda/file.c index 52deab784667..29dd87be2fb8 100644 --- a/fs/coda/file.c +++ b/fs/coda/file.c @@ -8,6 +8,7 @@ * to the Coda project. Contact Peter Braam . */ +#include #include #include #include @@ -28,7 +29,7 @@ #include "coda_int.h" struct coda_vm_ops { - atomic_t refcnt; + refcount_t refcnt; struct file *coda_file; const struct vm_operations_struct *host_vm_ops; struct vm_operations_struct vm_ops; @@ -98,7 +99,7 @@ coda_vm_open(struct vm_area_struct *vma) struct coda_vm_ops *cvm_ops = container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); - atomic_inc(&cvm_ops->refcnt); + refcount_inc(&cvm_ops->refcnt); if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open) cvm_ops->host_vm_ops->open(vma); @@ -113,7 +114,7 @@ coda_vm_close(struct vm_area_struct *vma) if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close) cvm_ops->host_vm_ops->close(vma); - if (atomic_dec_and_test(&cvm_ops->refcnt)) { + if (refcount_dec_and_test(&cvm_ops->refcnt)) { vma->vm_ops = cvm_ops->host_vm_ops; fput(cvm_ops->coda_file); kfree(cvm_ops); @@ -189,7 +190,7 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) cvm_ops->vm_ops.open = coda_vm_open; cvm_ops->vm_ops.close = coda_vm_close; cvm_ops->coda_file = coda_file; - atomic_set(&cvm_ops->refcnt, 1); + refcount_set(&cvm_ops->refcnt, 1); vma->vm_ops = &cvm_ops->vm_ops; } -- 2.25.1