From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752283AbcCGIP3 (ORCPT ); Mon, 7 Mar 2016 03:15:29 -0500 Received: from szxga05-in.huawei.com ([58.251.152.179]:58652 "EHLO szxga05-in.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751958AbcCGIPV (ORCPT ); Mon, 7 Mar 2016 03:15:21 -0500 X-Greylist: delayed 413 seconds by postgrey-1.27 at vger.kernel.org; Mon, 07 Mar 2016 03:15:19 EST From: Yao Dongdong To: , , CC: , Subject: [PATCH] documentation: Make sample code and documentation consistent Date: Mon, 7 Mar 2016 16:02:14 +0800 Message-ID: <1457337734-8341-1-git-send-email-yaodongdong@huawei.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.189] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090201.56DD36F5.0124,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 0e1b168da8650a8aaf05de50a59457ec Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the chapter 'analogy with reader-writer locking', the sample code uses spinlock_t in reader-writer case. Just correct it so that we can read the document easily. Signed-off-by: Yao Dongdong --- Documentation/RCU/whatisRCU.txt | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt index dc49c67..e33304e 100644 --- a/Documentation/RCU/whatisRCU.txt +++ b/Documentation/RCU/whatisRCU.txt @@ -681,22 +681,30 @@ Although RCU can be used in many different ways, a very common use of RCU is analogous to reader-writer locking. The following unified diff shows how closely related RCU and reader-writer locking can be. + @@ -5,5 +5,5 @@ struct el { + int data; + /* Other data fields */ + }; + -rwlock_t listmutex; + +spinlock_t listmutex; + struct el head; + @@ -13,15 +14,15 @@ struct list_head *lp; struct el *p; - - read_lock(); + - read_lock(&listmutex); - list_for_each_entry(p, head, lp) { + rcu_read_lock(); + list_for_each_entry_rcu(p, head, lp) { if (p->key == key) { *result = p->data; - - read_unlock(); + - read_unlock(&listmutex); + rcu_read_unlock(); return 1; } } - - read_unlock(); + - read_unlock(&listmutex); + rcu_read_unlock(); return 0; } @@ -732,7 +740,7 @@ Or, for those who prefer a side-by-side listing: 5 int data; 5 int data; 6 /* Other data fields */ 6 /* Other data fields */ 7 }; 7 }; - 8 spinlock_t listmutex; 8 spinlock_t listmutex; + 8 rwlock_t listmutex; 8 spinlock_t listmutex; 9 struct el head; 9 struct el head; 1 int search(long key, int *result) 1 int search(long key, int *result) @@ -740,15 +748,15 @@ Or, for those who prefer a side-by-side listing: 3 struct list_head *lp; 3 struct list_head *lp; 4 struct el *p; 4 struct el *p; 5 5 - 6 read_lock(); 6 rcu_read_lock(); + 6 read_lock(&listmutex); 6 rcu_read_lock(); 7 list_for_each_entry(p, head, lp) { 7 list_for_each_entry_rcu(p, head, lp) { 8 if (p->key == key) { 8 if (p->key == key) { 9 *result = p->data; 9 *result = p->data; -10 read_unlock(); 10 rcu_read_unlock(); +10 read_unlock(&listmutex); 10 rcu_read_unlock(); 11 return 1; 11 return 1; 12 } 12 } 13 } 13 } -14 read_unlock(); 14 rcu_read_unlock(); +14 read_unlock(&listmutex); 14 rcu_read_unlock(); 15 return 0; 15 return 0; 16 } 16 } -- 1.7.9.5