* [PATCH] documentation: Make sample code and documentation consistent
@ 2016-03-07 8:02 Yao Dongdong
2016-03-07 19:58 ` Paul E. McKenney
0 siblings, 1 reply; 2+ messages in thread
From: Yao Dongdong @ 2016-03-07 8:02 UTC (permalink / raw)
To: paulmck, josh, corbet; +Cc: linux-kernel, linux-doc
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 <yaodongdong@huawei.com>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] documentation: Make sample code and documentation consistent
2016-03-07 8:02 [PATCH] documentation: Make sample code and documentation consistent Yao Dongdong
@ 2016-03-07 19:58 ` Paul E. McKenney
0 siblings, 0 replies; 2+ messages in thread
From: Paul E. McKenney @ 2016-03-07 19:58 UTC (permalink / raw)
To: Yao Dongdong; +Cc: josh, corbet, linux-kernel, linux-doc
On Mon, Mar 07, 2016 at 04:02:14PM +0800, Yao Dongdong wrote:
> 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 <yaodongdong@huawei.com>
Good catch, queued for review.
Thanx, Paul
> ---
> 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
>
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