[PATCH 1/2] atomic_ops.rst: Fix wrong example code

[PATCH 1/2] atomic_ops.rst: Fix wrong example code

[SeongJae Park]

Example code snippets for necessary of READ_ONCE() and WRITE_ONCE() has
an unnecessary line of code and wrong condition.  This commit fixes
them.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
---
 Documentation/core-api/atomic_ops.rst | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Documentation/core-api/atomic_ops.rst b/Documentation/core-api/atomic_ops.rst
index fce929144ccd..4ea4af71e68a 100644
--- a/Documentation/core-api/atomic_ops.rst
+++ b/Documentation/core-api/atomic_ops.rst
@@ -111,7 +111,6 @@ If the compiler can prove that do_something() does not store to the
 variable a, then the compiler is within its rights transforming this to
 the following::
 
-	tmp = a;
 	if (a > 0)
 		for (;;)
 			do_something();
@@ -119,7 +118,7 @@ the following::
 If you don't want the compiler to do this (and you probably don't), then
 you should use something like the following::
 
-	while (READ_ONCE(a) < 0)
+	while (READ_ONCE(a) > 0)
 		do_something();
 
 Alternatively, you could place a barrier() call in the loop.
-- 
2.13.0

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[PATCH 2/2] atomic_ops.rst: Use `warning` rst directive

[SeongJae Park]

One warning message in 'atomic_ops.rst' is not using 'warning' rst
directive while others does.  This commit modifies the message to use
'warning' rst directive.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
---
 Documentation/core-api/atomic_ops.rst | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/core-api/atomic_ops.rst b/Documentation/core-api/atomic_ops.rst
index 4ea4af71e68a..2e7165f86f55 100644
--- a/Documentation/core-api/atomic_ops.rst
+++ b/Documentation/core-api/atomic_ops.rst
@@ -466,10 +466,12 @@ Like the above, except that these routines return a boolean which
 indicates whether the changed bit was set _BEFORE_ the atomic bit
 operation.
 
-WARNING! It is incredibly important that the value be a boolean,
-ie. "0" or "1".  Do not try to be fancy and save a few instructions by
-declaring the above to return "long" and just returning something like
-"old_val & mask" because that will not work.
+
+.. warning::
+        It is incredibly important that the value be a boolean, ie. "0" or "1".
+        Do not try to be fancy and save a few instructions by declaring the
+        above to return "long" and just returning something like "old_val &
+        mask" because that will not work.
 
 For one thing, this return value gets truncated to int in many code
 paths using these interfaces, so on 64-bit if the bit is set in the
-- 
2.13.0

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Re: [PATCH 1/2] atomic_ops.rst: Fix wrong example code

[Paul E. McKenney]

On Thu, Apr 19, 2018 at 05:42:44PM +0900, SeongJae Park wrote:
> Example code snippets for necessary of READ_ONCE() and WRITE_ONCE() has
> an unnecessary line of code and wrong condition.  This commit fixes
> them.
> 
> Signed-off-by: SeongJae Park <sj38.park@gmail.com>

Good catch!!!  I queued and pushed both patches for further review,
thank you!

						Thanx, Paul

> ---
>  Documentation/core-api/atomic_ops.rst | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/Documentation/core-api/atomic_ops.rst b/Documentation/core-api/atomic_ops.rst
> index fce929144ccd..4ea4af71e68a 100644
> --- a/Documentation/core-api/atomic_ops.rst
> +++ b/Documentation/core-api/atomic_ops.rst
> @@ -111,7 +111,6 @@ If the compiler can prove that do_something() does not store to the
>  variable a, then the compiler is within its rights transforming this to
>  the following::
> 
> -	tmp = a;
>  	if (a > 0)
>  		for (;;)
>  			do_something();
> @@ -119,7 +118,7 @@ the following::
>  If you don't want the compiler to do this (and you probably don't), then
>  you should use something like the following::
> 
> -	while (READ_ONCE(a) < 0)
> +	while (READ_ONCE(a) > 0)
>  		do_something();
> 
>  Alternatively, you could place a barrier() call in the loop.
> -- 
> 2.13.0
> 

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