lkml.org 
[lkml]   [2012]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v2] compiler.h: Include <linux/bug.h> to avoid build breakage with ARRAY_SIZE()
On 12-04-04 10:29 AM, Uwe Kleine-König wrote:
> Hello,
>
> On Fri, Mar 02, 2012 at 09:22:02AM -0500, Paul Gortmaker wrote:
>> On 12-03-01 10:13 PM, Fabio Estevam wrote:
>>> On Thu, Mar 1, 2012 at 11:49 PM, Paul Gortmaker
>>> <paul.gortmaker@windriver.com> wrote:
>>>
>>>> Thanks, but no.
>>>>
>>>> You missed the whole point of my previous comments -- that being
>>>> that we don't want to just jam headers into always-used headers.
>>>
>>> Yes, it is not clear for me how to fix this build error. I got
>>> different feedbacks from you, Russell and Sam.
>>
>> Understood, there was some discussion there. Anyways it is already
>> dealt with in yesterday's linux-next tree, so you won't have the
>> build failure anymore.
> I hit that same problem in an not yet mainlined source file. A simple
> file containing only:

A quick check shows about 15000 instances in mainline. Even if 1% of
those were blowing up, I'd expect a full mailbox.

>
> #include <linux/kernel.h>
>
> int array[3];
>
> int func(void)
> {
> return ARRAY_SIZE(array);

Well, ARRAY_SIZE is just a convenient macro that uses BUG content.
Hiding it behind a name doesn't change the fact that you've
implicitly decided to use bug.h content. Maybe you really don't
want to be using it. Maybe we should have:

--------------------------------------
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -43,6 +43,7 @@
#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)

+#define __ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))

/*
------------------------------------
and give people a choice?

Don't get me wrong. I'm not all extremist about this. If it turns
out that it seems to cause way too much grief, and someone like Andrew
says "Yeah, lets put #include <linux/bug.h> back in kernel.h" then I
won't hesitate to do that. But given that code currently in mainline
isn't blowing up all over, I wasn't yet convinced we needed to do that.

Paul.

> }
>
> fails to build on top of v3.4-rc1. Am I right that you saying "you won't
> have the build failure anymore" means that each of these is now needed
> to be fixed individually by adding
>
> #include <linux/bug.h>
>
> ? Otherwise it's not fixed for me.
>
> Thanks
> Uwe
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2012-04-05 20:39    [W:0.099 / U:0.840 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site