From: Joe Perches <joe@perches.com>
To: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
linux-metag@vger.kernel.org
Subject: Re: [RFC PATCH -next] Fix printk_once build errors due to __read_mostly
Date: Wed, 30 Oct 2013 10:02:02 -0700 [thread overview]
Message-ID: <1383152522.9435.29.camel@joe-AO722> (raw)
In-Reply-To: <1383128301-20231-1-git-send-email-james.hogan@imgtec.com>
On Wed, 2013-10-30 at 10:18 +0000, James Hogan wrote:
> Commit 3e39c1ab04ba (printk: mark printk_once test variable
> __read_mostly) added __read_mostly to the __print_once bool in the
> printk_once() macro, but __read_mostly is defined in <linux/cache.h>
> which isn't included from <linux/printk.h>. This results in build errors
> like this:
>
> arch/metag/mm/l2cache.c: In function 'meta_l2c_setup':
> arch/metag/mm/l2cache.c:56: error: '__read_mostly' undeclared
>
> This is fixed by adding an include of <linux/cache.h> from
> <linux/printk.h> since I don't think printk_once() users should need to
> include <linux/cache.h> for it to work.
>
> Note that this actually adds a recursive include, since <linux/cache.h>
> includes <linux/kernel.h>, which includes <linux/printk.h>. The actual
> dependencies are all in macros so it doesn't actually seem to result in
> any build failures, but it's clearly less than ideal.
[]
> I'm not too keen on this due to the recursive include. Is it better to
> just workaround the problem by including <linux/cache.h> from the .c
> file that fails to build, or should the original patch be removed
> instead?
Maybe also using this would help avoid some of the
circular dependency:
---
include/linux/cache.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/cache.h b/include/linux/cache.h
index 4c57065..17e7e82 100644
--- a/include/linux/cache.h
+++ b/include/linux/cache.h
@@ -1,11 +1,11 @@
#ifndef __LINUX_CACHE_H
#define __LINUX_CACHE_H
-#include <linux/kernel.h>
+#include <uapi/linux/kernel.h>
#include <asm/cache.h>
#ifndef L1_CACHE_ALIGN
-#define L1_CACHE_ALIGN(x) ALIGN(x, L1_CACHE_BYTES)
+#define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES)
#endif
#ifndef SMP_CACHE_BYTES
next prev parent reply other threads:[~2013-10-30 17:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-30 10:18 [RFC PATCH -next] Fix printk_once build errors due to __read_mostly James Hogan
2013-10-30 13:46 ` Joe Perches
2013-10-30 17:02 ` Joe Perches [this message]
2013-10-30 20:48 ` Andrew Morton
2013-10-30 22:58 ` Joe Perches
2013-10-30 23:01 ` [PATCH V2] printk/cache: Mark printk_once test variable __read_mostly Joe Perches
2013-10-31 13:35 ` James Hogan
2013-10-30 23:18 ` [RFC PATCH -next] Fix printk_once build errors due to __read_mostly Stephen Rothwell
2013-10-31 18:29 ` [PATCH V3] printk/cache: Mark printk_once test variable __read_mostly Joe Perches
2013-11-13 0:23 ` Tony Luck
2013-11-13 0:29 ` Joe Perches
2013-11-13 19:31 ` Tony Luck
[not found] ` <CA+8MBbJKN174=ybMNE7Z+oT7KjNBzgdy9cvhb_kACvXAbTo9XA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-11-14 1:16 ` Joe Perches
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