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Subject: Re: [PATCH] backports: remove obsolete linux/bitops.h header
From: Johannes Berg <johannes@sipsolutions.net>
To: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Stefan Assmann <sassmann@kpanic.de>, mcgrof@kernel.org,
	backports@vger.kernel.org
Date: Wed, 20 Nov 2013 09:20:17 +0100
In-Reply-To: <528BEB63.3080600@hauke-m.de> (sfid-20131119_235133_050957_98574914)
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	 <528BEB63.3080600@hauke-m.de> (sfid-20131119_235133_050957_98574914)
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On Tue, 2013-11-19 at 23:51 +0100, Hauke Mehrtens wrote:
> On 11/18/2013 03:26 PM, Stefan Assmann wrote:
> > The header seems to be obsolete. Removing it and running devel/ckmake didn't
> > reveal any errors. Missing parts can always be re-added in the new
> > include_next fashion if necessary.
> > 
> > Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
> 
> Some of these functions are needed, because they are not provided by old
> kernel versions.

Overall the idea seems right though - we should have something like

#ifndef __BACKPORT_BITOPS_H
#define __BACKPORT_BITOPS_H
#include_next <linux/bitops.h>

#ifndef for_each_set_bit
#define for_each_set_bit(...) \
	...
#endif

#if kernel_version < 2.6.38
static inline __s32 sign_extend32(...) { ... }
#endif

etc.

#endif /* __BACKPORT_BITOPS_H */

I think.

johannes