To: David Miller <davem@davemloft.net>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, openib-general@openib.org,
       tom@opengridcomputing.com
Subject: Re: [PATCH] Avoid truncating to 'long' in ALIGN() macro
References: <adazmag5bk1.fsf@cisco.com>
	<20061124.220746.57445336.davem@davemloft.net>
From: Roland Dreier <rdreier@cisco.com>
Date: Sat, 25 Nov 2006 14:56:22 -0800
In-Reply-To: <20061124.220746.57445336.davem@davemloft.net> (David Miller's message of "Fri, 24 Nov 2006 22:07:46 -0800 (PST)")
Message-ID: <adaodqv5e5l.fsf@cisco.com>
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 > Perhaps a better way to fix this is to use
 > typeof() like other similar macros do.

I tried doing

#define ALIGN(x,a)				\
	({					\
		typeof(x) _a = (a);		\
		((x) + _a - 1) & ~(_a - 1);	\
	})

but that won't compile because of <net/neighbour.h>:

	unsigned char		ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];

gcc says:

/scratch/Ksrc/linux-merge/include/net/neighbour.h:104: error: braced-group within expression allowed only inside a function

I guess that could be fixed by changing that declaration but now this
is starting to feel like early 2.6.20 material.

 - R.
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