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Message-Id: <20170329143656.d89a2f139316df3f39a91db9@linux-foundation.org>
Date: Wed, 29 Mar 2017 14:36:56 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: Niklas Söderlund
<niklas.soderlund+renesas@...natech.se>,
Jessica Yu <jeyu@...hat.com>,
Johannes Berg <johannes.berg@...el.com>,
Petr Mladek <pmladek@...e.com>,
Larry Finger <Larry.Finger@...inger.net>,
linux-kernel@...r.kernel.org,
Gustavo Padovan <gustavo.padovan@...labora.co.uk>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Peter Zijlstra <peterz@...radead.org>,
Luis de Bethencourt <luisbg@....samsung.com>,
Josh Triplett <josh@...htriplett.org>
Subject: Re: [PATCH] kernel.h: add IS_PTR_ALIGNED() macro
On Wed, 29 Mar 2017 19:22:10 +0900 Masahiro Yamada <yamada.masahiro@...ionext.com> wrote:
> We often check if a pointer has a specific alignment. Because the
> '&' (bitwise AND) operator cannot take a pointer for the operand,
> so we need a cast like, IS_ALIGNED((unsigned long)p, a).
>
> IS_PTR_ALIGNED will be useful as a shorthand.
>
> ...
>
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -50,6 +50,7 @@
> #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
> #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
> #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
> +#define IS_PTR_ALIGNED(p, a) (IS_ALIGNED((unsigned long)p, a))
>
> /* generic data direction definitions */
> #define READ 0
It would be nice to see some conversions which actually use this new
macro.
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