From: Andrew Morton <akpm@linux-foundation.org>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>,
"Jessica Yu" <jeyu@redhat.com>,
"Johannes Berg" <johannes.berg@intel.com>,
"Petr Mladek" <pmladek@suse.com>,
"Larry Finger" <Larry.Finger@lwfinger.net>,
linux-kernel@vger.kernel.org,
"Gustavo Padovan" <gustavo.padovan@collabora.co.uk>,
"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
"Peter Zijlstra" <peterz@infradead.org>,
"Luis de Bethencourt" <luisbg@osg.samsung.com>,
"Josh Triplett" <josh@joshtriplett.org>
Subject: Re: [PATCH] kernel.h: add IS_PTR_ALIGNED() macro
Date: Wed, 29 Mar 2017 14:36:56 -0700 [thread overview]
Message-ID: <20170329143656.d89a2f139316df3f39a91db9@linux-foundation.org> (raw)
In-Reply-To: <1490782930-30429-1-git-send-email-yamada.masahiro@socionext.com>
On Wed, 29 Mar 2017 19:22:10 +0900 Masahiro Yamada <yamada.masahiro@socionext.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.
prev parent reply other threads:[~2017-03-29 21:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 10:22 Masahiro Yamada
2017-03-29 21:24 ` H. Peter Anvin
2017-03-30 1:57 ` Masahiro Yamada
2017-03-30 3:29 ` H. Peter Anvin
2017-03-30 15:22 ` Masahiro Yamada
2017-03-29 21:36 ` Andrew Morton [this message]
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