Re: [RFC PATCH 1/6] kenrel.h: add ALIGN_OF_LAST_BIT()

[Michal Nazarewicz]

On Tue, 20 Mar 2012 11:21:19 +0100, Lai Jiangshan <laijs@xxxxxxxxxxxxxx> wrote:

> Get the biggest 2**y that x % (2**y) == 0 for the align value.
>
> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> ---
>  include/linux/kernel.h |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 5113462..2c439dc 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -44,6 +44,8 @@
>  #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
>  #define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)
> +#define ALIGN_OF_LAST_BIT(x)	((((x)^((x) - 1))>>1) + 1)

Wouldn't ALIGNMENT() be less confusing? After all, that's what this macro is
calculating, right? Alignment of given address.

> +
>  #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
> /*


--
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  MichaÅ âmina86â Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@xxxxxxxxxx>--------------ooO--(_)--Ooo--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/