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From: Minchan Kim <minchan@kernel.org>
Date: Mon, 8 Jan 2018 00:04:38 +0900
Message-ID: <CAEwNFnC9FA44y1vCWmm=LEyQHjJC=Sd8GzbYgY6rS9h9i2HOiw@mail.gmail.com>
Subject: Re: [PATCH] zsmalloc: use U suffix for negative literals being shifted
To: Nick Desaulniers <nick.desaulniers@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        linux-mm <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org

Hello,

Sorry for the delay. I have missed this until now. ;-(

On Sun, Dec 24, 2017 at 11:33 AM, Nick Desaulniers
<nick.desaulniers@gmail.com> wrote:
> Fixes warnings about shifting unsigned literals being undefined
> behavior.
>
> Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
> ---
>  mm/zsmalloc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 685049a..5d31458 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1056,7 +1056,7 @@ static void init_zspage(struct size_class *class, struct zspage *zspage)
>                          * Reset OBJ_TAG_BITS bit to last link to tell
>                          * whether it's allocated object or not.
>                          */
> -                       link->next = -1 << OBJ_TAG_BITS;
> +                       link->next = -1U << OBJ_TAG_BITS;

-1UL?

Please, resend it with including Andrew Morton
<akpm@linux-foundation.org> who merges zsmalloc patch into his tree.

Thanks.