linux-kernel - RE: [PATCH] fs: fix local var type

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Message-ID: <b66e21d0f55b4f568c81bb9d5d22b7a7@AcuMS.aculab.com>
Date:   Thu, 23 Aug 2018 11:23:35 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Michal Hocko' <mhocko@...nel.org>, Weikang Shi <swkhack@...il.com>
CC:     "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "alexander.h.duyck@...el.com" <alexander.h.duyck@...el.com>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "mgorman@...e.de" <mgorman@...e.de>,
        "l.stach@...gutronix.de" <l.stach@...gutronix.de>,
        "vdavydov.dev@...il.com" <vdavydov.dev@...il.com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "my_email@...il.com" <my_email@...il.com>
Subject: RE: [PATCH] fs: fix local var type

From: Michal Hocko
> Sent: 23 August 2018 12:14
> 
> On Thu 23-08-18 01:59:14, Weikang Shi wrote:
> > In the seq_hex_dump function,the remaining variable is int, but it receive a type of size_t
> argument.
> > So I change the type of remaining
> 
> The changelog should explain _why_ we need this fix. Is any of the code
> path overflowing?
> 
> Besides that I do not think this fix is complete. What about linelen?
> 
> Why do we even need len to be size_t? Why it cannot be int as well. I
> strongly doubt we need more than 32b here.

Although you may well want 'unsigned int' to avoid the sign extension
instruction that gets added for x86_64 when a signed int is added
to a pointer.

	David

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