From: Changli Gao <xiaosuo@gmail.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
axboe@kernel.dk, viro@zeniv.linux.org.uk, mszeredi@suse.cz,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/4] splice: fix updating sd->pos wrongly
Date: Sat, 29 May 2010 22:22:54 +0800 [thread overview]
Message-ID: <AANLkTikycDykLRPnRZFAbdIszTOMDVFoX4DGiLcCvSqd@mail.gmail.com> (raw)
In-Reply-To: <20100529140901.GD3106@shareable.org>
On Sat, May 29, 2010 at 10:09 PM, Jamie Lokier <jamie@shareable.org> wrote:
>
> Not true if the "file" is /dev/mem or /dev/kmem. The starting offset
> can be negative, so can end at zero.
>
> It's an obscure case and I don't know if you can sendfile from
> /dev/{,k}mem anyway :-) but illustrates why sd->pos != 0 is dubious.
>
So the safe way is checking if splice_read() updates pos or not, isn't it?
if (sd->pos != prev_pos)
sd->pos = prev_pos + ret;
--
Regards，
Changli Gao(xiaosuo@gmail.com)
prev parent reply other threads:[~2010-05-29 14:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-26 14:44 [PATCH v2 4/4] splice: fix updating sd->pos wrongly Changli Gao
2010-05-28 9:42 ` Miklos Szeredi
2010-05-28 10:00 ` Changli Gao
2010-05-28 10:13 ` Miklos Szeredi
2010-05-28 10:55 ` Changli Gao
2010-05-28 11:11 ` Miklos Szeredi
2010-05-28 11:36 ` Changli Gao
2010-05-28 11:40 ` Miklos Szeredi
2010-05-29 14:09 ` Jamie Lokier
2010-05-29 14:22 ` Changli Gao [this message]
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