Date: Wed, 18 Nov 2009 18:16:06 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jamie Lokier <jamie@shareable.org>
Cc: Oliver Neukum <oliver@neukum.org>, Jan Blunck <jblunck@suse.de>,
       linux-fsdevel@vger.kernel.org,
       Linux-Kernel Mailinglist <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>, jkacur@redhat.com,
       Thomas Gleixner <tglx@linutronix.de>, Arnd Bergmann <arnd@arndb.de>,
       Christoph Hellwig <hch@infradead.org>,
       =?ISO-8859-14?B?RnLpZOlyaWM=?= Weisbecker <fweisbec@gmail.com>,
       Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 1/2] BKL: Remove BKL from default_llseek()
Message-ID: <20091118181606.1c8caab1@lxorguk.ukuu.org.uk>
In-Reply-To: <20091118175003.GF28723@shareable.org>
References: <1258560457-15129-1-git-send-email-jblunck@suse.de>
	<20091118171524.4d2f8cec@lxorguk.ukuu.org.uk>
	<20091118172730.GD28723@shareable.org>
	<200911181835.55007.oliver@neukum.org>
	<20091118175003.GF28723@shareable.org>
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O> But nowadays, even that doesn't happen.  sys_read() and sys_write()
> make a copy of f_pos using file_pos_read(), so drivers cannot see the
> value change during the call - except for their own change.
> 
> I find myself wondering why the VFS isn't responsible for the position
> update instead of the driver...  Would it be a valid cleanup to move
> it from the driver to VFS?

And how would you adjust it. Not all devices have a bytes read == offset
relationship. The VFS doesn't know enough.
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