linux-kernel - Re: __user with scalar data types

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Message-ID: <20170619163438.GE10672@ZenIV.linux.org.uk>
Date:   Mon, 19 Jun 2017 17:34:38 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     linux-sparse@...r.kernel.org, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: __user with scalar data types

On Mon, Jun 19, 2017 at 10:15:09AM -0600, Jordan Crouse wrote:

> Which raised a bikeshed debate over whether it is appropriate to mark a scalar
> type as __user.  My opinion is that it is appropriate because __user should mark
> user memory regardless of the container.

What the hell?  __user is a qualifier like const, volatile, etc.  It's a property
of *pointer* *type*.  Not some nebulous "marks userland memory" thing.

> I'm looking for opinions or semi-authoritative edicts to determine if we should
> either start changing our uapi headers or go off and try to figure out how to
> make sparse understand this particular usage.

Stop cargo-culting, please.