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Date:   Sun, 6 Oct 2019 21:47:03 +1100
From:   Aleksa Sarai <cyphar@cyphar.com>
To:     Christian Brauner <christian.brauner@ubuntu.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lib: test_user_copy: style cleanup
Message-ID: <20191006104703.jqn7qfcjlflgx5sp@yavin.dot.cyphar.com>
References: <20191005233028.18566-1-cyphar@cyphar.com>
 <20191006084102.mhqrsyg5slbfwejd@wittgenstein>
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On 2019-10-06, Christian Brauner <christian.brauner@ubuntu.com> wrote:
> On Sun, Oct 06, 2019 at 10:30:28AM +1100, Aleksa Sarai wrote:
> > While writing the tests for copy_struct_from_user(), I used a construct
> > that Linus doesn't appear to be too fond of:
> >=20
> > On 2019-10-04, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > > Hmm. That code is ugly, both before and after the fix.
> > >
> > > This just doesn't make sense for so many reasons:
> > >
> > >         if ((ret |=3D test(umem_src =3D=3D NULL, "kmalloc failed")))
> > >
> > > where the insanity comes from
> > >
> > >  - why "|=3D" when you know that "ret" was zero before (and it had to
> > >    be, for the test to make sense)
> > >
> > >  - why do this as a single line anyway?
> > >
> > >  - don't do the stupid "double parenthesis" to hide a warning. Make it
> > >    use an actual comparison if you add a layer of parentheses.
> >=20
> > So instead, use a bog-standard check that isn't nearly as ugly.
> >=20
> > Fixes: 341115822f88 ("usercopy: Add parentheses around assignment in te=
st_copy_struct_from_user")
> > Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
> > Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
>=20
> Fwiw, I think the commit message doesn't necessarily need to mention
> stylistic preferences nor a specific mail. It's sufficient enough to say
> that the new way makes things way more obvious. But ok. :)
>=20
> I'll pick this up now.

Thanks, and feel free to rewrite the commit message to whatever you'd
prefer.

--=20
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

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