linux-kernel - Re: [PATCH 4/7] lib/random32.c: Use <asm/unaligned.h> instead of hand-rolling it

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Message-ID: <20140608124031.2571.qmail@ns.horizon.com>
Date:	8 Jun 2014 08:40:31 -0400
From:	"George Spelvin" <linux@...izon.com>
To:	dborkman@...hat.com, linux@...izon.com
Cc:	davem@...emloft.net, hannes@...essinduktion.org,
	linux-kernel@...r.kernel.org, shemminger@...l.org, tytso@....edu
Subject: Re: [PATCH 4/7] lib/random32.c: Use <asm/unaligned.h> instead of hand-rolling it

> Seems fine by me, since it's random anyway archs might not care
> about the *_le32, though this might yield additional work in some
> cases I presume.

If you think that's okay, sure.  I kept it consistent to get byte-for-byte
identical results.

If variations in that are allowed, that can also
simplify the trailing storage case:

+		if (bytes & 2)
+			put_unaligned_le16((u16)random, p+i);
+		if (bytes & 1)
+			p[i+bytes-1] = (u8)(random >> 16);

>> +	for (i = 0; i < round_down(bytes, sizeof(u32)); i += sizeof(u32))
>> +		put_unaligned_le32(prandom_u32_state(state), p+i);

> Nit: 'p + i'

I don't really care, but I'm happy without the spaces; I add them
to show what binds more weakly, and in this case that's the
argument-separating comma.

>> +		p[i] = (u8)random;

> Nit: '(u8) random'

Actually, my style and most of the kerel is to not put
a space in a cast, since it binds so tighty.

E.g. compare

git grep ')[a-z]' kernel/
git grep ') [a-z]' kernel/

Notice that the second is alsmost all comments.
(There are some spaces in kernel/ptrace.v.)

I'd rather leave it without the space unless you feel
very strongly about it.
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