lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 23 Dec 2008 10:08:50 -0800 (PST)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Krzysztof Halasa <khc@...waw.pl>
cc:	Harvey Harrison <harvey.harrison@...il.com>,
	Håkon Løvdal <hlovdal@...il.com>,
	Hannes Eder <hannes@...neseder.net>, netdev@...r.kernel.org,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 02/27] drivers/net: fix sparse warnings: make do-while
 a compound statement


On Tue, 23 Dec 2008, Krzysztof Halasa wrote:

> Harvey Harrison <harvey.harrison@...il.com> writes:
> 
> >> There are many ways to make the code more merge friendly at a cost of
> >> readability. Hope we don't go this way.
> >
> > Linus himself added that particular warning to sparse...may want to check
> > with him the reason for it.
> 
> Once again, this is a personal thing, and a harmless one.

It's more than that. I added the check after some person who had been 
programming the kernel (and thus was supposedly fluent in C) literally 
could not parse a macro that had "do x while (y)" in it.

Why? Because it's so uncommon, and because "while (y)" on its own means 
something totally different.

So the syntactic sugar to _always_ have do-while loops have that brace is 
a way to avoid one of the rather few places where the C language has 
syntax that is very context-dependent.

Another example of this is "sizeof". The kernel universally (I hope) has 
parenthesis around the sizeof argument, even though it's clearly not 
required by the C language. 

It's a coding standard. 

And quite frankly, anybody who works on gcc has no place complaining about 
sparse coding standard warnings. They are a _hell_ of a lot better than 
some of the really crazy warnings gcc spews out with "-W". At least the 
sparse warnings you can make go away while making the code more 
understandable. Some of the -W warnings are unfixable without breaking the 
source code.

		Linus
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists