linux-kernel - Re: [PATCH] arch/tile: Add driver to enable access to the user dynamic network.

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 linux-hardening linux-cve-announce 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]

Message-ID: <4C28BE64.4050505@tilera.com>
Date:	Mon, 28 Jun 2010 11:23:16 -0400
From:	Chris Metcalf <cmetcalf@...era.com>
To:	Arnd Bergmann <arnd@...db.de>
CC:	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arch/tile: Add driver to enable access to the user dynamic
 network.

On 6/28/2010 7:12 AM, Arnd Bergmann wrote:
> On Sunday 27 June 2010, Chris Metcalf wrote:
>   
>> On 6/26/2010 7:16 AM, Arnd Bergmann wrote:
>>     
>>> It seems strange that you need this. Why does linux/list.h
>>> depend on asm/processor.h?
>>>       
>> <linux/list.h> -> <linux/poison.h> -> <linux/prefetch.h> ->
>> <asm/processor.h>.  There doesn't seem to be any good way around this. 
>> I could, I suppose, use an opaque "struct list_head;" declaration in
>> <asm/processor.h>, then create one with kmalloc on demand, but that
>> seemed like overkill, so I embed the made-up version here, then validate
>> it as a BUILD_BUG_ON() to be the same size as a real list_head.  I never
>> actually use the "hardwall_list" structure directly.
>>     
> We could break the dependency by turning prefetch_range into a macro
> or an extern function. There is only one user, and it's in a staging
> driver, so the impact would be minimal.
>   

I don't think so.  The problem is that users of <linux/list.h> expect to
be able to #include that one header, then use things like
list_for_each() (which uses prefetch, as defined in <asm/processor.h>),
but without also being required to #include <asm/processor.h> themselves
explicitly.

I think the only "true" fix would be to have a new <linux/list_types.h>
header that provides list_head (and presumably hlist_head and
hlist_node), which <linux/list.h> would include, as would our
<asm/processor.h>.  This is certainly in line with recent
header-separation changes (e.g. mm_types.h).  Would there be interest in
a change like this?  I implemented it in my tree, and if it sounds
plausible to you, I'll send out a git diff, but it looks pretty much
exactly like this description :-)

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/