linux-kernel - Re: [PATCH 0/5] sg

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: <20071221112834X.fujita.tomonori@lab.ntt.co.jp>
Date:	Fri, 21 Dec 2007 11:28:34 +0900
From:	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To:	rusty@...tcorp.com.au
Cc:	davem@...emloft.net, fujita.tomonori@....ntt.co.jp,
	linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
	jens.axboe@...cle.com, dougg@...que.net
Subject: Re: [PATCH 0/5] sg_ring for scsi

On Fri, 21 Dec 2007 10:13:38 +1100
Rusty Russell <rusty@...tcorp.com.au> wrote:

> On Thursday 20 December 2007 18:58:07 David Miller wrote:
> > From: Rusty Russell <rusty@...tcorp.com.au>
> > Date: Thu, 20 Dec 2007 18:53:48 +1100
> >
> > > Manipulating the magic chains is horrible; it looks simple to the
> > > places which simply want to iterate through it, but it's awful for
> > > code which wants to create them.
> >
> > I'm not saying complexity is inherent in this stuff, but
> > assuming that it is the complexity should live as far away
> > from the minions (the iterators in this case).  Therefore,
> > the creators is the right spot for the hard stuff.
> 
> In this case, the main benefit of the sg chaining was that the conversion of 
> most scsi drivers was easy (basically sg++ -> sg = sg_next(sg)).  The 
> conversion to sg_ring is more complex, but the end result is not 
> significantly more complex.
> 
> However, the cost to code which manipulates sg chains was significant: I tried 
> using them in virtio and it was too ugly to live (so that doesn't support sg 
> chaining).  If this was the best we could do, that'd be fine.
> 
> But, as demonstrated, there are real benefits of having an explicit header:

I'm not sure about chaining the headers (as your sg_ring and
scsi_sgtable do) would simplify LLDs. Have you looked at ips or
qla1280?
--
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/