From: "Dale Farnsworth" <dale@farnsworth.org>
To: "Steven J. Hill" <sjhill@realitydiluted.com>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] Merge GT/MV642xx Support into MV643xx Driver [7/8]
Date: Thu, 19 Jul 2007 20:40:43 -0700 [thread overview]
Message-ID: <20070720034043.GA28756@xyzzy.farnsworth.org> (raw)
In-Reply-To: <46A01992.1060907@realitydiluted.com>
On Thu, Jul 19, 2007 at 09:10:26PM -0500, Steven J. Hill wrote:
> Dale Farnsworth wrote:
> >
> > You have replaced the use of the global PHY spinlock with a per-port spinlock.
> > However, the SMI register is shared by all ports. The global lock is
> > needed to prevent simultaneous updates of the register by drivers for
> > multiple ports.
> >
> > NAK
> >
> Are you sure? Notice that a majority of the spinlocks were changed to disable
> IRQs. Secondly, the lowest level mv_read/mv_write functions have to acquire
> the big mv64x60_lock before they can read or write registers. I see the PHY
> spinlock as being an additional and unnecessary lock to contend with. Am I
> make an improper assumption?
I'm sure. (Of course, I could be wrong.) On an SMP (or fully
preemptive) system, disabling IRQs doesn't provide sufficient
protection. Nor does a per-port spinlock, since multiple ports
share the single register. It seems to me that a driver-scope
lock is required.
-Dale
prev parent reply other threads:[~2007-07-20 3:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-19 4:56 [PATCH] Merge GT/MV642xx Support into MV643xx Driver [7/8] Steven J. Hill
2007-07-19 14:21 ` Dale Farnsworth
2007-07-20 2:10 ` Steven J. Hill
2007-07-20 3:40 ` Dale Farnsworth [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070720034043.GA28756@xyzzy.farnsworth.org \
--to=dale@farnsworth.org \
--cc=netdev@vger.kernel.org \
--cc=sjhill@realitydiluted.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).