From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Khalid Aziz <khalid.aziz@hp.com>
Cc: linux-kernel@vger.kernel.org, bhelgaas@google.com,
linux-pci@vger.kernel.org
Subject: Re: [PATCH] Disable Bus Master on PCI device shutdown
Date: Wed, 6 Jun 2012 17:27:04 +0100 [thread overview]
Message-ID: <20120606162703.GA6779@srcf.ucam.org> (raw)
In-Reply-To: <1338999463.25761.630.camel@lyra>
On Wed, Jun 06, 2012 at 10:17:43AM -0600, Khalid Aziz wrote:
> That is a good piece of information. I see your concern and agree with
> it. My take is shutdown method for the drivers will end all active I/O
> and clear the I/O queue. This should take care of any DMA caused by an
> I/O request originating in the kernel. For devices like NIC, a DMA can
> be triggered by an incoming packet and I am trying to stop that by
> disabling Bus Master bit. This is the issue that was reported on kexec
> mailing list in July of last year and it involved qla driver. I observed
> similar problem with kexec on ia64 many years ago and had written a
> patch to disable Bus Master bit on kexec. This patch was in ia64 tree
> for some time before it was removed. HP shipped kernels with this patch
> for many years and those kernels have been in deployment in field for
> some 7+ years with no problems.
If the qla driver knows that this is safe, then can't this just be done
in the qla driver?
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-06-06 16:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 19:00 [PATCH] Disable Bus Master on PCI device shutdown Khalid Aziz
2012-05-03 23:52 ` Bjorn Helgaas
2012-05-04 17:15 ` Bjorn Helgaas
2012-06-06 13:50 ` Matthew Garrett
2012-06-06 16:17 ` Khalid Aziz
2012-06-06 16:27 ` Matthew Garrett [this message]
2012-06-06 17:32 ` Khalid Aziz
2012-06-06 17:42 ` Matthew Garrett
2012-06-06 18:07 ` Khalid Aziz
2012-06-06 19:42 ` Eric W. Biederman
2012-06-06 20:09 ` Matthew Garrett
2012-06-07 17:43 ` Khalid Aziz
2012-06-07 14:21 ` Khalid Aziz
2012-06-06 20:16 ` Myron Stowe
2012-06-06 23:03 ` Khalid Aziz
2012-06-06 23:18 ` Myron Stowe
2012-06-06 20:50 ` Alan Cox
2012-06-07 17:07 ` Andi Kleen
2012-06-07 17:13 ` Alan Cox
2012-06-07 17:36 ` Khalid Aziz
2012-06-07 17:08 ` Andi Kleen
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=20120606162703.GA6779@srcf.ucam.org \
--to=mjg59@srcf.ucam.org \
--cc=bhelgaas@google.com \
--cc=khalid.aziz@hp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
/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).