WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH] pciback: deferred handling of pci configuration spac

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH] pciback: deferred handling of pci configuration space accesses
From: Ryan <hap9@xxxxxxxxxxxxxx>
Date: Mon, 24 Apr 2006 09:52:45 -0400
Delivery-date: Mon, 24 Apr 2006 06:52:48 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Some of the Linux PCI functions called by the virtual configuration
space handlers were making calls into ACPI code which uses semaphores.
Since semaphores can not be locked while atomic (because they could
sleep), I changed the way the PCI backend responds to requests from the
frontend. Previously, the virtual configuration space handlers ran in
the same context as the event channel interrupt handler (which was often
atomic if not always atomic). Now the interrupt handler schedules a
callback function (a bottom half) in the system work queue (keventd)
that will get called in process context at a slightly later time. This
allows the handlers in the virtual configuration space to run in process
context and to call any core PCI function regardless of whether it will
sleep or not.

This patch was previously submitted as part of a larger patch. There
have been no significant changes, just renamed a variable and made this
code independent of the other patch.

Signed-off-by: Ryan Wilson <hap9@xxxxxxxxxxxxxx>

Attachment: pciback_op_workqueue.patch
Description: Text Data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel