[Xen-changelog] [xen-unstable] [NET/BLK] back: Change the netback and blkback device drivers to allow

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxxx
# Node ID 3fc16c39f15e78d1ab1b1abf82a26cb631f7fca5
# Parent  cadf1df88d3e83b3c69100260880e0139b336b49
[NET/BLK] back: Change the netback and blkback device drivers to allow
and handle frontend state transition from "Closing" to "Initialising".
Instead of destroying the backend device then they wait for a
reconnect from the frontend.  Needed for domU kexec support, to hand over
devices from one kernel instance to the next.

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxx>
---
 linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c |    5 +++++
 linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c |   15 +++++++++++++++
 2 files changed, 20 insertions(+)

diff -r cadf1df88d3e -r 3fc16c39f15e 
linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Sat Aug 19 10:17:48 
2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Sat Aug 19 10:20:08 
2006 +0100
@@ -305,6 +305,11 @@ static void frontend_changed(struct xenb
 
        switch (frontend_state) {
        case XenbusStateInitialising:
+               if (dev->state == XenbusStateClosing) {
+                       printk("%s: %s: prepare for reconnect\n",
+                              __FUNCTION__, dev->nodename);
+                       xenbus_switch_state(dev, XenbusStateInitWait);
+               }
                break;
 
        case XenbusStateInitialised:
diff -r cadf1df88d3e -r 3fc16c39f15e 
linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
--- a/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c Sat Aug 19 10:17:48 
2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c Sat Aug 19 10:20:08 
2006 +0100
@@ -234,10 +234,25 @@ static void frontend_changed(struct xenb
 
        switch (frontend_state) {
        case XenbusStateInitialising:
+               if (dev->state == XenbusStateClosing) {
+                       printk("%s: %s: prepare for reconnect\n",
+                              __FUNCTION__, dev->nodename);
+                       if (be->netif) {
+                               netif_disconnect(be->netif);
+                               be->netif = NULL;
+                       }
+                       xenbus_switch_state(dev, XenbusStateInitWait);
+               }
+               break;
+
        case XenbusStateInitialised:
                break;
 
        case XenbusStateConnected:
+               if (!be->netif) {
+                       /* reconnect: setup be->netif */
+                       backend_changed(&be->backend_watch, NULL, 0);
+               }
                maybe_connect(be);
                break;
 

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