* [patch 2/3] Introduce new "online" node for backend drivers.
@ 2006-08-31 7:41 Gerd Hoffmann
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From: Gerd Hoffmann @ 2006-08-31 7:41 UTC (permalink / raw)
To: xen-devel >> Xen devel list
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Hi,
This patch introduces a new "online" node for backend drivers.
Driver changes: Make backend drivers check it when entering Closed
state, only unregister devices when the "online" node is either "0" or
not present. The later maintains backward compatibility.
Tools changes: Update "online" node when creating and hot-unplugging
devices.
Background: When kexec'ing a new kernel, the old kernel's frontend
driver will shutdown, but the backend device should *NOT* disappear
due to that, so the new kernel instance can reconnect.
please apply,
Gerd
--
Gerd Hoffmann <kraxel@suse.de>
http://www.suse.de/~kraxel/julika-dora.jpeg
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Introduce new "online" node for backend drivers.
Driver changes: Make backend drivers check it when entering Closed
state, only unregister devices when the "online" node is either "0" or
not present. The later maintains backward compatibility.
Tools changes: Update "online" node when creating and hot-unplugging
devices.
Background: When kexec'ing a new kernel, the old kernel's frontend
driver will shutdown, but the backend device should *NOT* disappear
due to that, so the new kernel instance can reconnect.
Signed-off-by: Gerd Hoffmann <kraxel@suse.de>
---
linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c | 10 +++--
linux-2.6-xen-sparse/drivers/xen/blktap/common.h | 1
linux-2.6-xen-sparse/drivers/xen/blktap/interface.c | 19 ++++++----
linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c | 16 +++++++-
linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c | 10 +++--
linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c | 11 +++++
linux-2.6-xen-sparse/include/xen/xenbus.h | 1
tools/python/xen/xend/server/DevController.py | 6 ++-
8 files changed, 58 insertions(+), 16 deletions(-)
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
@@ -301,11 +301,11 @@ static void frontend_changed(struct xenb
struct backend_info *be = dev->dev.driver_data;
int err;
- DPRINTK("");
+ DPRINTK("%s", xenbus_strstate(frontend_state));
switch (frontend_state) {
case XenbusStateInitialising:
- if (dev->state == XenbusStateClosing) {
+ if (dev->state == XenbusStateClosed) {
printk("%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
xenbus_switch_state(dev, XenbusStateInitWait);
@@ -331,8 +331,12 @@ static void frontend_changed(struct xenb
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/netback/xenbus.c
@@ -228,13 +228,13 @@ static void frontend_changed(struct xenb
{
struct backend_info *be = dev->dev.driver_data;
- DPRINTK("");
+ DPRINTK("%s", xenbus_strstate(frontend_state));
be->frontend_state = frontend_state;
switch (frontend_state) {
case XenbusStateInitialising:
- if (dev->state == XenbusStateClosing) {
+ if (dev->state == XenbusStateClosed) {
printk("%s: %s: prepare for reconnect\n",
__FUNCTION__, dev->nodename);
if (be->netif) {
@@ -260,8 +260,12 @@ static void frontend_changed(struct xenb
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
if (be->netif != NULL)
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
device_unregister(&dev->dev);
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_backend_client.c
@@ -132,4 +132,15 @@ int xenbus_unmap_ring(struct xenbus_devi
}
EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
+int xenbus_dev_is_online(struct xenbus_device *dev)
+{
+ int rc, val;
+
+ rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
+ if (1 != rc)
+ val = 0; /* no online node present */
+ return val;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
+
MODULE_LICENSE("Dual BSD/GPL");
Index: build-32-unstable-11288/linux-2.6-xen-sparse/include/xen/xenbus.h
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/include/xen/xenbus.h
+++ build-32-unstable-11288/linux-2.6-xen-sparse/include/xen/xenbus.h
@@ -298,5 +298,6 @@ void xenbus_dev_fatal(struct xenbus_devi
int __init xenbus_dev_init(void);
char *xenbus_strstate(enum xenbus_state state);
+int xenbus_dev_is_online(struct xenbus_device *dev);
#endif /* _XEN_XENBUS_H */
Index: build-32-unstable-11288/tools/python/xen/xend/server/DevController.py
===================================================================
--- build-32-unstable-11288.orig/tools/python/xen/xend/server/DevController.py
+++ build-32-unstable-11288/tools/python/xen/xend/server/DevController.py
@@ -207,7 +207,8 @@ class DevController:
devid = int(devid)
- self.writeBackend(devid, 'state', str(xenbusState['Closing']))
+ self.writeBackend(devid, 'state', str(xenbusState['Closing']))
+ self.writeBackend(devid, 'online', "0")
def configurations(self):
@@ -406,7 +407,8 @@ class DevController:
'domain' : self.vm.getName(),
'frontend' : frontpath,
'frontend-id' : "%i" % self.vm.getDomid(),
- 'state' : str(xenbusState['Initialising'])
+ 'state' : str(xenbusState['Initialising']),
+ 'online' : "1"
})
return (backpath, frontpath)
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
@@ -247,6 +247,11 @@ static void tap_frontend_changed(struct
switch (frontend_state) {
case XenbusStateInitialising:
+ if (dev->state == XenbusStateClosed) {
+ printk("%s: %s: prepare for reconnect\n",
+ __FUNCTION__, dev->nodename);
+ xenbus_switch_state(dev, XenbusStateInitWait);
+ }
break;
case XenbusStateInitialised:
@@ -264,11 +269,20 @@ static void tap_frontend_changed(struct
break;
case XenbusStateClosing:
+ if (be->blkif->xenblkd) {
+ kthread_stop(be->blkif->xenblkd);
+ be->blkif->xenblkd = NULL;
+ }
+ tap_blkif_unmap(be->blkif);
xenbus_switch_state(dev, XenbusStateClosing);
break;
- case XenbusStateUnknown:
case XenbusStateClosed:
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through if not online */
+ case XenbusStateUnknown:
device_unregister(&dev->dev);
break;
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
@@ -91,6 +91,7 @@ blkif_t *tap_alloc_blkif(domid_t domid);
void tap_blkif_free(blkif_t *blkif);
int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn);
+void tap_blkif_unmap(blkif_t *blkif);
#define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
#define blkif_put(_b) \
Index: build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
===================================================================
--- build-32-unstable-11288.orig/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
+++ build-32-unstable-11288/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
@@ -135,20 +135,25 @@ int tap_blkif_map(blkif_t *blkif, unsign
return 0;
}
-void tap_blkif_free(blkif_t *blkif)
+void tap_blkif_unmap(blkif_t *blkif)
{
- atomic_dec(&blkif->refcnt);
- wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
-
- /* Already disconnected? */
- if (blkif->irq)
+ if (blkif->irq) {
unbind_from_irqhandler(blkif->irq, blkif);
-
+ blkif->irq = 0;
+ }
if (blkif->blk_ring.sring) {
unmap_frontend_page(blkif);
free_vm_area(blkif->blk_ring_area);
+ blkif->blk_ring.sring = NULL;
}
+}
+void tap_blkif_free(blkif_t *blkif)
+{
+ atomic_dec(&blkif->refcnt);
+ wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
+
+ tap_blkif_unmap(blkif);
kmem_cache_free(blkif_cachep, blkif);
}
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2006-08-31 7:41 [patch 2/3] Introduce new "online" node for backend drivers Gerd Hoffmann
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