This patch changes the probe notifier, per Rusty's suggestion. It
also converts the balloon driver to use the notifier structure, and
removes the root-watch workaround.
Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
diff -r a94ff69a51a3 linux-2.6-xen-sparse/arch/xen/kernel/reboot.c
--- a/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c Fri Aug 5 16:04:24 2005
+++ b/linux-2.6-xen-sparse/arch/xen/kernel/reboot.c Fri Aug 5 11:14:02 2005
@@ -314,6 +314,9 @@
static struct notifier_block xenstore_notifier;
+/* Setup our watcher
+ NB: Assumes xenbus_lock is held!
+*/
static int setup_shutdown_watcher(struct notifier_block *notifier,
unsigned long event,
void *data)
@@ -323,12 +326,12 @@
int err2 = 0;
#endif
- down(&xenbus_lock);
+ BUG_ON(down_trylock(&xenbus_lock) == 0);
+
err1 = register_xenbus_watch(&shutdown_watch);
#ifdef CONFIG_MAGIC_SYSRQ
err2 = register_xenbus_watch(&sysrq_watch);
#endif
- up(&xenbus_lock);
if (err1) {
printk(KERN_ERR "Failed to set shutdown watcher\n");
@@ -348,11 +351,7 @@
xenstore_notifier.notifier_call = setup_shutdown_watcher;
- if (xen_start_info.store_evtchn) {
- setup_shutdown_watcher(&xenstore_notifier, 0, NULL);
- } else {
- register_xenstore_notifier(&xenstore_notifier);
- }
+ register_xenstore_notifier(&xenstore_notifier);
return 0;
}
diff -r a94ff69a51a3 linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c
--- a/linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c Fri Aug 5
16:04:24 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c Fri Aug 5
11:14:02 2005
@@ -81,9 +81,6 @@
static DECLARE_WORK(balloon_worker, balloon_process, NULL);
static struct timer_list balloon_timer;
-/* Flag for dom0 xenstore workaround */
-static int balloon_xenbus_init=0;
-
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
/* Use the private and mapping fields of struct page as a list. */
#define PAGE_TO_LIST(p) ( (struct list_head *)&p->private )
@@ -304,15 +301,9 @@
schedule_work(&balloon_worker);
}
-static struct xenbus_watch xb_watch =
-{
- .node = "memory"
-};
-
-/* FIXME: This is part of a dom0 sequencing workaround */
-static struct xenbus_watch root_watch =
-{
- .node = "/"
+static struct xenbus_watch target_watch =
+{
+ .node = "memory/target"
};
/* React to a change in the target key */
@@ -320,30 +311,12 @@
{
unsigned long new_target;
int err;
-
- if(watch == &root_watch)
- {
- /* FIXME: This is part of a dom0 sequencing workaround */
- if(register_xenbus_watch(&xb_watch) == 0)
- {
- /*
- We successfully set a watch on memory/target:
- now we can stop watching root
- */
- unregister_xenbus_watch(&root_watch);
- balloon_xenbus_init=1;
- }
- else
- {
- return;
- }
- }
err = xenbus_scanf("memory", "target", "%lu", &new_target);
if(err != 1)
{
- IPRINTK("Unable to read memory/target\n");
+ printk(KERN_ERR "Unable to read memory/target\n");
return;
}
@@ -351,40 +324,26 @@
}
-/* Init Function - Try to set up our watcher, if not already set. */
-void balloon_init_watcher(void)
+/* Setup our watcher
+ NB: Assumes xenbus_lock is held!
+*/
+int balloon_init_watcher(struct notifier_block *notifier,
+ unsigned long event,
+ void *data)
{
int err;
- if (!xen_start_info.store_evtchn) {
- IPRINTK("Delaying watcher init until xenstore is available\n");
- return;
- }
-
- down(&xenbus_lock);
-
- if (!balloon_xenbus_init) {
- err = register_xenbus_watch(&xb_watch);
- if (err) {
- /* BIG FAT FIXME: dom0 sequencing workaround
- * dom0 can't set a watch on memory/target until
- * after the tools create it. So, we have to watch
- * the whole store until that happens.
- *
- * This will go away when we have the ability to watch
- * non-existant keys
- */
- register_xenbus_watch(&root_watch);
- } else {
- IPRINTK("Balloon xenbus watcher initialized\n");
- balloon_xenbus_init = 1;
- }
- }
-
- up(&xenbus_lock);
-}
-
-EXPORT_SYMBOL(balloon_init_watcher);
+ BUG_ON(down_trylock(&xenbus_lock) == 0);
+
+ err = register_xenbus_watch(&target_watch);
+
+ if (err) {
+ printk(KERN_ERR "Failed to set balloon watcher\n");
+ }
+
+ return NOTIFY_DONE;
+
+}
static int balloon_write(struct file *file, const char __user *buffer,
unsigned long count, void *data)
@@ -439,6 +398,8 @@
return len;
}
+static struct notifier_block xenstore_notifier;
+
static int __init balloon_init(void)
{
unsigned long pfn;
@@ -474,11 +435,11 @@
balloon_append(page);
}
- xb_watch.callback = watch_target;
- root_watch.callback = watch_target;
-
- balloon_init_watcher();
-
+ target_watch.callback = watch_target;
+ xenstore_notifier.notifier_call = balloon_init_watcher;
+
+ register_xenstore_notifier(&xenstore_notifier);
+
return 0;
}
diff -r a94ff69a51a3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Fri Aug 5
16:04:24 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c Fri Aug 5
11:14:02 2005
@@ -41,9 +41,6 @@
#define streq(a, b) (strcmp((a), (b)) == 0)
-/* Protects notifier chain */
-DECLARE_MUTEX(xenstore_control);
-
static struct notifier_block *xenstore_chain;
/* If something in array of ids matches this device, return it. */
@@ -317,21 +314,27 @@
int register_xenstore_notifier(struct notifier_block *nb)
{
- int ret;
-
- if ((ret = down_interruptible(&xenstore_control)) != 0)
- return ret;
- ret = notifier_chain_register(&xenstore_chain, nb);
- up(&xenstore_control);
+ int ret = 0;
+
+ down(&xenbus_lock);
+
+ if (xen_start_info.store_evtchn) {
+ ret = nb->notifier_call(nb, 0, NULL);
+ } else {
+ notifier_chain_register(&xenstore_chain, nb);
+ }
+
+ up(&xenbus_lock);
+
return ret;
}
EXPORT_SYMBOL(register_xenstore_notifier);
void unregister_xenstore_notifier(struct notifier_block *nb)
{
- down(&xenstore_control);
+ down(&xenbus_lock);
notifier_chain_unregister(&xenstore_chain, nb);
- up(&xenstore_control);
+ up(&xenbus_lock);
}
EXPORT_SYMBOL(unregister_xenstore_notifier);
@@ -349,7 +352,10 @@
return err;
}
+ down(&xenbus_lock);
err = notifier_call_chain(&xenstore_chain, 0, 0);
+ up(&xenbus_lock);
+
if (err == NOTIFY_BAD) {
printk("%s: calling xenstore notify chain failed\n",
__FUNCTION__);
@@ -358,9 +364,6 @@
err = 0;
- /* Initialize non-xenbus drivers */
- balloon_init_watcher();
-
down(&xenbus_lock);
/* Enumerate devices in xenstore. */
xenbus_probe_devices("device");
diff -r a94ff69a51a3 linux-2.6-xen-sparse/include/asm-xen/balloon.h
--- a/linux-2.6-xen-sparse/include/asm-xen/balloon.h Fri Aug 5 16:04:24 2005
+++ b/linux-2.6-xen-sparse/include/asm-xen/balloon.h Fri Aug 5 11:14:02 2005
@@ -48,7 +48,4 @@
#define balloon_lock(__flags) spin_lock_irqsave(&balloon_lock, __flags)
#define balloon_unlock(__flags) spin_unlock_irqrestore(&balloon_lock, __flags)
-/* Init Function - Try to set up our watcher, if not already set. */
-void balloon_init_watcher(void);
-
#endif /* __ASM_BALLOON_H__ */
--
Dan Smith
IBM Linux Technology Center
Open Hypervisor Team
email: danms@xxxxxxxxxx
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