lguest: update commentry
Every so often, after code shuffles, I need to go through and unbitrot
the Lguest Journey (see drivers/lguest/README). Since we now use RCU in
a simple form in one place I took the opportunity to expand that explanation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index cd058bc..1e2cb84 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -217,10 +217,15 @@
/*
* It's possible the Guest did a NOTIFY hypercall to the
- * Launcher, in which case we return from the read() now.
+ * Launcher.
*/
if (cpu->pending_notify) {
+ /*
+ * Does it just needs to write to a registered
+ * eventfd (ie. the appropriate virtqueue thread)?
+ */
if (!send_notify_to_eventfd(cpu)) {
+ /* OK, we tell the main Laucher. */
if (put_user(cpu->pending_notify, user))
return -EFAULT;
return sizeof(cpu->pending_notify);