On 14-09-2016 12:10, Wei Liu wrote:
CC xen-devel as well.
On Tue, Sep 13, 2016 at 02:11:27PM +0200, Filipe Manco wrote:
In case of error during netback_probe() (e.g. an entry missing on the
xenstore) netback_remove() is called on the new device, which will set
the device backend state to XenbusStateClosed by calling
set_backend_state(). However, the backend state wasn't initialized by
netback_probe() at this point, which will cause and invalid transaction
and set_backend_state() to BUG().
Initialize the backend state at the beginning of netback_probe() to
XenbusStateInitialising, and create a new valid state transaction on
set_backend_state(), from XenbusStateInitialising to XenbusStateClosed.
Signed-off-by: Filipe Manco <filipe.ma...@neclab.eu>
There is a state machine right before set_backend_state. You would also
need to update that.
Good point I'll update the diagram.
After looking at the diagram and for consistency, shouldn't the transition
Initialising -> InitWait be handled using set_backend_state()? Currently it
is done directly in netback_probe() code. If you agree I'll submit a v2 with
these two changes.
According to the definition of XenbusStateInitialising, this patch looks
plausible to me.
Wei.
Filipe
---
drivers/net/xen-netback/xenbus.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 6a31f2610c23..c0e5f6994d01 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -270,6 +270,7 @@ static int netback_probe(struct xenbus_device *dev,
be->dev = dev;
dev_set_drvdata(&dev->dev, be);
+ be->state = XenbusStateInitialising;
sg = 1;
@@ -515,6 +516,15 @@ static void set_backend_state(struct backend_info *be,
{
while (be->state != state) {
switch (be->state) {
+ case XenbusStateInitialising:
+ switch (state) {
+ case XenbusStateClosed:
+ backend_switch_state(be, XenbusStateClosed);
+ break;
+ default:
+ BUG();
+ }
+ break;
case XenbusStateClosed:
switch (state) {
case XenbusStateInitWait:
--
2.7.4
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