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authorFilipe Manco <filipe.manco@neclab.eu>2016-09-15 17:10:46 +0200
committerDavid S. Miller <davem@davemloft.net>2016-09-17 09:56:02 -0400
commitcce94483e47e8e3d74cf4475dea33f9fd4b6ad9f (patch)
tree319883b04cf525b1ab41a6dd6d3f1f5df97443ec /drivers/net/xen-netback
parent4253ef8f6f81405e65304eef5a5b182c32dec915 (diff)
downloadlinux-cce94483e47e8e3d74cf4475dea33f9fd4b6ad9f.tar.bz2
xen-netback: fix error handling on netback_probe()
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 two new valid state transitions on set_backend_state(), from XenbusStateInitialising to XenbusStateClosed, and from XenbusStateInitialising to XenbusStateInitWait. Signed-off-by: Filipe Manco <filipe.manco@neclab.eu> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback')
-rw-r--r--drivers/net/xen-netback/xenbus.c46
1 files changed, 30 insertions, 16 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 6a31f2610c23..daf4c7867102 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -271,6 +271,11 @@ static int netback_probe(struct xenbus_device *dev,
be->dev = dev;
dev_set_drvdata(&dev->dev, be);
+ be->state = XenbusStateInitialising;
+ err = xenbus_switch_state(dev, XenbusStateInitialising);
+ if (err)
+ goto fail;
+
sg = 1;
do {
@@ -383,11 +388,6 @@ static int netback_probe(struct xenbus_device *dev,
be->hotplug_script = script;
- err = xenbus_switch_state(dev, XenbusStateInitWait);
- if (err)
- goto fail;
-
- be->state = XenbusStateInitWait;
/* This kicks hotplug scripts, so do it immediately. */
err = backend_create_xenvif(be);
@@ -492,20 +492,20 @@ static inline void backend_switch_state(struct backend_info *be,
/* Handle backend state transitions:
*
- * The backend state starts in InitWait and the following transitions are
+ * The backend state starts in Initialising and the following transitions are
* allowed.
*
- * InitWait -> Connected
- *
- * ^ \ |
- * | \ |
- * | \ |
- * | \ |
- * | \ |
- * | \ |
- * | V V
+ * Initialising -> InitWait -> Connected
+ * \
+ * \ ^ \ |
+ * \ | \ |
+ * \ | \ |
+ * \ | \ |
+ * \ | \ |
+ * \ | \ |
+ * V | V V
*
- * Closed <-> Closing
+ * Closed <-> Closing
*
* The state argument specifies the eventual state of the backend and the
* function transitions to that state via the shortest path.
@@ -515,6 +515,20 @@ static void set_backend_state(struct backend_info *be,
{
while (be->state != state) {
switch (be->state) {
+ case XenbusStateInitialising:
+ switch (state) {
+ case XenbusStateInitWait:
+ case XenbusStateConnected:
+ case XenbusStateClosing:
+ backend_switch_state(be, XenbusStateInitWait);
+ break;
+ case XenbusStateClosed:
+ backend_switch_state(be, XenbusStateClosed);
+ break;
+ default:
+ BUG();
+ }
+ break;
case XenbusStateClosed:
switch (state) {
case XenbusStateInitWait: