This is a note to let you know that I've just added the patch titled
9p/xen: fix connection sequence
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
9p-xen-fix-connection-sequence.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ae4427cdbf31e1b54eb284fe90df0d9c1abca108
Author: Juergen Gross <jgross@xxxxxxxx>
Date: Mon Jan 30 12:30:36 2023 +0100
9p/xen: fix connection sequence
[ Upstream commit c15fe55d14b3b4ded5af2a3260877460a6ffb8ad ]
Today the connection sequence of the Xen 9pfs frontend doesn't match
the documented sequence. It can work reliably only for a PV 9pfs device
having been added at boot time already, as the frontend is not waiting
for the backend to have set its state to "XenbusStateInitWait" before
reading the backend properties from Xenstore.
Fix that by following the documented sequence [1] (the documentation
has a bug, so the reference is for the patch fixing that).
[1]: https://lore.kernel.org/xen-devel/20230130090937.31623-1-jgross@xxxxxxxx/T/#u
Link: https://lkml.kernel.org/r/20230130113036.7087-3-jgross@xxxxxxxx
Fixes: 868eb122739a ("xen/9pfs: introduce Xen 9pfs transport driver")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
Signed-off-by: Eric Van Hensbergen <ericvh@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index 131757aa0e6e2..67e9a7085e13b 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -389,12 +389,11 @@ static int xen_9pfs_front_alloc_dataring(struct xenbus_device *dev,
return ret;
}
-static int xen_9pfs_front_probe(struct xenbus_device *dev,
- const struct xenbus_device_id *id)
+static int xen_9pfs_front_init(struct xenbus_device *dev)
{
int ret, i;
struct xenbus_transaction xbt;
- struct xen_9pfs_front_priv *priv = NULL;
+ struct xen_9pfs_front_priv *priv = dev_get_drvdata(&dev->dev);
char *versions, *v;
unsigned int max_rings, max_ring_order, len = 0;
@@ -420,11 +419,6 @@ static int xen_9pfs_front_probe(struct xenbus_device *dev,
if (max_ring_order < XEN_9PFS_RING_ORDER)
return -EINVAL;
- priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
-
- priv->dev = dev;
priv->num_rings = XEN_9PFS_NUM_RINGS;
priv->rings = kcalloc(priv->num_rings, sizeof(*priv->rings),
GFP_KERNEL);
@@ -482,23 +476,35 @@ static int xen_9pfs_front_probe(struct xenbus_device *dev,
goto error;
}
- write_lock(&xen_9pfs_lock);
- list_add_tail(&priv->list, &xen_9pfs_devs);
- write_unlock(&xen_9pfs_lock);
- dev_set_drvdata(&dev->dev, priv);
- xenbus_switch_state(dev, XenbusStateInitialised);
-
return 0;
error_xenbus:
xenbus_transaction_end(xbt, 1);
xenbus_dev_fatal(dev, ret, "writing xenstore");
error:
- dev_set_drvdata(&dev->dev, NULL);
xen_9pfs_front_free(priv);
return ret;
}
+static int xen_9pfs_front_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ struct xen_9pfs_front_priv *priv = NULL;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+ dev_set_drvdata(&dev->dev, priv);
+
+ write_lock(&xen_9pfs_lock);
+ list_add_tail(&priv->list, &xen_9pfs_devs);
+ write_unlock(&xen_9pfs_lock);
+
+ return 0;
+}
+
static int xen_9pfs_front_resume(struct xenbus_device *dev)
{
dev_warn(&dev->dev, "suspend/resume unsupported\n");
@@ -517,6 +523,8 @@ static void xen_9pfs_front_changed(struct xenbus_device *dev,
break;
case XenbusStateInitWait:
+ if (!xen_9pfs_front_init(dev))
+ xenbus_switch_state(dev, XenbusStateInitialised);
break;
case XenbusStateConnected:
