[PATCH] Talk_to_backend on xenbus_probe only if drv->probe was sucessful

[Murillo Bernardes <mfb@br.ibm.com>]

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Hi,

This patch makes xenbus_probe only call talk_to_backend if drv->probe() was 
sucessful.

There is no sense in add a watch before drv->probe, because if it fails the 
otherend_changed callback will be called and receive a struct with invalid 
pointers and we get a segfault (ooops).

-- 
Murillo Fernandes Bernardes
IBM Linux Technology Center

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# HG changeset patch
# User root@localhost.localdomain
# Node ID 9ecd0d7fc6693e2aaceeb5e8c28af84109e9d3d8
# Parent  bdcb115c667a12a5514517456639142c1273b0f1

Put watch on device node only if probe was sucessful.

This fix segfault on netfront when creating more than three network devices on domU.

Signed-off-by: Murillo F. Bernardes <mfb@br.ibm.com>

diff -r bdcb115c667a -r 9ecd0d7fc669 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c	Sat Dec 10 23:20:08 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c	Mon Dec 12 17:50:37 2005
@@ -338,6 +338,21 @@
 
 	DPRINTK("");
 
+	if (!drv->probe) {
+		err = -ENODEV;
+		goto fail;
+	}
+
+	id = match_device(drv->ids, dev);
+	if (!id) {
+		err = -ENODEV;
+		goto fail;
+	}
+
+	err = drv->probe(dev, id);
+	if (err)
+		goto fail;
+
 	err = talk_to_otherend(dev);
 	if (err) {
 		printk(KERN_WARNING
@@ -345,21 +360,6 @@
 		       dev->nodename);
 		return err;
 	}
-
-	if (!drv->probe) {
-		err = -ENODEV;
-		goto fail;
-	}
-
-	id = match_device(drv->ids, dev);
-	if (!id) {
-		err = -ENODEV;
-		goto fail;
-	}
-
-	err = drv->probe(dev, id);
-	if (err)
-		goto fail;
 
 	return 0;
 fail:

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