On 25/12/17 11:20, Eytan Heidingsfeld wrote:
I retried with DEBUG=xenbus and saw that xenbus_probe_type failed for
the device: device/suspend/event-channel (I think because it doesn't
have a backend key - it is empty). As this device isn't critical for the
usage of netfront I just commented out the error in xenbus_probe_type
for one device and now it works fine.
Is there any reason failing to probe the type of one device should fail
the whole probe of the xenbus?
I can formalize a patch the prints a warning with DBG and allows it to
continue but I was wondering if there was any downside to that?
Does the attached (untested) patch fix the problem? This patch skips
probing any device type for which we don't have a driver anyway.
Thanks,
Michael
diff --git a/src/interface/xen/xenbus.c b/src/interface/xen/xenbus.c
index c328af4..5dd01df 100644
--- a/src/interface/xen/xenbus.c
+++ b/src/interface/xen/xenbus.c
@@ -206,13 +206,14 @@ static struct xen_driver * xenbus_find_driver ( const char *type ) {
*
* @v xen Xen hypervisor
* @v parent Parent device
- * @v type Device type
* @v instance Device instance
+ * @v driver Device driver
* @ret rc Return status code
*/
static int xenbus_probe_device ( struct xen_hypervisor *xen,
- struct device *parent, const char *type,
- const char *instance ) {
+ struct device *parent, const char *instance,
+ struct xen_driver *driver ) {
+ const char *type = driver->type;
struct xen_device *xendev;
size_t key_len;
int rc;
@@ -234,6 +235,10 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,
xendev->xen = xen;
xendev->key = ( ( void * ) ( xendev + 1 ) );
snprintf ( xendev->key, key_len, "device/%s/%s", type, instance );
+ xendev->driver = driver;
+ xendev->dev.driver_name = driver->name;
+ DBGC ( xendev, "XENBUS %s has driver \"%s\"\n", xendev->key,
+ xendev->driver->name );
/* Read backend key */
if ( ( rc = xenstore_read ( xen, &xendev->backend, xendev->key,
@@ -253,18 +258,6 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,
DBGC ( xendev, "XENBUS %s backend=\"%s\" in domain %ld\n",
xendev->key, xendev->backend, xendev->backend_id );
- /* Look for a driver */
- xendev->driver = xenbus_find_driver ( type );
- if ( ! xendev->driver ) {
- DBGC ( xendev, "XENBUS %s has no driver\n", xendev->key );
- /* Not a fatal error */
- rc = 0;
- goto err_no_driver;
- }
- xendev->dev.driver_name = xendev->driver->name;
- DBGC ( xendev, "XENBUS %s has driver \"%s\"\n", xendev->key,
- xendev->driver->name );
-
/* Probe driver */
if ( ( rc = xendev->driver->probe ( xendev ) ) != 0 ) {
DBGC ( xendev, "XENBUS could not probe %s: %s\n",
@@ -276,7 +269,6 @@ static int xenbus_probe_device ( struct xen_hypervisor *xen,
xendev->driver->remove ( xendev );
err_probe:
- err_no_driver:
err_read_backend_id:
free ( xendev->backend );
err_read_backend:
@@ -310,11 +302,21 @@ static void xenbus_remove_device ( struct xen_device *xendev ) {
*/
static int xenbus_probe_type ( struct xen_hypervisor *xen,
struct device *parent, const char *type ) {
+ struct xen_driver *driver;
char *children;
char *child;
size_t len;
int rc;
+ /* Look for a driver */
+ driver = xenbus_find_driver ( type );
+ if ( ! driver ) {
+ DBGC ( xen, "XENBUS has no driver for \"%s\" devices\n", type );
+ /* Not a fatal error */
+ rc = 0;
+ goto err_no_driver;
+ }
+
/* Get children of this key */
if ( ( rc = xenstore_directory ( xen, &children, &len, "device",
type, NULL ) ) != 0 ) {
@@ -326,8 +328,8 @@ static int xenbus_probe_type ( struct xen_hypervisor *xen,
/* Probe each child */
for ( child = children ; child < ( children + len ) ;
child += ( strlen ( child ) + 1 /* NUL */ ) ) {
- if ( ( rc = xenbus_probe_device ( xen, parent, type,
- child ) ) != 0 )
+ if ( ( rc = xenbus_probe_device ( xen, parent, child,
+ driver ) ) != 0 )
goto err_probe_device;
}
@@ -337,6 +339,7 @@ static int xenbus_probe_type ( struct xen_hypervisor *xen,
err_probe_device:
free ( children );
err_directory:
+ err_no_driver:
return rc;
}
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