ieee1394: run high-level updates before high-level probes

After a bus reset, let nodemgr call high-level update hooks first for nodes
which do not need to be probed.  The main benefit is for a bus with more
than one SBP-2 device:  SBP-2 reconnects will be performed before SBP-2
logins, thus have a much higher chance to succeed, and their SCSI devices
will not be blocked much longer than necessary.  This was demonstrated for
Linux 2.4 by Dave Cinege a while ago.

A better approach would be to perform time-consuming probes in parallel by a
subthread.  I actually plan to implement this for sbp2 but it may take a
while to get that done and tested.  Until then, this tweak is a huge
improvement for users with multiple SBP-2 devices.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jody McIntyre <scjody@modernduck.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index 01ab2bfa8d9d..0ec298768621 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -1407,14 +1407,28 @@ static void nodemgr_node_probe(struct host_info *hi, int generation)
         struct hpsb_host *host = hi->host;
         struct class *class = &nodemgr_ne_class;
         struct class_device *cdev;
+        struct node_entry *ne;
 
         /* Do some processing of the nodes we've probed. This pulls them
          * into the sysfs layer if needed, and can result in processing of
          * unit-directories, or just updating the node and it's
-         * unit-directories. */
+         * unit-directories.
+         *
+         * Run updates before probes. Usually, updates are time-critical
+         * while probes are time-consuming. (Well, those probes need some
+         * improvement...) */
+
         down_read(&class->subsys.rwsem);
-        list_for_each_entry(cdev, &class->children, node)
-                nodemgr_probe_ne(hi, container_of(cdev, struct node_entry, class_dev), generation);
+        list_for_each_entry(cdev, &class->children, node) {
+                ne = container_of(cdev, struct node_entry, class_dev);
+                if (!ne->needs_probe)
+                        nodemgr_probe_ne(hi, ne, generation);
+        }
+        list_for_each_entry(cdev, &class->children, node) {
+                ne = container_of(cdev, struct node_entry, class_dev);
+                if (ne->needs_probe)
+                        nodemgr_probe_ne(hi, ne, generation);
+        }
         up_read(&class->subsys.rwsem);