[dm-devel] [PATCH] Do not try to activate path if pgpath is NULL

[Chandra Seetharaman <sekharan us ibm com>]

Path activation code is called even when the pgpath is NULL. This could
lead to a panic in activate_path(). Such a panic is seen in -rt kernel.

This problem has been there before the pg_init() was moved to a
workqueue.

Signed-off-by: Chandra Seetharaman <sekharan us ibm com>
---

Index: linux-2.6.28-rc3/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6.28-rc3.orig/drivers/md/dm-mpath.c
+++ linux-2.6.28-rc3/drivers/md/dm-mpath.c
@@ -441,13 +441,13 @@ static void process_queued_ios(struct wo
 		__choose_pgpath(m);
 
 	pgpath = m->current_pgpath;
-	m->pgpath_to_activate = m->current_pgpath;
 
 	if ((pgpath && !m->queue_io) ||
 	    (!pgpath && !m->queue_if_no_path))
 		must_queue = 0;
 
-	if (m->pg_init_required && !m->pg_init_in_progress) {
+	if (m->pg_init_required && !m->pg_init_in_progress && pgpath) {
+		m->pgpath_to_activate = pgpath;
 		m->pg_init_count++;
 		m->pg_init_required = 0;
 		m->pg_init_in_progress = 1;