dm mpath: avoid attempting to activate null path

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>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 4840733cd903..58b1015260fa 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -441,13 +441,13 @@ static void process_queued_ios(struct work_struct *work)
                 __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;