drbd: rcu_read_lock() and rcu_dereference() for tconn->net_conf

Removing the get_net_conf()/put_net_conf() calls

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 4025d0883bad..792a71ec2e69 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -197,6 +197,8 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
         int i, prev_i = -1;
         const char *sn;
         struct drbd_conf *mdev;
+        struct net_conf *nc;
+        char wp;
 
         static char write_ordering_chars[] = {
                 [WO_none] = 'n',
@@ -240,6 +242,10 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
                     mdev->state.role == R_SECONDARY) {
                         seq_printf(seq, "%2d: cs:Unconfigured\n", i);
                 } else {
+                        rcu_read_lock();
+                        nc = rcu_dereference(mdev->tconn->net_conf);
+                        wp = nc ? nc->wire_protocol - DRBD_PROT_A + 'A' : ' ';
+                        rcu_read_unlock();
                         seq_printf(seq,
                            "%2d: cs:%s ro:%s/%s ds:%s/%s %c %c%c%c%c%c%c\n"
                            "    ns:%u nr:%u dw:%u dr:%u al:%u bm:%u "
@@ -249,8 +255,7 @@ static int drbd_seq_show(struct seq_file *seq, void *v)
                            drbd_role_str(mdev->state.peer),
                            drbd_disk_str(mdev->state.disk),
                            drbd_disk_str(mdev->state.pdsk),
-                           (mdev->tconn->net_conf == NULL ? ' ' :
-                            (mdev->tconn->net_conf->wire_protocol - DRBD_PROT_A+'A')),
+                           wp,
                            drbd_suspended(mdev) ? 's' : 'r',
                            mdev->state.aftr_isp ? 'a' : '-',
                            mdev->state.peer_isp ? 'p' : '-',