drbd: rcu_read_[un]lock() for all idr accesses that do not sleep

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

1 files changed, 29 insertions, 12 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index f08fb6f49cd8..60c171b17156 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -372,12 +372,14 @@ static enum drbd_fencing_p highest_fencing_policy(struct drbd_tconn *tconn)
         struct drbd_conf *mdev;
         int vnr;
 
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, vnr) {
                 if (get_ldev_if_state(mdev, D_CONSISTENT)) {
                         fp = max_t(enum drbd_fencing_p, fp, mdev->ldev->dc.fencing);
                         put_ldev(mdev);
                 }
         }
+        rcu_read_unlock();
 
         return fp;
 }
@@ -1624,29 +1626,41 @@ out:
 static bool conn_resync_running(struct drbd_tconn *tconn)
 {
         struct drbd_conf *mdev;
+        bool rv = false;
         int vnr;
 
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, vnr) {
                 if (mdev->state.conn == C_SYNC_SOURCE ||
                     mdev->state.conn == C_SYNC_TARGET ||
                     mdev->state.conn == C_PAUSED_SYNC_S ||
-                    mdev->state.conn == C_PAUSED_SYNC_T)
-                        return true;
+                    mdev->state.conn == C_PAUSED_SYNC_T) {
+                        rv = true;
+                        break;
+                }
         }
-        return false;
+        rcu_read_unlock();
+
+        return rv;
 }
 
 static bool conn_ov_running(struct drbd_tconn *tconn)
 {
         struct drbd_conf *mdev;
+        bool rv = false;
         int vnr;
 
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, vnr) {
                 if (mdev->state.conn == C_VERIFY_S ||
-                    mdev->state.conn == C_VERIFY_T)
-                        return true;
+                    mdev->state.conn == C_VERIFY_T) {
+                        rv = true;
+                        break;
+                }
         }
-        return false;
+        rcu_read_unlock();
+
+        return rv;
 }
 
 int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
@@ -1858,26 +1872,28 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
                 goto fail;
         }
 
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, i) {
                 if (get_ldev(mdev)) {
                         enum drbd_fencing_p fp = mdev->ldev->dc.fencing;
                         put_ldev(mdev);
                         if (new_conf->wire_protocol == DRBD_PROT_A && fp == FP_STONITH) {
                                 retcode = ERR_STONITH_AND_PROT_A;
-                                goto fail;
+                                goto fail_rcu_unlock;
                         }
                 }
                 if (mdev->state.role == R_PRIMARY && new_conf->want_lose) {
                         retcode = ERR_DISCARD;
-                        goto fail;
+                        goto fail_rcu_unlock;
                 }
                 if (!mdev->bitmap) {
                         if(drbd_bm_init(mdev)) {
                                 retcode = ERR_NOMEM;
-                                goto fail;
+                                goto fail_rcu_unlock;
                         }
                 }
         }
+        rcu_read_unlock();
 
         if (new_conf->on_congestion != OC_BLOCK && new_conf->wire_protocol != DRBD_PROT_A) {
                 retcode = ERR_CONG_NOT_PROTO_A;
@@ -1991,15 +2007,19 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
         retcode = _conn_request_state(tconn, NS(conn, C_UNCONNECTED), CS_VERBOSE);
         spin_unlock_irq(&tconn->req_lock);
 
+        rcu_read_lock();
         idr_for_each_entry(&tconn->volumes, mdev, i) {
                 mdev->send_cnt = 0;
                 mdev->recv_cnt = 0;
                 kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
         }
+        rcu_read_unlock();
         conn_reconfig_done(tconn);
         drbd_adm_finish(info, retcode);
         return 0;
 
+fail_rcu_unlock:
+        rcu_read_unlock();
 fail:
         kfree(int_dig_in);
         kfree(int_dig_vv);
@@ -2562,8 +2582,6 @@ int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
 
         /* synchronize with drbd_new_tconn/drbd_free_tconn */
         mutex_lock(&drbd_cfg_mutex);
-        /* synchronize with drbd_delete_device */
-        rcu_read_lock();
 next_tconn:
         /* revalidate iterator position */
         list_for_each_entry(tmp, &drbd_tconns, all_tconn) {
@@ -2624,7 +2642,6 @@ next_tconn:
         }
 
 out:
-        rcu_read_unlock();
         mutex_unlock(&drbd_cfg_mutex);
         /* where to start the next iteration */
         cb->args[0] = (long)pos;