The following commit has been merged in the master branch:
commit 3b2582c7affde5f30bcc8321385507e66f4299e1
Author: Sven Eckelmann <sven(a)narfation.org>
Date: Sun Feb 16 18:30:12 2020 +0100
batman-adv: Avoid RCU list-traversal in spinlock
The new CONFIG_PROVE_RCU_LIST requires a condition statement in
(h)list_for_each_entry_rcu when the code might be executed in a non RCU
non-reader section with the writer lock. Otherwise lockdep might cause a
false positive warning like
=============================
WARNING: suspicious RCU usage
-----------------------------
translation-table.c:940 RCU-list traversed in non-reader section!!
batman-adv is (mostly) following the examples from the RCU documentation
and is using the normal list-traversal primitives instead of the RCU
list-traversal primitives when the writer (spin)lock is held.
The remaining users of RCU list-traversal primitives with writer spinlock
have to be converted to the same style as the rest of the code.
Reported-by: Madhuparna Bhowmik <madhuparnabhowmik10(a)gmail.com>
Signed-off-by: Sven Eckelmann <sven(a)narfation.org>
Signed-off-by: Simon Wunderlich <sw(a)simonwunderlich.de>
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 852932838ddc..a9635c882fe0 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -862,7 +862,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node *orig_node,
u8 *tt_change_ptr;
spin_lock_bh(&orig_node->vlan_list_lock);
- hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
+ hlist_for_each_entry(vlan, &orig_node->vlan_list, list) {
num_vlan++;
num_entries += atomic_read(&vlan->tt.num_entries);
}
@@ -888,7 +888,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node *orig_node,
(*tt_data)->num_vlan = htons(num_vlan);
tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
- hlist_for_each_entry_rcu(vlan, &orig_node->vlan_list, list) {
+ hlist_for_each_entry(vlan, &orig_node->vlan_list, list) {
tt_vlan->vid = htons(vlan->vid);
tt_vlan->crc = htonl(vlan->tt.crc);
@@ -937,7 +937,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv,
int change_offset;
spin_lock_bh(&bat_priv->softif_vlan_list_lock);
- hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
+ hlist_for_each_entry(vlan, &bat_priv->softif_vlan_list, list) {
vlan_entries = atomic_read(&vlan->tt.num_entries);
if (vlan_entries < 1)
continue;
@@ -967,7 +967,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv,
(*tt_data)->num_vlan = htons(num_vlan);
tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
- hlist_for_each_entry_rcu(vlan, &bat_priv->softif_vlan_list, list) {
+ hlist_for_each_entry(vlan, &bat_priv->softif_vlan_list, list) {
vlan_entries = atomic_read(&vlan->tt.num_entries);
if (vlan_entries < 1)
continue;
--
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