[PATCH net-next 5/9] vxlan: move VXLAN_F_MDB to struct vxlan_dev flags
From: Eric Dumazet <edumazet@google.com>
Date: 2026-09-03 12:08:50
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
VXLAN_F_MDB is an internal runtime state flag indicating whether any MDB entries are configured on the device, rather than a netlink configuration attribute. In preparation for converting vxlan->cfg to an RCU-protected pointer, move VXLAN_F_MDB from struct vxlan_config to a dedicated 'flags' field in struct vxlan_dev as VXLAN_DEV_F_MDB, using atomic bitops (set_bit(), clear_bit(), test_bit()) to avoid KCSAN data races between the TX path and RTNL operations. This avoids having to dynamically reallocate and publish a new vxlan_config structure via RCU whenever the first MDB entry is added or the last one is removed, and prevents potential memory allocation failures during MDB teardown under memory pressure. Signed-off-by: Eric Dumazet <edumazet@google.com> --- drivers/net/vxlan/vxlan_core.c | 2 +- drivers/net/vxlan/vxlan_mdb.c | 6 +++--- include/net/vxlan.h | 6 +++++- 3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 2627e26f3699ff39e7e907b6f5f8f684d2d1235a..0fcc7282e69d08c4b94ce89ce99feeee576fabff 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c@@ -2809,7 +2809,7 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev) if (nhid) return vxlan_xmit_nhid(skb, dev, nhid, vni, saddr_family, cfg); - if (flags & VXLAN_F_MDB) { + if (test_bit(VXLAN_DEV_F_MDB, &vxlan->flags)) { struct vxlan_mdb_entry *mdb_entry; rcu_read_lock();
diff --git a/drivers/net/vxlan/vxlan_mdb.c b/drivers/net/vxlan/vxlan_mdb.c
index 6e38acbc8fea9e076aa6c50db1d273aeb65788e4..fe079d6abc5fcfb8bdac4d27b95dabd30aa10526 100644
--- a/drivers/net/vxlan/vxlan_mdb.c
+++ b/drivers/net/vxlan/vxlan_mdb.c@@ -1211,7 +1211,7 @@ vxlan_mdb_entry_get(struct vxlan_dev *vxlan, goto err_free_entry; if (hlist_is_singular_node(&mdb_entry->mdb_node, &vxlan->mdb_list)) - vxlan->cfg.flags |= VXLAN_F_MDB; + set_bit(VXLAN_DEV_F_MDB, &vxlan->flags); return mdb_entry;
@@ -1228,7 +1228,7 @@ static void vxlan_mdb_entry_put(struct vxlan_dev *vxlan, return; if (hlist_is_singular_node(&mdb_entry->mdb_node, &vxlan->mdb_list)) - vxlan->cfg.flags &= ~VXLAN_F_MDB; + clear_bit(VXLAN_DEV_F_MDB, &vxlan->flags); rhashtable_remove_fast(&vxlan->mdb_tbl, &mdb_entry->rhnode, vxlan_mdb_rht_params);
@@ -1754,7 +1754,7 @@ void vxlan_mdb_fini(struct vxlan_dev *vxlan) struct vxlan_mdb_flush_desc desc = {}; vxlan_mdb_flush(vxlan, &desc); - WARN_ON_ONCE(vxlan->cfg.flags & VXLAN_F_MDB); + WARN_ON_ONCE(test_bit(VXLAN_DEV_F_MDB, &vxlan->flags)); rhashtable_free_and_destroy(&vxlan->mdb_tbl, vxlan_mdb_check_empty, NULL); }
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index f41db72e9229d9cc8460ddbe265c6cd07890032d..f4f519a365f524e1301d769f75690d836b9e4432 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h@@ -301,6 +301,7 @@ struct vxlan_dev { spinlock_t hash_lock; unsigned int addrcnt; struct gro_cells gro_cells; + unsigned long flags; struct vxlan_config cfg;
@@ -314,6 +315,10 @@ struct vxlan_dev { unsigned int mdb_seq; }; +enum vxlan_dev_flags { + VXLAN_DEV_F_MDB, +}; + #define VXLAN_F_LEARN 0x01 #define VXLAN_F_PROXY 0x02 #define VXLAN_F_RSC 0x04
@@ -332,7 +337,6 @@ struct vxlan_dev { #define VXLAN_F_IPV6_LINKLOCAL 0x8000 #define VXLAN_F_TTL_INHERIT 0x10000 #define VXLAN_F_VNIFILTER 0x20000 -#define VXLAN_F_MDB 0x40000 #define VXLAN_F_LOCALBYPASS 0x80000 #define VXLAN_F_MC_ROUTE 0x100000
--
2.55.0.970.g62bdec98f9-goog