vxlan: vnifilter: use list_for_each_entry_rcu() in vxlan_vnifilter_dump_dev()

RTM_GETTUNNEL dumps currently run under RTNL lock, but
vxlan_vnifilter_dump() also acquires rcu_read_lock().

1) Currently vxlan_vnifilter_dump_dev() traverses vg->vni_list using
   list_for_each_entry_safe(). Even though RTNL is held today, writers
   modify vg->vni_list with list_add_rcu() and list_del_rcu().
   Switch to list_for_each_entry_rcu() for proper RCU traversal and
   as preparation for future lockless dump support.

2) During a paginated dump, RTNL is released between dump skbs.
   If vxlan_vnifilter_dump_dev() returns early because VXLAN_F_VNIFILTER
   is not set or vg has no VNIs, cb->args[1] was not cleared. This leaked
   a non-zero VNI offset to subsequent devices, silently skipping their
   first N VNIs.
   Furthermore, if devices are added or removed between dump calls,
   ordinal device indexes can shift. Track the current device ifindex
   in cb->args[2] and reset cb->args[1] if the device changes.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260922181102.3989489-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions