From f22b4b55edb507a2b30981e133b66b642be4d13f Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Thu, 13 Jun 2024 14:33:16 -0700 Subject: [PATCH] net: make for_each_netdev_dump() a little more bug-proof I find the behavior of xa_for_each_start() slightly counter-intuitive. It doesn't end the iteration by making the index point after the last element. IOW calling xa_for_each_start() again after it "finished" will run the body of the loop for the last valid element, instead of doing nothing. This works fine for netlink dumps if they terminate correctly (i.e. coalesce or carefully handle NLM_DONE), but as we keep getting reminded legacy dumps are unlikely to go away. Fixing this generically at the xa_for_each_start() level seems hard - there is no index reserved for "end of iteration". ifindexes are 31b wide, tho, and iterator is ulong so for for_each_netdev_dump() it's safe to go to the next element. Signed-off-by: Jakub Kicinski Reviewed-by: Przemek Kitszel Signed-off-by: David S. Miller --- include/linux/netdevice.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index f148a01dd1d1..85111502cf8f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3021,7 +3021,8 @@ int call_netdevice_notifiers_info(unsigned long val, #define net_device_entry(lh) list_entry(lh, struct net_device, dev_list) #define for_each_netdev_dump(net, d, ifindex) \ - xa_for_each_start(&(net)->dev_by_index, (ifindex), (d), (ifindex)) + for (; (d = xa_find(&(net)->dev_by_index, &ifindex, \ + ULONG_MAX, XA_PRESENT)); ifindex++) static inline struct net_device *next_net_device(struct net_device *dev) {