iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

net: make for_each_netdev_dump() a little more bug-proof

Browse Source 
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 <kuba@kernel.org>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2024-06-13 14:33:16 -07:00 committed by David S. Miller
parent 69776921e8
commit f22b4b55ed
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/netdevice.h
View File

@ -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)
{