linux.git/net/core/dev_addr_lists.c, branch v7.1

net: warn ops-locked drivers still using ndo_set_rx_mode

2026-04-21T10:50:25+00:00

Now that all in-tree ops-locked drivers have been converted to
ndo_set_rx_mode_async, add a warning in register_netdevice to catch
any remaining or newly added drivers that use ndo_set_rx_mode with
ops locking. This ensures future driver authors are guided toward
the async path.

Also route ops-locked devices through netdev_rx_mode_work even if they
lack rx_mode NDOs, to ensure netdev_ops_assert_locked() does not fire
on the legacy path where only RTNL is held.

Reviewed-by: Aleksandr Loktionov 
Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260416185712.2155425-14-sdf@fomichev.me
Signed-off-by: Paolo Abeni

net: move promiscuity handling into netdev_rx_mode_work

2026-04-21T10:50:24+00:00

Move unicast promiscuity tracking into netdev_rx_mode_work so it runs
under netdev_ops_lock instead of under the addr_lock spinlock. This
is required because __dev_set_promiscuity calls dev_change_rx_flags
and __dev_notify_flags, both of which may need to sleep.

Change ASSERT_RTNL() to netdev_ops_assert_locked() in
__dev_set_promiscuity, netif_set_allmulti and __dev_change_flags
since these are now called from the work queue under the ops lock.

Link: https://lore.kernel.org/netdev/20260214033859.43857-1-jiayuan.chen@linux.dev/
Fixes: 78cd408356fe ("net: add missing instance lock to dev_set_promiscuity")
Reported-by: syzbot+2b3391f44313b3983e91@syzkaller.appspotmail.com
Reviewed-by: Aleksandr Loktionov 
Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260416185712.2155425-5-sdf@fomichev.me
Signed-off-by: Paolo Abeni

net: cache snapshot entries for ndo_set_rx_mode_async

2026-04-21T10:50:13+00:00

Add a per-device netdev_hw_addr_list cache (rx_mode_addr_cache) that
allows __hw_addr_list_snapshot() and __hw_addr_list_reconcile() to
reuse previously allocated entries instead of hitting GFP_ATOMIC on
every snapshot cycle.

snapshot pops entries from the cache when available, falling back to
__hw_addr_create(). reconcile splices both snapshot lists back into
the cache via __hw_addr_splice(). The cache is flushed in
free_netdev().

Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260416185712.2155425-4-sdf@fomichev.me
Signed-off-by: Paolo Abeni

net: introduce ndo_set_rx_mode_async and netdev_rx_mode_work

2026-04-21T10:50:03+00:00

Add ndo_set_rx_mode_async callback that drivers can implement instead
of the legacy ndo_set_rx_mode. The legacy callback runs under the
netif_addr_lock spinlock with BHs disabled, preventing drivers from
sleeping. The async variant runs from a work queue with rtnl_lock and
netdev_lock_ops held, in fully sleepable context.

When __dev_set_rx_mode() sees ndo_set_rx_mode_async, it schedules
netdev_rx_mode_work instead of calling the driver inline. The work
function takes two snapshots of each address list (uc/mc) under
the addr_lock, then drops the lock and calls the driver with the
work copies. After the driver returns, it reconciles the snapshots
back to the real lists under the lock.

Add netif_rx_mode_sync() to opportunistically execute the pending
workqueue update inline, so that rx mode changes are committed
before returning to userspace:
  - dev_change_flags (SIOCSIFFLAGS / RTM_NEWLINK)
  - dev_set_promiscuity
  - dev_set_allmulti
  - dev_ifsioc SIOCADDMULTI / SIOCDELMULTI
  - do_setlink (RTM_SETLINK)

Note that some deep hierarchies still do skip the lower updates via:
  - dev_uc_sync
  - dev_mc_sync

If we do end up hitting user-visible issues, we can add more calls to
netif_rx_mode_sync in specific places. But hopefully we should not,
the actual user-visible lists are still synced, it's that just HW state
that might be lagging.

Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260416185712.2155425-3-sdf@fomichev.me
Signed-off-by: Paolo Abeni

net: add address list snapshot and reconciliation infrastructure

2026-04-21T10:50:03+00:00

Introduce __hw_addr_list_snapshot() and __hw_addr_list_reconcile()
for use by the upcoming ndo_set_rx_mode_async callback.

The async rx_mode path needs to snapshot the device's unicast and
multicast address lists under the addr_lock, hand those snapshots
to the driver (which may sleep), and then propagate any sync_cnt
changes back to the real lists. Two identical snapshots are taken:
a work copy for the driver to pass to __hw_addr_sync_dev() and a
reference copy to compute deltas against.

__hw_addr_list_reconcile() walks the reference snapshot comparing
each entry against the work snapshot to determine what the driver
synced or unsynced. It then applies those deltas to the real list,
handling concurrent modifications:

  - If the real entry was concurrently removed but the driver synced
    it to hardware (delta > 0), re-insert a stale entry so the next
    work run properly unsyncs it from hardware.
  - If the entry still exists, apply the delta normally. An entry
    whose refcount drops to zero is removed.

  # dev_addr_test_snapshot_benchmark: 1024 addrs x 1000 snapshots: 89872802 ns total, 89872 ns/iter
  # dev_addr_test_snapshot_benchmark.speed: slow

Reviewed-by: Aleksandr Loktionov 
Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20260416185712.2155425-2-sdf@fomichev.me
Signed-off-by: Paolo Abeni

net: s/dev_pre_changeaddr_notify/netif_pre_changeaddr_notify/

2025-07-19T00:27:47+00:00

Commit cc34acd577f1 ("docs: net: document new locking reality")
introduced netif_ vs dev_ function semantics: the former expects locked
netdev, the latter takes care of the locking. We don't strictly
follow this semantics on either side, but there are more dev_xxx handlers
now that don't fit. Rename them to netif_xxx where appropriate.

netif_pre_changeaddr_notify is used only by ipvlan/bond, so move it into
NETDEV_INTERNAL namespace.

Signed-off-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250717172333.1288349-4-sdf@fomichev.me
Signed-off-by: Jakub Kicinski

net: ti: icssg-prueth: Add Multicast Filtering support for VLAN in MAC mode

2025-01-14T11:17:27+00:00

Add multicast filtering support for VLAN interfaces in dual EMAC mode
for ICSSG driver.

The driver uses vlan_for_each() API to get the list of available
vlans. The driver then sync mc addr of vlan interface with a locally
mainatined list emac->vlan_mcast_list[vid] using __hw_addr_sync_multiple()
API.

__hw_addr_sync_multiple() is used instead of __hw_addr_sync() to sync
vdev->mc with local list because the sync_cnt for addresses in vdev->mc
will already be set by the vlan_dev_set_rx_mode() [net/8021q/vlan_dev.c]
and __hw_addr_sync() only syncs when the sync_cnt == 0. Whereas
__hw_addr_sync_multiple() can sync addresses even if sync_cnt is not 0.
Export __hw_addr_sync_multiple() so that driver can use it.

Once the local list is synced, driver calls __hw_addr_sync_dev() with
the local list, vdev, sync and unsync callbacks.

__hw_addr_sync_dev() is used with the local maintained list as the list
to synchronize instead of using __dev_mc_sync() on vdev because
__dev_mc_sync() on vdev will call __hw_addr_sync_dev() on vdev->mc and
sync_cnt for addresses in vdev->mc will already be set by the
vlan_dev_set_rx_mode() [net/8021q/vlan_dev.c] and __hw_addr_sync_dev()
only syncs if the sync_cnt of addresses in the list (vdev->mc in this case)
is 0. Whereas __hw_addr_sync_dev() on local list will work fine as the
sync_cnt for addresses in the local list will still be 0.

Based on change in addresses in the local list, sync / unsync callbacks
are invoked. In the sync / unsync API in driver, based on whether the ndev
is vlan or not, driver passes appropriate vid to FDB helper functions.

Signed-off-by: MD Danish Anwar 
Signed-off-by: Paolo Abeni

net: Correct spelling in net/core

2024-08-26T16:37:23+00:00

Correct spelling in net/core.
As reported by codespell.

Signed-off-by: Simon Horman 
Link: https://patch.msgid.link/20240822-net-spell-v1-13-3a98971ce2d2@kernel.org
Signed-off-by: Jakub Kicinski

net: extract a few internals from netdevice.h

2022-04-08T03:32:09+00:00

There's a number of functions and static variables used
under net/core/ but not from the outside. We currently
dump most of them into netdevice.h. That bad for many
reasons:
 - netdevice.h is very cluttered, hard to figure out
   what the APIs are;
 - netdevice.h is very long;
 - we have to touch netdevice.h more which causes expensive
   incremental builds.

Create a header under net/core/ and move some declarations.

The new header is also a bit of a catch-all but that's
fine, if we create more specific headers people will
likely over-think where their declaration fit best.
And end up putting them in netdevice.h, again.

More work should be done on splitting netdevice.h into more
targeted headers, but that'd be more time consuming so small
steps.

Signed-off-by: Jakub Kicinski

dev_addr_list: put the first addr on the tree

2021-11-20T12:25:57+00:00

Since all netdev->dev_addr modifications go via dev_addr_mod()
we can put it on the list. When address is change remove it
and add it back.

Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller