Tony Nguyen says:
====================
Fix i40e/ice/iavf VF bonding after netdev lock changes
Jose Ignacio Tornos Martinez says:
This series fixes VF bonding failures introduced by commit ad7c7b2172
("net: hold netdev instance lock during sysfs operations").
When adding VFs to a bond immediately after setting trust mode, MAC
address changes fail with -EAGAIN, preventing bonding setup. This
affects both i40e (700-series) and ice (800-series) Intel NICs.
The core issue is lock contention: iavf_set_mac() is now called with the
netdev lock held and waits for MAC change completion while holding it.
However, both the watchdog task that sends the request and the adminq_task
that processes PF responses also need this lock, creating a deadlock where
neither can run, causing timeouts.
Additionally, setting VF trust triggers an unnecessary ~10 second VF reset
in i40e driver that delays bonding setup, even though filter
synchronization happens naturally during normal VF operation. For ice
driver, the delay is not so big, but in the same way the operation is not
necessary.
This series:
1. Eliminates unnecessary VF reset when setting trust in i40e (reset only
if revoking trust and VF has advanced features configured).
2. Fixes lock contention by polling admin queue synchronously
3. Eliminates unnecessary VF reset when setting trust in ice, (reset only
if revoking trust and VF has advanced features configured).
The key fix (patch 2/3) implements a synchronous MAC change operation
similar to the approach used for ndo_change_mtu deadlock fix:
https://lore.kernel.org/20260211191855.1532226-1-poros@redhat.com
Instead of scheduling work and waiting, it:
- Sends the virtchnl message directly (not via watchdog)
- Polls the admin queue hardware directly for responses
- Processes all messages inline (including non-MAC messages)
- Returns when complete or times out
This allows the operation to complete synchronously while holding
netdev_lock, without relying on watchdog or adminq_task.
The function can sleep for up to 2.5 seconds polling hardware, but this
is acceptable since netdev_lock is per-device and only serializes
operations on the same interface.
Testing shows VF bonding now works reliably in ~5 seconds vs 15+ seconds
before (i40e), without timeouts or errors (i40e and ice).
Tested on Intel 700-series (i40e) and 800-series (ice) dual-port NICs
with iavf driver.
Thanks to Jan Tluka <jtluka@redhat.com> and Yuying Ma <yuma@redhat.com> for
reporting the issues.
* '40GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue:
ice: skip unnecessary VF reset when setting trust
iavf: send MAC change request synchronously
i40e: skip unnecessary VF reset when setting trust
====================
Link: https://patch.msgid.link/20260928224454.483072-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
af7886fcfb