[v5,0/2] mac80211: Trigger disconnect for STA during target hardware restart

Message

Youghandhar Chintala March 8, 2022, 11:53 a.m. UTC

Currently in case of target hardware restart ,we just reconfig and
re-enable the security keys and enable the network queues to start
data traffic back from where it was interrupted.

Many ath10k wifi chipsets have sequence numbers for the data
packets assigned by firmware and the mac sequence number will
restart from zero after target hardware restart leading to mismatch
in the sequence number expected by the remote peer vs the sequence
number of the frame sent by the target firmware.

This mismatch in sequence number will cause out-of-order packets
on the remote peer and all the frames sent by the device are dropped
until we reach the sequence number which was sent before we restarted
the target hardware

In order to fix this, we trigger a disconnect in case of hardware
restart. After this there will be a fresh connection and thereby
avoiding the dropping of frames by remote peer.

The right fix would be to pull the entire data path into the host
which is not feasible or would need lots of complex/inefficient
datapath changes.

---
Changes from v3:
- Fixed commit text errors
- Remove excess space in "hardware  restart"
- Removed blank line between the function description and the arguments

Youghandhar Chintala (2):
  mac80211: Add support to trigger sta disconnect on  hardware restart
  ath10k: Trigger sta disconnect on hardware restart

 drivers/net/wireless/ath/ath10k/core.c | 25 +++++++++++++++++++
 drivers/net/wireless/ath/ath10k/hw.h   |  2 ++
 include/net/mac80211.h                 | 10 ++++++++
 net/mac80211/ieee80211_i.h             |  3 +++
 net/mac80211/mlme.c                    | 12 ++++++++++
 net/mac80211/util.c                    | 33 +++++++++++++++++++++++---
 6 files changed, 82 insertions(+), 3 deletions(-)

Comments

Brian Norris March 8, 2022, 6:13 p.m. UTC | #1

On Tue, Mar 08, 2022 at 05:23:23PM +0530, Youghandhar Chintala wrote:
> Currently in case of target hardware restart ,we just reconfig and
> re-enable the security keys and enable the network queues to start
> data traffic back from where it was interrupted.
> 
> Many ath10k wifi chipsets have sequence numbers for the data
> packets assigned by firmware and the mac sequence number will
> restart from zero after target hardware restart leading to mismatch
> in the sequence number expected by the remote peer vs the sequence
> number of the frame sent by the target firmware.
> 
> This mismatch in sequence number will cause out-of-order packets
> on the remote peer and all the frames sent by the device are dropped
> until we reach the sequence number which was sent before we restarted
> the target hardware
> 
> In order to fix this, we trigger a disconnect in case of hardware
> restart. After this there will be a fresh connection and thereby
> avoiding the dropping of frames by remote peer.
> 
> The right fix would be to pull the entire data path into the host
> which is not feasible or would need lots of complex/inefficient
> datapath changes.
> 
> ---
> Changes from v3:
> - Fixed commit text errors
> - Remove excess space in "hardware  restart"
> - Removed blank line between the function description and the arguments

For whatever it's worth, the series looks good to me:

Reviewed-by: Brian Norris <[e-mail]>