This can be used to selectively disable feature flags for checksum offload,
scatter/gather or GSO by changing vif->netdev_features.
Removing features from vif->netdev_features does not affect the netdev
features themselves, but instead fixes up skbs in the tx path so that the
offloads are not needed in the driver.

Aside from making it easier to deal with vif type based hardware limitations,
this also makes it possible to optimize performance on hardware without native
GSO support by declaring GSO support in hw->netdev_features and removing it
from vif->netdev_features. This allows mac80211 to handle GSO segmentation
after the sta lookup, but before itxq enqueue, thus reducing the number of
unnecessary sta lookups, as well as some other per-packet processing.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20221010094338.78070-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Start to align the TX handling to only use internal TX queues (iTXQs):

Provide a handler for drivers not having a custom wake_tx_queue
callback and update the documentation.

Signed-off-by: Alexander Wetzel <alexander@wetzel-home.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

We might sometimes need to use RCU and locking in the same code
path, so add the two variants link_conf_dereference_check() and
link_sta_dereference_check().

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Create debugfs data per-link. For drivers, there is a new operation
link_sta_add_debugfs which will always be called.

For non-MLO, the station directory will be used directly rather than
creating a corresponding subdirectory. As such, non-MLO drivers can
simply continue to create the data from sta_debugfs_add.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
[add missing inlines if !CONFIG_MAC80211_DEBUGFS]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

While often not needed, this considerably simplifies going from a link
to the STA. This helps in cases such as debugfs where a single pointer
should allow accessing a specific link and the STA.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Implement an API function and debugfs file to switch
active links.

Also provide an async version of the API so drivers
can call it in arbitrary contexts, e.g. while in the
authorized callback.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The A-MSDU data needs to be stored per-link and aggregated into a single
value for the station. Add a new struct ieee_80211_sta_aggregates in
order to store this data and a new function
ieee80211_sta_recalc_aggregates to update the current data for the STA.

Note that in the non MLO case the pointer in ieee80211_sta will directly
reference the data in deflink.agg, which means that recalculation may be
skipped in that case.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Add macros (and an exported function) to allow checking some
link RCU protected accesses that are happening in callbacks
from mac80211 and are thus under the correct lock.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Add a link_id parameter to ieee80211_nullfunc_get() to be
able to obtain a correctly addressed frame.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Add a new API function ieee80211_find_sta_by_link_addrs()
that looks up the STA and link ID based on interface and
station link addresses.

We're going to use it for mac80211-hwsim to track on the
AP side which links are active.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>