This switches the airtime scheduler in mac80211 to use a virtual
time-based scheduler instead of the round-robin scheduler used before.
This has a couple of advantages:

- No need to sync up the round-robin scheduler in firmware/hardware with
  the round-robin airtime scheduler.

- If several stations are eligible for transmission we can schedule both
  of them; no need to hard-block the scheduling rotation until the head
  of the queue has used up its quantum.

- The check of whether a station is eligible for transmission becomes
  simpler (in ieee80211_txq_may_transmit()).

The drawback is that scheduling becomes slightly more expensive, as we
need to maintain an rbtree of TXQs sorted by virtual time. This means
that ieee80211_register_airtime() becomes O(logN) in the number of
currently scheduled TXQs because it can change the order of the
scheduled stations. We mitigate this overhead by only resorting when a
station changes position in the tree, and hopefully N rarely grows too
big (it's only TXQs currently backlogged, not all associated stations),
so it shouldn't be too big of an issue.

To prevent divisions in the fast path, we maintain both station sums and
pre-computed reciprocals of the sums. This turns the fast-path operation
into a multiplication, with divisions only happening as the number of
active stations change (to re-compute the current sum of all active
station weights). To prevent this re-computation of the reciprocal from
happening too frequently, we use a time-based notion of station
activity, instead of updating the weight every time a station gets
scheduled or de-scheduled. As queues can oscillate between empty and
occupied quite frequently, this can significantly cut down on the number
of re-computations. It also has the added benefit of making the station
airtime calculation independent on whether the queue happened to have
drained at the time an airtime value was accounted.

Co-developed-by: Yibo Zhao <yiboz@codeaurora.org>
Signed-off-by: Yibo Zhao <yiboz@codeaurora.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20210623134755.235545-1-toke@redhat.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

When reconfiguration fails, we shut down everything, but we
cannot call cfg80211_shutdown_all_interfaces() with the wiphy
mutex held. Since cfg80211 now calls it on resume errors, we
only need to do likewise for where we call reconfig (whether
directly or indirectly), but not under the wiphy lock.

Cc: stable@vger.kernel.org
Fixes: 2fe8ef106238 ("cfg80211: change netdev registration/unregistration semantics")
Link: https://lore.kernel.org/r/20210608113226.78233c80f548.Iecc104aceb89f0568f50e9670a9cb191a1c8887b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

cfg80211 now calls suspend/resume with the wiphy lock
held, and while there's a problem with that needing
to be fixed, we should do the same in debugfs.

Cc: stable@vger.kernel.org
Fixes: a05829a7222e ("cfg80211: avoid holding the RTNL when calling the driver")
Link: https://lore.kernel.org/r/20210608113226.14020430e449.I78e19db0a55a8295a376e15ac4cf77dbb4c6fb51@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Some HW/driver can support passing ethernet rx decap frames and
raw 802.11 frames for the monitor interface concurrently and
via separate RX calls to mac80211. Packets going to the monitor
interface(s) would be in 802.11 format and thus not have the
RX_FLAG_8023 set, and 802.11 format monitoring frames should have
RX_FLAG_ONLY_MONITOR set.

Drivers doing such can enable the SUPPORTS_CONC_MON_RX_DECAP to
allow using ethernet decap offload while a monitor interface is
active, currently RX decapsulation offload gets disabled when a
monitor interface is added.

Signed-off-by: Sriram R <srirrama@codeaurora.org>
Link: https://lore.kernel.org/r/1617068116-32253-1-git-send-email-srirrama@codeaurora.org
[add proper documentation, rewrite commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Introduce aql_enable node in debugfs in order to enable/disable aql.
This is useful for debugging purpose.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/e7a934d5d84e4796c4f97ea5de4e66c824296b07.1610214851.git.lorenzo@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This allows drivers to pass 802.3 frames to mac80211, with some restrictions:

- the skb must be passed with a valid sta
- fast-rx needs to be active for the sta
- monitor mode needs to be disabled

mac80211 will tell the driver when it is safe to enable rx decap offload for
a particular station.

In order to implement support, a driver must:

- call ieee80211_hw_set(hw, SUPPORTS_RX_DECAP_OFFLOAD)
- implement ops->sta_set_decap_offload
- mark 802.3 frames with RX_FLAG_8023

If it doesn't want to enable offload for some vif types, it can mask out
IEEE80211_OFFLOAD_DECAP_ENABLED in vif->offload_flags from within the
.add_interface or .update_vif_offload driver ops

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20201218184718.93650-6-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This fixes strlen mismatch problems happening in some .write callbacks
of debugfs.

When trying to configure airtime_flags in debugfs, an error appeared:
ash: write error: Invalid argument

The error is returned from kstrtou16() since a wrong length makes it
miss the real end of input string.  To fix this, use count as the string
length, and set proper end of string for a char buffer.

The debug print is shown - airtime_flags_write: count = 2, len = 8,
where the actual length is 2, but "len = strlen(buf)" gets 8.

Also cleanup the other similar cases for the sake of consistency.

Signed-off-by: Sujuan Chen <sujuan.chen@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://lore.kernel.org/r/20210112032028.7482-1-shayne.chen@mediatek.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The macro uses should have (and already have) the semicolon.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20201127193842.2876355-1-trix@redhat.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The current API (which lets the driver turn on/off per vif directly) has a
number of limitations:
- it does not deal with AP_VLAN
- conditions for enabling (no tkip, no monitor) are only checked at
  add_interface time
- no way to indicate 4-addr support

In order to address this, store offload flags in struct ieee80211_vif
(easy to extend for decap offload later). mac80211 initially sets the enable
flag, but gives the driver a chance to modify it before its settings are
applied. In addition to the .add_interface op, a .update_vif_offload op is
introduced, which can be used for runtime changes.

If a driver can't disable encap offload at runtime, or if it has some extra
limitations, it can simply override the flags within those ops.

Support for encap offload with 4-address mode interfaces can be enabled
by setting a flag from .add_interface or .update_vif_offload.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20200908123702.88454-6-nbd@nbd.name
[resolved conflict with commit aa2092a9bab3 ("ath11k: add raw mode and
software crypto support")]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Improve airtime_flags debugfs handler readability reporting configured
airtime flags in both numeric and human readable manner

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/9df7e40b45e95bb0b320317831455beaed1ee3ee.1574872357.git.lorenzo@kernel.org
[remove AQL since it's no longer there]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>