When TVQM is enabled (iwl_mvm_has_new_tx_api() is true), then
queue numbers are just sequentially assigned 0, 1, 2, ...
Prior to TVQM, in DQA, there were some statically allocated
queue numbers:
 * IWL_MVM_DQA_AUX_QUEUE == 1,
 * both IWL_MVM_DQA_INJECT_MONITOR_QUEUE and
   IWL_MVM_DQA_P2P_DEVICE_QUEUE == 2, and
 * IWL_MVM_DQA_AP_PROBE_RESP_QUEUE == 9.

Now, these values are assigned to the members mvm->aux_queue,
mvm->snif_queue, mvm->probe_queue and mvm->p2p_dev_queue by
default. Normally, this doesn't really matter, and if TVQM is
in fact available we override them to the real values after
allocating a queue for use there.

However, this allocation doesn't always happen. For example,
for mvm->p2p_dev_queue (== 2) it only happens when the P2P
Device interface is started, if any. If it's not started, the
value in mvm->p2p_dev_queue remains 2. This wouldn't really
matter all that much if it weren't for iwl_mvm_is_static_queue()
which checks a queue number against one of those four static
numbers.

Now, if no P2P Device or monitor interface is added then queue
2 may be dynamically allocated, yet alias mvm->p2p_dev_queue or
mvm->snif_queue, and thus iwl_mvm_is_static_queue() erroneously
returns true for it. If it then gets full, all interface queues
are stopped, instead of just backpressuring against the one TXQ
that's really the only affected one.

This clearly can lead to issues, as everything is stopped even
if just a single TXQ filled its corresponding HW queue, if it
happens to have an appropriate number (2 or 9, AUX is always
reassigned.) Due to a mac80211 bug, this also led to a situation
in which the queues remained stopped across a deauthentication
and then attempts to connect to a new AP started failing, but
that's fixed separately.

Fix all of this by simply initializing the queue numbers to
the invalid value until they're used, if TVQM is enabled, and
also setting them back to that value when the queues are later
freed again.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210802172232.2e47e623f9e2.I9b0830dafbb68ef35b7b8f0f46160abec02ac7d0@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>