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Commit 37e474ac authored Jun 19, 2017 by Johannes Berg Committed by Luca Coelho Jun 29, 2017

iwlwifi: mvm: fix mac80211 queue tracking



In the driver, we track which hardware queue is associated with
which mac80211 "hw_queue", in order to be able to stop and wake
it. When moving these bitmaps out of the queue_info structures,
the type of the bitmap was erroneously changed from u32 to u8,
presumably in order to save memory.

Turns out that u32 isn't needed, because the highest queue we
can ever tell mac80211 is always < 16, but a u16 definitely is
needed, queues >=8 do happen.

While at it, throw a BUILD_BUG_ON() into the place where we set
the limit (mvm->first_agg_queue) and a warning when it actually
gets put into the bitmap.

The consequence of this bug is that full HW queues associated
with such a too-high mac80211 number never stop higher layer
queues when full, and thus would simply drop all packets that
couldn't be enqueued to the hardware queue.

Fixes: 34e10860 ("iwlwifi: mvm: remove references to queue_info in new TX path")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

parent 275896ab

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -789,7 +789,7 @@ struct iwl_mvm {
		u64 on_time_scan;
		} radio_stats, accu_radio_stats;

		u8 hw_queue_to_mac80211[IWL_MAX_TVQM_QUEUES];
		u16 hw_queue_to_mac80211[IWL_MAX_TVQM_QUEUES];

		struct {
		u8 hw_queue_refcount;

drivers/net/wireless/intel/iwlwifi/mvm/ops.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -602,9 +602,13 @@ iwl_op_mode_mvm_start(struct iwl_trans trans, const struct iwl_cfg cfg,
		if (mvm->cfg->base_params->num_of_queues == 16) {
		mvm->aux_queue = 11;
		mvm->first_agg_queue = 12;
		BUILD_BUG_ON(BITS_PER_BYTE *
		sizeof(mvm->hw_queue_to_mac80211[0]) < 12);
		} else {
		mvm->aux_queue = 15;
		mvm->first_agg_queue = 16;
		BUILD_BUG_ON(BITS_PER_BYTE *
		sizeof(mvm->hw_queue_to_mac80211[0]) < 16);
		}
		} else {
		mvm->aux_queue = IWL_MVM_DQA_AUX_QUEUE;

drivers/net/wireless/intel/iwlwifi/mvm/utils.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -698,7 +698,13 @@ static bool iwl_mvm_update_txq_mapping(struct iwl_mvm *mvm, int queue,
		if (mvm->queue_info[queue].hw_queue_refcount > 0)
		enable_queue = false;

		if (mac80211_queue != IEEE80211_INVAL_HW_QUEUE) {
		WARN(mac80211_queue >=
		BITS_PER_BYTE * sizeof(mvm->hw_queue_to_mac80211[0]),
		"cannot track mac80211 queue %d (queue %d, sta %d, tid %d)\n",
		mac80211_queue, queue, sta_id, tid);
		mvm->hw_queue_to_mac80211[queue] \|= BIT(mac80211_queue);
		}

		mvm->queue_info[queue].hw_queue_refcount++;
		mvm->queue_info[queue].tid_bitmap \|= BIT(tid);