From 06bc6f6ed4ae0246a5e52094d1be90906a1361c7 Mon Sep 17 00:00:00 2001

From: Johannes Berg <johannes.berg@intel.com>

Date: Wed, 4 Jul 2018 23:12:33 +0200

Subject: [PATCH] iwlwifi: mvm: synchronize TID queue removal

Git-commit: 06bc6f6ed4ae0246a5e52094d1be90906a1361c7

Patch-mainline: v5.0-rc1

References: bsc#1051510

When we mark a TID as no longer having a queue, there's no

guarantee the TX path isn't using this txq_id right now,

having accessed it just before we reset the value. To fix

this, add synchronize_net() when we change the TIDs from

having a queue to not having one, so that we can then be

sure that the TX path is no longer accessing that queue.

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

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/net/wireless/intel/iwlwifi/mvm/sta.c | 10 ++++++++++

 1 file changed, 10 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c

index 1887d2b9f185..c2b7bb5d107c 100644

--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c

+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c

@@ -545,6 +545,16 @@ static int iwl_mvm_remove_sta_queue_marking(struct iwl_mvm *mvm, int queue)

 	rcu_read_unlock();

+	/*

+	 * The TX path may have been using this TXQ_ID from the tid_data,

+	 * so make sure it's no longer running so that we can safely reuse

+	 * this TXQ later. We've set all the TIDs to IWL_MVM_INVALID_QUEUE

+	 * above, but nothing guarantees we've stopped using them. Thus,

+	 * without this, we could get to iwl_mvm_disable_txq() and remove

+	 * the queue while still sending frames to it.

+	 */

+	synchronize_net();

+

 	return disable_agg_tids;

 }

-- 

2.16.4