Re: [PATCH net] bnxt_en: Fix potential race condition in bnxt_tx_enable()

On Fri, Jul 15, 2016 at 11:20 PM, David Miller [off-list ref] wrote:

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Fri, 15 Jul 2016 16:42:01 -0700

quoted

@@ -4599,7 +4599,9 @@ static void bnxt_tx_enable(struct bnxt *bp)
      for (i = 0; i < bp->tx_nr_rings; i++) {
              txr = &bp->tx_ring[i];
              txq = netdev_get_tx_queue(bp->dev, i);
+             __netif_tx_lock(txq, smp_processor_id());
              txr->dev_state = 0;
+             __netif_tx_unlock(txq);

You're going to have to explain how this could possibly cause a
problem, because I'm pretty sure it can't.

Either the reader sees 0, or non-zero, in this value.

And adding locking around this assignment does not change that at all.

Florian, I agree with David.  The lock is not needed.  The lock in
bnxt_tx_disable() is also unnecessary and should be removed.  Thanks.