Re: [PATCH net v2 3/4] bnxt: make sure xmit_more + errors does not miss doorbells
From: Michael Chan <michael.chan@broadcom.com>
Date: 2021-08-12 06:51:40
On Wed, Aug 11, 2021 at 2:38 PM Jakub Kicinski [off-list ref] wrote:
quoted hunk ↗ jump to hunk
@@ -396,6 +404,8 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) free_size = bnxt_tx_avail(bp, txr); if (unlikely(free_size < skb_shinfo(skb)->nr_frags + 2)) { netif_tx_stop_queue(txq); + if (net_ratelimit() && txr->kick_pending) + netif_warn(bp, tx_err, dev, "bnxt: ring busy!\n");
I think there is one more problem here. Now that it is possible to get here, we can race with bnxt_tx_int() again here. We can call netif_tx_stop_queue() here after bnxt_tx_int() has already cleaned the entire TX ring. So I think we need to call bnxt_tx_wake_queue() here again if descriptors have become available.
return NETDEV_TX_BUSY;
}Attachments
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