Hi Johannes,
Thank you for the comments, I'll see if I can apply all of your
suggestions and resubmit.
Alexis
On Thu, Mar 16, 2017 at 3:18 AM, Johannes Berg
<johannes@xxxxxxxxxxxxxxxx> wrote:
> Sorry - this is the other half of my reply that I accidentally deleted
> before sending...
>
>> +static void flush_tx_skbs(struct ieee80211_sub_if_data *sdata)
>> +{
>> + struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
>> + struct mesh_tx_queue *tx_node;
>> +
>> + spin_lock_bh(&ifmsh->mesh_tx_queue_lock);
>> +
>> + /* Note that this check is important because of the two-
>> stage
>> + * way that ieee80211_if_mesh is initialized.
>> + */
>
> I think you should fix that rather than work around it. If this is
> called with iftype != mesh then this is super problematic anyway, since
> ifmsh->tx_queue_len would alias some other variable (there's a union).
>
>> + if (ifmsh->tx_queue_len > 0) {
>> + mhwmp_dbg(sdata, "flushing %d skbs", ifmsh-
>> >tx_queue_len);
>> +
>> + while (!list_empty(&ifmsh->tx_queue.list)) {
>> + tx_node = list_last_entry(&ifmsh-
>> >tx_queue.list,
>> + struct
>> mesh_tx_queue, list);
>> + kfree_skb(tx_node->skb);
>> + list_del(&tx_node->list);
>> + kfree(tx_node);
>> + }
>> + ifmsh->tx_queue_len = 0;
>> + }
>> +
>> + spin_unlock_bh(&ifmsh->mesh_tx_queue_lock);
>> +}
>
> All of this also gets *vastly* simpler if it's just skb_queue_purge()
> :)
>
>> + spin_lock_bh(&ifmsh->mesh_tx_queue_lock);
>> +
>> + list_for_each_entry(tx_node, &ifmsh->tx_queue.list, list) {
>> + ieee80211_tx_skb(sdata, tx_node->skb);
>> + }
>
> I don't think you should hold the lock across _tx_skb(), ISTR problems
> with that - particularly with the STA lock, so this might be OK, but it
> might also cause lock ordering issues. It's easy to avoid anyway, so
> better not to do it.
>
> johannes
