On Mon, Jun 26, 2023 at 07:50:44PM +0530, Praveen Kumar wrote:
> On 6/26/2023 2:48 PM, souradeep chakrabarti wrote:
> > From: Souradeep Chakrabarti <schakrabarti@xxxxxxxxxxxxxxxxxxx>
> >
> > This patch addresses the VF unload issue, where mana_dealloc_queues()
> > gets stuck in infinite while loop, because of host unresponsiveness.
> > It adds a timeout in the while loop, to fix it.
> >
> > Fixes: ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f (net: mana: Add a driver for
> > Microsoft Azure Network Adapter)
> > Signed-off-by: Souradeep Chakrabarti <schakrabarti@xxxxxxxxxxxxxxxxxxx>
> > ---
> > V2 -> V3:
> > * Splitted the patch in two parts.
> > * Removed the unnecessary braces from mana_dealloc_queues().
> > ---
> > drivers/net/ethernet/microsoft/mana/mana_en.c | 19 +++++++++++++++++--
> > 1 file changed, 17 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
> > index d907727c7b7a..cb5c43c3c47e 100644
> > --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> > +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> > @@ -2329,7 +2329,10 @@ static int mana_dealloc_queues(struct net_device *ndev)
> > {
> > struct mana_port_context *apc = netdev_priv(ndev);
> > struct gdma_dev *gd = apc->ac->gdma_dev;
> > + unsigned long timeout;
> > struct mana_txq *txq;
> > + struct sk_buff *skb;
> > + struct mana_cq *cq;
> > int i, err;
> >
> > if (apc->port_is_up)
> > @@ -2348,13 +2351,25 @@ static int mana_dealloc_queues(struct net_device *ndev)
> > *
> > * Drain all the in-flight TX packets
> > */
> > +
> > + timeout = jiffies + 120 * HZ;
> > for (i = 0; i < apc->num_queues; i++) {
> > txq = &apc->tx_qp[i].txq;
> > -
> > - while (atomic_read(&txq->pending_sends) > 0)
> > + while (atomic_read(&txq->pending_sends) > 0 &&
> > + time_before(jiffies, timeout))
> > usleep_range(1000, 2000);
> > }
> >
> > + for (i = 0; i < apc->num_queues; i++) {
> > + txq = &apc->tx_qp[i].txq;
> > + cq = &apc->tx_qp[i].tx_cq;
> > + while (atomic_read(&txq->pending_sends)) {
> > + skb = skb_dequeue(&txq->pending_skbs);
> > + mana_unmap_skb(skb, apc);
> > + napi_consume_skb(skb, cq->budget);
> > + atomic_sub(1, &txq->pending_sends);
> > + }
> > + }
>
> Can we combine these 2 loops into 1 something like this ?
>
> for (i = 0; i < apc->num_queues; i++) {
> txq = &apc->tx_qp[i].txq;
> cq = &apc->tx_qp[i].tx_cq;
> while (atomic_read(&txq->pending_sends)) {
> if (time_before(jiffies, timeout)) {
> usleep_range(1000, 2000);
> } else {
> skb = skb_dequeue(&txq->pending_skbs);
> mana_unmap_skb(skb, apc);
> napi_consume_skb(skb, cq->budget);
> atomic_sub(1, &txq->pending_sends);
> }
> }
> }
We should free up the skbs only after timeout has happened or after all the
queues are looped.
> > /* We're 100% sure the queues can no longer be woken up, because
> > * we're sure now mana_poll_tx_cq() can't be running.
> > */
