Commit a7dfeda6 authored by Souradeep Chakrabarti's avatar Souradeep Chakrabarti Committed by Jakub Kicinski
Browse files

net: mana: Fix MANA VF unload when hardware is unresponsive 



When unloading the MANA driver, mana_dealloc_queues() waits for the MANA
hardware to complete any inflight packets and set the pending send count
to zero. But if the hardware has failed, mana_dealloc_queues()
could wait forever.

Fix this by adding a timeout to the wait. Set the timeout to 120 seconds,
which is a somewhat arbitrary value that is more than long enough for
functional hardware to complete any sends.

Cc: stable@vger.kernel.org
Fixes: ca9c54d2 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: default avatarSouradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Link: https://lore.kernel.org/r/1691576525-24271-1-git-send-email-schakrabarti@linux.microsoft.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 048c796b

drivers/net/ethernet/microsoft/mana/mana_en.c

+33 −4
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/ethtool.h>

#include <linux/filter.h>

#include <linux/mm.h>

#include <linux/pci.h>



#include <net/checksum.h>

#include <net/ip6_checksum.h>
@@ -2345,9 +2346,12 @@ int mana_attach(struct net_device *ndev) 
static int mana_dealloc_queues(struct net_device *ndev)

{

	struct mana_port_context *apc = netdev_priv(ndev);

	unsigned long timeout = jiffies + 120 * HZ;

	struct gdma_dev *gd = apc->ac->gdma_dev;

	struct mana_txq *txq;

	struct sk_buff *skb;

	int i, err;

	u32 tsleep;



	if (apc->port_is_up)

		return -EINVAL;
@@ -2363,15 +2367,40 @@ static int mana_dealloc_queues(struct net_device *ndev) 
	 * to false, but it doesn't matter since mana_start_xmit() drops any

	 * new packets due to apc->port_is_up being false.

	 *

	 * Drain all the in-flight TX packets

	 * Drain all the in-flight TX packets.

	 * A timeout of 120 seconds for all the queues is used.

	 * This will break the while loop when h/w is not responding.

	 * This value of 120 has been decided here considering max

	 * number of queues.

	 */



	for (i = 0; i < apc->num_queues; i++) {

		txq = &apc->tx_qp[i].txq;



		while (atomic_read(&txq->pending_sends) > 0)

			usleep_range(1000, 2000);

		tsleep = 1000;

		while (atomic_read(&txq->pending_sends) > 0 &&

		       time_before(jiffies, timeout)) {

			usleep_range(tsleep, tsleep + 1000);

			tsleep <<= 1;

		}

		if (atomic_read(&txq->pending_sends)) {

			err = pcie_flr(to_pci_dev(gd->gdma_context->dev));

			if (err) {

				netdev_err(ndev, "flr failed %d with %d pkts pending in txq %u\n",

					   err, atomic_read(&txq->pending_sends),

					   txq->gdma_txq_id);

			}

			break;

		}

	}



	for (i = 0; i < apc->num_queues; i++) {

		txq = &apc->tx_qp[i].txq;

		while ((skb = skb_dequeue(&txq->pending_skbs))) {

			mana_unmap_skb(skb, apc);

			dev_kfree_skb_any(skb);

		}

		atomic_set(&txq->pending_sends, 0);

	}

	/* 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.

	 */