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

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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: ca9c54d2d6 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Link: https://lore.kernel.org/r/1691576525-24271-1-git-send-email-schakrabarti@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Souradeep Chakrabarti 2023-08-09 03:22:05 -07:00 committed by Jakub Kicinski
parent 048c796beb
commit a7dfeda6fd
1 changed files with 33 additions and 4 deletions
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37
drivers/net/ethernet/microsoft/mana/mana_en.c
View file

@ -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.
*/