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Message-Id: <1688544973-2507-1-git-send-email-schakrabarti@linux.microsoft.com>
Date: Wed, 5 Jul 2023 01:16:13 -0700
From: Souradeep Chakrabarti <schakrabarti@...ux.microsoft.com>
To: kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org,
decui@...rosoft.com, davem@...emloft.net, edumazet@...gle.com,
kuba@...nel.org, pabeni@...hat.com, longli@...rosoft.com,
sharmaajay@...rosoft.com, leon@...nel.org, cai.huoqing@...ux.dev,
ssengar@...ux.microsoft.com, vkuznets@...hat.com,
tglx@...utronix.de, linux-hyperv@...r.kernel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-rdma@...r.kernel.org
Cc: stable@...r.kernel.org, schakrabarti@...rosoft.com,
Souradeep Chakrabarti <schakrabarti@...ux.microsoft.com>
Subject: [PATCH V5 net] 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.
Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
---
V4 -> V5:
* Added fixes tag
* Changed the usleep_range from static to incremental value.
* Initialized timeout in the begining.
---
Signed-off-by: Souradeep Chakrabarti <schakrabarti@...ux.microsoft.com>
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 30 ++++++++++++++++---
1 file changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index a499e460594b..56b7074db1a2 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -2345,9 +2345,13 @@ 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;
+ struct mana_cq *cq;
int i, err;
+ u32 tsleep;
if (apc->port_is_up)
return -EINVAL;
@@ -2363,15 +2367,33 @@ 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 << 1);
+ tsleep <<= 1;
+ }
}
+ 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);
+ dev_consume_skb_any(skb);
+ atomic_sub(1, &txq->pending_sends);
+ }
+ }
/* 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.
*/
--
2.34.1
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