[PATCH V8 net] net: mana: Fix MANA VF unload when hardware is unresponsive
From: Souradeep Chakrabarti <hidden>
Date: 2023-08-09 10:22:28
Also in:
linux-hyperv, linux-rdma, lkml, stable
Subsystem:
hyper-v/azure core and drivers, networking drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Signed-off-by: Souradeep Chakrabarti <redacted>
---
V7 -> V8:
* Replaced dev_consume_skb_any with dev_kfree_skb_any.
* Added extra braces to use assignment as truth value.
V6 -> V7:
* Optimized the while loop for freeing skb.
V5 -> V6:
* Added pcie_flr to reset the pci after timeout.
* Fixed the position of changelog.
* Removed unused variable like cq.
V4 -> V5:
* Added fixes tag
* Changed the usleep_range from static to incremental value.
* Initialized timeout in the begining.
V3 -> V4:
* Removed the unnecessary braces from mana_dealloc_queues().
V2 -> V3:
* Removed the unnecessary braces from mana_dealloc_queues().
V1 -> V2:
* Added net branch
* Removed the typecasting to (struct mana_context*) of void pointer
* Repositioned timeout variable in mana_dealloc_queues()
* Repositioned vf_unload_timeout in mana_context struct, to utilise the
6 bytes hole
---
drivers/net/ethernet/microsoft/mana/mana_en.c | 37 +++++++++++++++++--
1 file changed, 33 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..c2ad0921e893 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c@@ -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. */
--
2.34.1