[V8,net] net: mana: Fix MANA VF unload when hardware is unresponsive
Commit Message
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 <schakrabarti@linux.microsoft.com>
---
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(-)
Comments
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Wed, 9 Aug 2023 03:22:05 -0700 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- [V8,net] net: mana: Fix MANA VF unload when hardware is unresponsive
https://git.kernel.org/netdev/net/c/a7dfeda6fdec
You are awesome, thank you!
@@ -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.
*/