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 <[email protected]>
---
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
On Wed, 2023-07-05 at 01:16 -0700, Souradeep Chakrabarti 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.
>
> 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 <[email protected]>
the changelog should come after the SoB tag, and there should be no '--
- ' separator before the SoB.
Please double-check your patch with the checkpatch script before the
next submission, it should catch trivial issues as the above one.
> ---
> 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;
The above variable is unused, and causes a build warning. Please remove
the assignment and the variable declaration.
Thanks,
Paolo