[PATCH net-next] ibmvnic: fix rx buffer tracking and index management in replenish_rx_pool partial success

[PATCH net-next] ibmvnic: fix rx buffer tracking and index management in replenish_rx_pool partial success

[Dany Madden]

From: "Dwip N. Banerjee" <dnbanerg@us.ibm.com>

We observed that in the error case for batched send_subcrq_indirect() the
driver does not account for the partial success case. This caused Linux to
crash when free_map and pool index are inconsistent.

Driver needs to update the rx pools "available" count when some batched
sends worked but an error was encountered as part of the whole operation.
Also track replenish_add_buff_failure for statistic purposes.

Fixes: 4f0b6812e9b9a ("ibmvnic: Introduce batched RX buffer descriptor transmission")
Signed-off-by: Dwip N. Banerjee <dnbanerg@us.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index cb701a6c0712..a2191392ca4f 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -398,6 +398,8 @@ static void replenish_rx_pool(struct ibmvnic_adapter *adapter,
 		dev_kfree_skb_any(pool->rx_buff[index].skb);
 		pool->rx_buff[index].skb = NULL;
 	}
+	adapter->replenish_add_buff_failure += ind_bufp->index;
+	atomic_add(buffers_added, &pool->available);
 	ind_bufp->index = 0;
 	if (lpar_rc == H_CLOSED || adapter->failover_pending) {
 		/* Disable buffer pool replenishment and report carrier off if
-- 
2.18.2

Re: [PATCH net-next] ibmvnic: fix rx buffer tracking and index management in replenish_rx_pool partial success

[David Miller]

From: Dany Madden <drt@linux.ibm.com>
Date: Wed,  9 Dec 2020 20:53:31 -0500

> From: "Dwip N. Banerjee" <dnbanerg@us.ibm.com>
> 
> We observed that in the error case for batched send_subcrq_indirect() the
> driver does not account for the partial success case. This caused Linux to
> crash when free_map and pool index are inconsistent.
> 
> Driver needs to update the rx pools "available" count when some batched
> sends worked but an error was encountered as part of the whole operation.
> Also track replenish_add_buff_failure for statistic purposes.
> 
> Fixes: 4f0b6812e9b9a ("ibmvnic: Introduce batched RX buffer descriptor transmission")
> Signed-off-by: Dwip N. Banerjee <dnbanerg@us.ibm.com>
> Reviewed-by: Dany Madden <drt@linux.ibm.com>

Applied, thanks.