netdev - [PATCH net 2/5] ibmvnic: Zero used TX descriptor counter on reset

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Date:   Fri,  6 Apr 2018 18:37:03 -0500
From:   Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>
To:     netdev@...r.kernel.org
Cc:     jallen@...ux.vnet.ibm.com, nfont@...ux.vnet.ibm.com,
        Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>
Subject: [PATCH net 2/5] ibmvnic: Zero used TX descriptor counter on reset

The counter that tracks used TX descriptors pending completion
needs to be zeroed as part of a device reset. This change fixes
a bug causing transmit queues to be stopped unnecessarily and in
some cases a transmit queue stall and timeout reset. If the counter
is not reset, the remaining descriptors will not be "removed",
effectively reducing queue capacity. If the queue is over half full,
it will cause the queue to stall if stopped.

Signed-off-by: Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 58e0143..153a868 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2361,6 +2361,7 @@ static int reset_one_sub_crq_queue(struct ibmvnic_adapter *adapter,
 	}

 	memset(scrq->msgs, 0, 4 * PAGE_SIZE);
+	atomic_set(&scrq->used, 0);
 	scrq->cur = 0;

 	rc = h_reg_sub_crq(adapter->vdev->unit_address, scrq->msg_token,
-- 
1.8.3.1