netdev - [PATCH net 2/2] ibmvnic: Free any outstanding tx skbs during scrq reset

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Message-Id: <20240620152312.1032323-3-nnac123@linux.ibm.com>
Date: Thu, 20 Jun 2024 10:23:12 -0500
From: Nick Child <nnac123@...ux.ibm.com>
To: netdev@...r.kernel.org
Cc: nick.child@....com, haren@...ux.ibm.com, ricklind@...ibm.com,
        Nick Child <nnac123@...ux.ibm.com>
Subject: [PATCH net 2/2] ibmvnic: Free any outstanding tx skbs during scrq reset

There are 2 types of outstanding tx skb's:
Type 1: Packets that are sitting in the drivers ind_buff that are
waiting to be batch sent to the NIC. During a device reset, these are
freed with a call to ibmvnic_tx_scrq_clean_buffer()
Type 2: Packets that have been sent to the NIC and are awaiting a TX
completion IRQ. These are free'd during a reset with a call to
clean_tx_pools()

During any reset which requires us to free the tx irq, ensure that the
Type 2 skb references are freed. Since the irq is released, it is
impossible for the NIC to inform of any completions.

Furthermore, later in the reset process is a call to init_tx_pools()
which marks every entry in the tx pool as free (ie not outstanding).
So if the driver is to make a call to init_tx_pools(), it must first
be sure that the tx pool is empty of skb references.

This issue was discovered by observing the following in the logs during
EEH testing:
	TX free map points to untracked skb (tso_pool 0 idx=4)
	TX free map points to untracked skb (tso_pool 0 idx=5)
	TX free map points to untracked skb (tso_pool 1 idx=36)

Fixes: 65d6470d139a ("ibmvnic: clean pending indirect buffs during reset")
Signed-off-by: Nick Child <nnac123@...ux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 887d92a88403..23ebeb143987 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -4073,6 +4073,12 @@ static void release_sub_crqs(struct ibmvnic_adapter *adapter, bool do_h_free)
 		adapter->num_active_tx_scrqs = 0;
 	}

+	/* Clean any remaining outstanding SKBs
+	 * we freed the irq so we won't be hearing
+	 * from them
+	 */
+	clean_tx_pools(adapter);
+
 	if (adapter->rx_scrq) {
 		for (i = 0; i < adapter->num_active_rx_scrqs; i++) {
 			if (!adapter->rx_scrq[i])
-- 
2.39.3