[PATCH net-next] liquidio: Allow RX descriptors to be consumed before disabling NAPI.

[PATCH net-next] liquidio: Allow RX descriptors to be consumed before disabling NAPI.

[Felix Manlunas]

From: Raghu Vatsavayi <raghu.vatsavayi@cavium.com>

Signed-off-by: Raghu Vatsavayi <raghu.vatsavayi@cavium.com>
Acked-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_core.c    | 23 ++++++++++++++++++++
 drivers/net/ethernet/cavium/liquidio/lio_main.c    | 25 +++++++++++++---------
 drivers/net/ethernet/cavium/liquidio/lio_vf_main.c | 23 ++++++++++++--------
 .../net/ethernet/cavium/liquidio/octeon_network.h  |  1 +
 4 files changed, 53 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_core.c b/drivers/net/ethernet/cavium/liquidio/lio_core.c
index e7b6eb8..8e4716a 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_core.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_core.c
@@ -1157,3 +1157,26 @@ int liquidio_change_mtu(struct net_device *netdev, int new_mtu)
 	octeon_free_soft_command(oct, sc);
 	return 0;
 }
+
+int lio_wait_for_clean_oq(struct octeon_device *oct)
+{
+	int retry = 100, pending_pkts = 0;
+	int idx;
+
+	do {
+		pending_pkts = 0;
+
+		for (idx = 0; idx < MAX_OCTEON_OUTPUT_QUEUES(oct); idx++) {
+			if (!(oct->io_qmask.oq & BIT_ULL(idx)))
+				continue;
+			pending_pkts +=
+				atomic_read(&oct->droq[idx]->pkts_pending);
+		}
+
+		if (pending_pkts > 0)
+			schedule_timeout_uninterruptible(1);
+
+	} while (retry-- && pending_pkts);
+
+	return pending_pkts;
+}
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 140085b..345fe6e 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -2240,16 +2240,6 @@ static int liquidio_stop(struct net_device *netdev)
 	struct octeon_device *oct = lio->oct_dev;
 	struct napi_struct *napi, *n;
 
-	if (oct->props[lio->ifidx].napi_enabled) {
-		list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list)
-			napi_disable(napi);
-
-		oct->props[lio->ifidx].napi_enabled = 0;
-
-		if (OCTEON_CN23XX_PF(oct))
-			oct->droq[0]->ops.poll_mode = 0;
-	}
-
 	ifstate_reset(lio, LIO_IFSTATE_RUNNING);
 
 	netif_tx_disable(netdev);
@@ -2275,6 +2265,21 @@ static int liquidio_stop(struct net_device *netdev)
 		lio->ptp_clock = NULL;
 	}
 
+	/* Wait for any pending Rx descriptors */
+	if (lio_wait_for_clean_oq(oct))
+		netif_info(lio, rx_err, lio->netdev,
+			   "Proceeding with stop interface after partial RX desc processing\n");
+
+	if (oct->props[lio->ifidx].napi_enabled == 1) {
+		list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list)
+			napi_disable(napi);
+
+		oct->props[lio->ifidx].napi_enabled = 0;
+
+		if (OCTEON_CN23XX_PF(oct))
+			oct->droq[0]->ops.poll_mode = 0;
+	}
+
 	dev_info(&oct->pci_dev->dev, "%s interface is stopped\n", netdev->name);
 
 	return 0;
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index 3342d64..66655df 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -1281,15 +1281,6 @@ static int liquidio_stop(struct net_device *netdev)
 	/* tell Octeon to stop forwarding packets to host */
 	send_rx_ctrl_cmd(lio, 0);
 
-	if (oct->props[lio->ifidx].napi_enabled) {
-		list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list)
-			napi_disable(napi);
-
-		oct->props[lio->ifidx].napi_enabled = 0;
-
-		oct->droq[0]->ops.poll_mode = 0;
-	}
-
 	netif_info(lio, ifdown, lio->netdev, "Stopping interface!\n");
 	/* Inform that netif carrier is down */
 	lio->intf_open = 0;
@@ -1302,6 +1293,20 @@ static int liquidio_stop(struct net_device *netdev)
 
 	txqs_stop(netdev);
 
+	/* Wait for any pending Rx descriptors */
+	if (lio_wait_for_clean_oq(oct))
+		netif_info(lio, rx_err, lio->netdev,
+			   "Proceeding with stop interface after partial RX desc processing\n");
+
+	if (oct->props[lio->ifidx].napi_enabled == 1) {
+		list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list)
+			napi_disable(napi);
+
+		oct->props[lio->ifidx].napi_enabled = 0;
+
+		oct->droq[0]->ops.poll_mode = 0;
+	}
+
 	dev_info(&oct->pci_dev->dev, "%s interface is stopped\n", netdev->name);
 
 	return 0;
diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_network.h b/drivers/net/ethernet/cavium/liquidio/octeon_network.h
index 76803a5..b7ee2d3 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_network.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_network.h
@@ -190,6 +190,7 @@ irqreturn_t liquidio_msix_intr_handler(int irq __attribute__((unused)),
 
 int octeon_setup_interrupt(struct octeon_device *oct, u32 num_ioqs);
 
+int lio_wait_for_clean_oq(struct octeon_device *oct);
 /**
  * \brief Register ethtool operations
  * @param netdev    pointer to network device

Re: [PATCH net-next] liquidio: Allow RX descriptors to be consumed before disabling NAPI.

[David Miller]

From: Felix Manlunas <felix.manlunas@cavium.com>
Date: Wed, 14 Mar 2018 16:17:47 -0700

> From: Raghu Vatsavayi <raghu.vatsavayi@cavium.com>
> 
> Signed-off-by: Raghu Vatsavayi <raghu.vatsavayi@cavium.com>
> Acked-by: Derek Chickles <derek.chickles@cavium.com>
> Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>

This must have a reasonable commit message added, and that commit
message must explain in detail what exactly is happening here.

But since I did read the patch I do not think that doing a looping
sleeping read is the way to fix this problem.

Instead, you should find some way to wait on the specific event that
needs to occur.