Discussion:
[PATCH net v1 1/2] amd-xgbe: Properly handle feature changes via ethtool
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Tom Lendacky
2014-10-22 16:26:11 UTC
Permalink
The ndo_set_features callback function was improperly using an unsigned
int to save the current feature value for features such as NETIF_F_RXCSUM.
Since that feature is in the upper 32 bits of a 64 bit variable the
result was always 0 making it not possible to actually turn off the
hardware RX checksum support. Change the unsigned int type to the
netdev_features_t type in order to properly capture the current value
and perform the proper operation.

Signed-off-by: Tom Lendacky <***@amd.com>
---
drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 2955499..a480b23 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -1465,7 +1465,7 @@ static int xgbe_set_features(struct net_device *netdev,
{
struct xgbe_prv_data *pdata = netdev_priv(netdev);
struct xgbe_hw_if *hw_if = &pdata->hw_if;
- unsigned int rxcsum, rxvlan, rxvlan_filter;
+ netdev_features_t rxcsum, rxvlan, rxvlan_filter;

rxcsum = pdata->netdev_features & NETIF_F_RXCSUM;
rxvlan = pdata->netdev_features & NETIF_F_HW_VLAN_CTAG_RX;
Tom Lendacky
2014-10-22 16:26:17 UTC
Permalink
Currently the amd-xgbe driver increments the packets processed counter
each time a descriptor is processed. Since a packet can be represented
by more than one descriptor incrementing the counter in this way is not
appropriate. Also, since multiple descriptors cause the budget check
to be short circuited, sometimes the returned value from the poll
function would be larger than the budget value resulting in a WARN_ONCE
being triggered.

Update the polling logic to properly account for the number of packets
processed and exit when the budget value is reached.

Signed-off-by: Tom Lendacky <***@amd.com>
---
drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index a480b23..2349ea9 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -1598,7 +1598,8 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)
struct skb_shared_hwtstamps *hwtstamps;
unsigned int incomplete, error, context_next, context;
unsigned int len, put_len, max_len;
- int received = 0;
+ unsigned int received = 0;
+ int packet_count = 0;

DBGPR("-->xgbe_rx_poll: budget=%d\n", budget);

@@ -1608,7 +1609,7 @@ static int xgbe_rx_poll(struct xgbe_channel *channel, int budget)

rdata = XGBE_GET_DESC_DATA(ring, ring->cur);
packet = &ring->packet_data;
- while (received < budget) {
+ while (packet_count < budget) {
DBGPR(" cur = %d\n", ring->cur);

/* First time in loop see if we need to restore state */
@@ -1662,7 +1663,7 @@ read_again:
if (packet->errors)
DBGPR("Error in received packet\n");
dev_kfree_skb(skb);
- continue;
+ goto next_packet;
}

if (!context) {
@@ -1677,7 +1678,7 @@ read_again:
}

dev_kfree_skb(skb);
- continue;
+ goto next_packet;
}
memcpy(skb_tail_pointer(skb), rdata->skb->data,
put_len);
@@ -1694,7 +1695,7 @@ read_again:

/* Stray Context Descriptor? */
if (!skb)
- continue;
+ goto next_packet;

/* Be sure we don't exceed the configured MTU */
max_len = netdev->mtu + ETH_HLEN;
@@ -1705,7 +1706,7 @@ read_again:
if (skb->len > max_len) {
DBGPR("packet length exceeds configured MTU\n");
dev_kfree_skb(skb);
- continue;
+ goto next_packet;
}

#ifdef XGMAC_ENABLE_RX_PKT_DUMP
@@ -1739,6 +1740,9 @@ read_again:

netdev->last_rx = jiffies;
napi_gro_receive(&pdata->napi, skb);
+
+next_packet:
+ packet_count++;
}

/* Check if we need to save state before leaving */
@@ -1752,9 +1756,9 @@ read_again:
rdata->state.error = error;
}

- DBGPR("<--xgbe_rx_poll: received = %d\n", received);
+ DBGPR("<--xgbe_rx_poll: packet_count = %d\n", packet_count);

- return received;
+ return packet_count;
}

static int xgbe_poll(struct napi_struct *napi, int budget)
David Miller
2014-10-22 21:51:01 UTC
Permalink
From: Tom Lendacky <***@amd.com>
Date: Wed, 22 Oct 2014 11:26:05 -0500
The following series of patches includes fixes to the driver.
- Properly handle feature changes via ethtool by using correctly sized
variables
- Perform proper napi packet counting and budget checking
This patch series is based on net.
Series applied, thanks Tom.

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