Re: [PATCH v3 2/5] staging: et131x: drop packet when error occurs in et131x_tx

Denis Kirjanov
2013-11-22T09:17:24Z

On 11/22/13, Mark Einon <mark.einon@gmail.com> wrote:
> On Wed, Nov 20, 2013 at 03:55:27PM +0800, ZHAO Gang wrote:
>> As TODO file suggested, drop packet instead of return NETDEV_TX_BUSY
>> when tx failed.
>>
>> et131x_tx calls function et131x_send_packets, I put the work of
>> et131x_send_packets directly into et131x_tx, and made some changes to
>> let the code more readable.
>>
>> Signed-off-by: ZHAO Gang <gamerh2o@gmail.com>
>
> Acked-by: Mark Einon <mark.einon@gmail.com>
>
>> ---
>> drivers/staging/et131x/et131x.c | 84
>> +++++++++++------------------------------
>> 1 file changed, 22 insertions(+), 62 deletions(-)
>>
>> diff --git a/drivers/staging/et131x/et131x.c
>> b/drivers/staging/et131x/et131x.c
>> index 836a4db..cda037a 100644
>> --- a/drivers/staging/et131x/et131x.c
>> +++ b/drivers/staging/et131x/et131x.c
>> @@ -3123,55 +3123,6 @@ static int send_packet(struct sk_buff *skb, struct
>> et131x_adapter *adapter)
>> return 0;
>> }
>>
>> -/* et131x_send_packets - This function is called by the OS to send
>> packets
>> - * @skb: the packet(s) to send
>> - * @netdev:device on which to TX the above packet(s)
>> - *
>> - * Return 0 in almost all cases; non-zero value in extreme hard failure
>> only
>> - */
>> -static int et131x_send_packets(struct sk_buff *skb, struct net_device
>> *netdev)
>> -{
>> - int status = 0;
>> - struct et131x_adapter *adapter = netdev_priv(netdev);
>> -
>> - /* Send these packets
>> - *
>> - * NOTE: The Linux Tx entry point is only given one packet at a time
>> - * to Tx, so the PacketCount and it's array used makes no sense here
>> - */
>> -
>> - /* TCB is not available */
>> - if (adapter->tx_ring.used >= NUM_TCB) {
>> - /* NOTE: If there's an error on send, no need to queue the
>> - * packet under Linux; if we just send an error up to the
>> - * netif layer, it will resend the skb to us.
>> - */
>> - status = -ENOMEM;
>> - } else {
>> - /* We need to see if the link is up; if it's not, make the
>> - * netif layer think we're good and drop the packet
>> - */
>> - if ((adapter->flags & FMP_ADAPTER_FAIL_SEND_MASK) ||
>> - !netif_carrier_ok(netdev)) {
>> - dev_kfree_skb_any(skb);
>> - skb = NULL;
>> -
>> - adapter->net_stats.tx_dropped++;
>> - } else {
>> - status = send_packet(skb, adapter);
>> - if (status != 0 && status != -ENOMEM) {
>> - /* On any other error, make netif think we're
>> - * OK and drop the packet
>> - */
>> - dev_kfree_skb_any(skb);
>> - skb = NULL;
>> - adapter->net_stats.tx_dropped++;
>> - }
>> - }
>> - }
>> - return status;
>> -}
>> -
>> /* free_send_packet - Recycle a struct tcb
>> * @adapter: pointer to our adapter
>> * @tcb: pointer to struct tcb
>> @@ -4537,12 +4488,9 @@ static void et131x_multicast(struct net_device
>> *netdev)
>> /* et131x_tx - The handler to tx a packet on the device
>> * @skb: data to be Tx'd
>> * @netdev: device on which data is to be Tx'd
>> - *
>> - * Returns 0 on success, errno on failure (as defined in errno.h)
>> */
>> -static int et131x_tx(struct sk_buff *skb, struct net_device *netdev)
>> +static netdev_tx_t et131x_tx(struct sk_buff *skb, struct net_device
>> *netdev)
>> {
>> - int status = 0;
>> struct et131x_adapter *adapter = netdev_priv(netdev);
>>
>> /* stop the queue if it's getting full */
>> @@ -4553,17 +4501,29 @@ static int et131x_tx(struct sk_buff *skb, struct
>> net_device *netdev)
>> /* Save the timestamp for the TX timeout watchdog */
>> netdev->trans_start = jiffies;
>>
>> - /* Call the device-specific data Tx routine */
>> - status = et131x_send_packets(skb, netdev);
>> + /* TCB is not available */
>> + if (adapter->tx_ring.used >= NUM_TCB)
>> + goto drop;

That's wrong. You have to properly manage tx queue and not just drop packets

>> - /* Check status and manage the netif queue if necessary */
>> - if (status != 0) {
>> - if (status == -ENOMEM)
>> - status = NETDEV_TX_BUSY;
>> - else
>> - status = NETDEV_TX_OK;
>> + /* We need to see if the link is up; if it's not, make the
>> + * netif layer think we're good and drop the packet
>> + */
>> + if ((adapter->flags & FMP_ADAPTER_FAIL_SEND_MASK) ||
>> + !netif_carrier_ok(netdev)) {
>> + goto drop;
>> + } else {
>> + if (!send_packet(skb, adapter))
>> + goto out;
>> + /* On error (send_packet returns != 0), make netif
>> + * think we're OK and drop the packet
>> + */
>> }
>> - return status;
>> +
>> +drop:
>> + dev_kfree_skb_any(skb);
>> + adapter->net_stats.tx_dropped++;
>> +out:
>> + return NETDEV_TX_OK;
>> }
>>
>> /* et131x_tx_timeout - Timeout handler
>> --
>> 1.8.3.1
>>
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--
Regards,
Denis