Subject: Re: [PATCH 01/11] bonding: Call dev_kfree_skby_any instead of kfree_skb.

From: [email-masked] (Eric W. Biederman)
Date: Mon, 10 Mar 2014 21:00:25 -0700

Eric Dumazet <[email-masked]> writes:

> On Mon, 2014-03-10 at 20:18 -0700, Eric W. Biederman wrote:
>> Replace kfree_skb with dev_kfree_skb_any in functions that can
>> be called in hard irq and other contexts.
>> 
>> Replace consume_skb with dev_consume_skb_any in functions that can
>> be called in hard irq and other contexts.
>> 
>> Signed-off-by: "Eric W. Biederman" <[email-masked]>
>> ---
>>  drivers/net/bonding/bond_3ad.c  |    2 +-
>>  drivers/net/bonding/bond_alb.c  |    2 +-
>>  drivers/net/bonding/bond_main.c |   14 +++++++-------
>>  3 files changed, 9 insertions(+), 9 deletions(-)
>> 
>> diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
>> index a2ef3f72de88..dee2a84a2929 100644
>> --- a/drivers/net/bonding/bond_3ad.c
>> +++ b/drivers/net/bonding/bond_3ad.c
>> @@ -2479,7 +2479,7 @@ out:
>>  	return NETDEV_TX_OK;
>>  err_free:
>>  	/* no suitable interface, frame not sent */
>> -	kfree_skb(skb);
>> +	dev_kfree_skb_any(skb);
>>  	goto out;
>>  }
>>  
>> diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>> index aaeeacf767f2..9cf836b67b15 100644
>> --- a/drivers/net/bonding/bond_alb.c
>> +++ b/drivers/net/bonding/bond_alb.c
>> @@ -1464,7 +1464,7 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
>>  	}
>>  
>>  	/* no suitable interface, frame not sent */
>> -	kfree_skb(skb);
>> +	dev_kfree_skb_any(skb);
>>  out:
>>  	return NETDEV_TX_OK;
>>  }
>> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>> index 730d72c706c9..63f8df8af4d4 100644
>> --- a/drivers/net/bonding/bond_main.c
>> +++ b/drivers/net/bonding/bond_main.c
>> @@ -1115,7 +1115,7 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
>>  	if (recv_probe) {
>>  		ret = recv_probe(skb, bond, slave);
>>  		if (ret == RX_HANDLER_CONSUMED) {
>> -			consume_skb(skb);
>> +			dev_consume_skb_any(skb);
>
> Why is this needed ? AFAIK we run in softirq here.

Except when we call printk in hard irq context.  Then we can easily have
a call trace like:

drivers/net/netconsole.c:write_msg
  netpoll_send_udp
    netpoll_send_skb_on_dev
      netpoll_poll_dev
        poll_napi
           poll_one_napi
         -------------------------
             tg3_poll
                tg3_poll_work   -- Or any other driver supporting netpoll
                   tg3_rx
         -------------------------
                     napi_gro_receive
                       napi_skb_finish
                         netif_receive_skb_internal
                           __netif_receive_skb
                             __netif_receive_skb_core
                                bond_handle_frame

>>  			return ret;
>>  		}
>>  	}
>> @@ -1132,7 +1132,7 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
>>  
>>  		if (unlikely(skb_cow_head(skb,
>>  					  skb->data - skb_mac_header(skb)))) {
>> -			kfree_skb(skb);
>> +			dev_kfree_skb_any(skb);
>
> same here.

Same reason as above.

>>  			return RX_HANDLER_CONSUMED;
>>  		}
>>  		ether_addr_copy(eth_hdr(skb)->h_dest, bond->dev->dev_addr);
>> @@ -3548,7 +3548,7 @@ static void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int sl
>>  		}

Eric