Re: [RESUBMIT Patch 1/1] net: replace if()/BUG with BUG_ON

[Alexander Drozdov <al.drozdov@gmail.com>]

On Wed, 17 Jun 2015 09:36:11 +0200, Frans Klaver wrote:
> On Wed, Jun 17, 2015 at 6:36 AM, Maninder Singh <maninder1.s@samsung.com> wrote:
>> Use BUG_ON(condition) instead of if(condition)/BUG() .
>>
>> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
>> Reviewed-by: Akhilesh Kumar <akhilesh.k@samsung.com>
>> ---
>>   net/packet/af_packet.c |    3 +--
>>   1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
>> index b5989c6..c91d405 100644
>> --- a/net/packet/af_packet.c
>> +++ b/net/packet/af_packet.c
>> @@ -547,8 +547,7 @@ static void prb_setup_retire_blk_timer(struct packet_sock *po, int tx_ring)
>>   {
>>          struct tpacket_kbdq_core *pkc;
>>
>> -       if (tx_ring)
>> -               BUG();
>> +       BUG_ON(tx_ring);
>>
>>          pkc = tx_ring ? GET_PBDQC_FROM_RB(&po->tx_ring) :
>>                          GET_PBDQC_FROM_RB(&po->rx_ring);
>
> I don't get this. We're not allowed to be using tx_ring, but we can
> and do handle it? Does that still warrant a BUG() or BUG_ON()? It's
> been in since the function introduction[0]. Can somebody explain?

TPACKET_V3 doesn't support tx for now, so the function is actualy never 
called with non-zero tx_ring. I think there were plans to add the
support. But retire timer for tx will not be needed anyway as it is
up to user to fill the ring buffer.

> Thanks,
> Frans
>
> [0] f6fb8f100b80 (af-packet: TPACKET_V3 flexible buffer implementation.)
>