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

From: Alexander Drozdov
Date: Wed Jun 17 2015 - 04:26:39 EST


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@xxxxxxxxxxx> wrote:
Use BUG_ON(condition) instead of if(condition)/BUG() .

Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>
Reviewed-by: Akhilesh Kumar <akhilesh.k@xxxxxxxxxxx>
---
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.)

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