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

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

[Maninder Singh]

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);
-- 
1.7.1

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

[Michael S. Tsirkin]

On Wed, Jun 17, 2015 at 10:06:01AM +0530, Maninder Singh 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>

Why not?

Acked-by: Michael S. Tsirkin <mst@redhat.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);
> -- 
> 1.7.1

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

[Frans Klaver]

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?

Thanks,
Frans

[0] f6fb8f100b80 (af-packet: TPACKET_V3 flexible buffer implementation.)

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

[Alexander Drozdov]

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.)
>

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

[Frans Klaver]

On Wed, Jun 17, 2015 at 10:26 AM, Alexander Drozdov
<al.drozdov@gmail.com> wrote:
> 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.

Ah, that explains something. If retire timer is not going to be needed
for tx, wouldn't it be better to remove the whole tx_ring handling
from this function altogether, rather than changing the BUG()?

Thanks,
Frans

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

[David Miller]

From: Frans Klaver <fransklaver@gmail.com>
Date: Wed, 17 Jun 2015 10:30:18 +0200

> Ah, that explains something. If retire timer is not going to be needed
> for tx, wouldn't it be better to remove the whole tx_ring handling
> from this function altogether, rather than changing the BUG()?

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

[David Miller]

From: Frans Klaver <fransklaver@gmail.com>
Date: Wed, 17 Jun 2015 10:30:18 +0200

> Ah, that explains something. If retire timer is not going to be needed
> for tx, wouldn't it be better to remove the whole tx_ring handling
> from this function altogether, rather than changing the BUG()?

Agreed.