* [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check
@ 2016-09-26 14:13 fgao
2016-09-26 15:17 ` Florian Westphal
0 siblings, 1 reply; 5+ messages in thread
From: fgao @ 2016-09-26 14:13 UTC (permalink / raw)
To: pablo, netfilter-devel; +Cc: gfree.wind, Gao Feng
From: Gao Feng <fgao@ikuai8.com>
Use not operation instead of condition check to simplify the codes.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
---
net/netfilter/xt_nfacct.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
index cf32759..7abb5b5 100644
--- a/net/netfilter/xt_nfacct.c
+++ b/net/netfilter/xt_nfacct.c
@@ -28,7 +28,7 @@ static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
overquota = nfnl_acct_overquota(par->net, skb, info->nfacct);
- return overquota == NFACCT_UNDERQUOTA ? false : true;
+ return !(overquota == NFACCT_UNDERQUOTA);
}
static int
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check
2016-09-26 14:13 [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check fgao
@ 2016-09-26 15:17 ` Florian Westphal
2016-09-27 0:36 ` Gao Feng
0 siblings, 1 reply; 5+ messages in thread
From: Florian Westphal @ 2016-09-26 15:17 UTC (permalink / raw)
To: fgao; +Cc: pablo, netfilter-devel, gfree.wind
fgao@ikuai8.com <fgao@ikuai8.com> wrote:
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
> index cf32759..7abb5b5 100644
> --- a/net/netfilter/xt_nfacct.c
> +++ b/net/netfilter/xt_nfacct.c
> @@ -28,7 +28,7 @@ static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
>
> overquota = nfnl_acct_overquota(par->net, skb, info->nfacct);
>
> - return overquota == NFACCT_UNDERQUOTA ? false : true;
> + return !(overquota == NFACCT_UNDERQUOTA);
I don't find one better than the other. If you need to change
it for some reason consider
"return overquota != NFACCT_UNDERQUOTA"
instead of this strange negation.
But really, I think its fine as-is.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check
2016-09-26 15:17 ` Florian Westphal
@ 2016-09-27 0:36 ` Gao Feng
2016-09-27 0:39 ` Florian Westphal
0 siblings, 1 reply; 5+ messages in thread
From: Gao Feng @ 2016-09-27 0:36 UTC (permalink / raw)
To: Florian Westphal; +Cc: Pablo Neira Ayuso, Netfilter Developer Mailing List
Hi Florian,
On Mon, Sep 26, 2016 at 11:17 PM, Florian Westphal <fw@strlen.de> wrote:
> fgao@ikuai8.com <fgao@ikuai8.com> wrote:
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
>> index cf32759..7abb5b5 100644
>> --- a/net/netfilter/xt_nfacct.c
>> +++ b/net/netfilter/xt_nfacct.c
>> @@ -28,7 +28,7 @@ static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
>>
>> overquota = nfnl_acct_overquota(par->net, skb, info->nfacct);
>>
>> - return overquota == NFACCT_UNDERQUOTA ? false : true;
>> + return !(overquota == NFACCT_UNDERQUOTA);
>
> I don't find one better than the other. If you need to change
> it for some reason consider
>
> "return overquota != NFACCT_UNDERQUOTA"
>
> instead of this strange negation.
Thanks, it is more simple use "!=".
>
> But really, I think its fine as-is.
It could decrease one condition check and jump.
Regards
Feng
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check
2016-09-27 0:36 ` Gao Feng
@ 2016-09-27 0:39 ` Florian Westphal
2016-09-27 1:04 ` Gao Feng
0 siblings, 1 reply; 5+ messages in thread
From: Florian Westphal @ 2016-09-27 0:39 UTC (permalink / raw)
To: Gao Feng
Cc: Florian Westphal, Pablo Neira Ayuso,
Netfilter Developer Mailing List
Gao Feng <fgao@ikuai8.com> wrote:
> >> diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
> >> index cf32759..7abb5b5 100644
> >> --- a/net/netfilter/xt_nfacct.c
> >> +++ b/net/netfilter/xt_nfacct.c
> >> @@ -28,7 +28,7 @@ static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
> >>
> >> overquota = nfnl_acct_overquota(par->net, skb, info->nfacct);
> >>
> >> - return overquota == NFACCT_UNDERQUOTA ? false : true;
> >> + return !(overquota == NFACCT_UNDERQUOTA);
> >
> > I don't find one better than the other. If you need to change
> > it for some reason consider
> >
> > "return overquota != NFACCT_UNDERQUOTA"
> >
> > instead of this strange negation.
>
> Thanks, it is more simple use "!=".
> >
> > But really, I think its fine as-is.
>
> It could decrease one condition check and jump.
gcc should emit same instructions for all these variants.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check
2016-09-27 0:39 ` Florian Westphal
@ 2016-09-27 1:04 ` Gao Feng
0 siblings, 0 replies; 5+ messages in thread
From: Gao Feng @ 2016-09-27 1:04 UTC (permalink / raw)
To: Florian Westphal; +Cc: Pablo Neira Ayuso, Netfilter Developer Mailing List
On Tue, Sep 27, 2016 at 8:39 AM, Florian Westphal <fw@strlen.de> wrote:
> Gao Feng <fgao@ikuai8.com> wrote:
>> >> diff --git a/net/netfilter/xt_nfacct.c b/net/netfilter/xt_nfacct.c
>> >> index cf32759..7abb5b5 100644
>> >> --- a/net/netfilter/xt_nfacct.c
>> >> +++ b/net/netfilter/xt_nfacct.c
>> >> @@ -28,7 +28,7 @@ static bool nfacct_mt(const struct sk_buff *skb, struct xt_action_param *par)
>> >>
>> >> overquota = nfnl_acct_overquota(par->net, skb, info->nfacct);
>> >>
>> >> - return overquota == NFACCT_UNDERQUOTA ? false : true;
>> >> + return !(overquota == NFACCT_UNDERQUOTA);
>> >
>> > I don't find one better than the other. If you need to change
>> > it for some reason consider
>> >
>> > "return overquota != NFACCT_UNDERQUOTA"
>> >
>> > instead of this strange negation.
>>
>> Thanks, it is more simple use "!=".
>> >
>> > But really, I think its fine as-is.
>>
>> It could decrease one condition check and jump.
>
> gcc should emit same instructions for all these variants.
Thanks Florian.
It is unnecessary to simplify it now.
Regards
Feng
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^ permalink raw reply [flat|nested] 5+ messages in thread
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2016-09-26 14:13 [PATCH nf-next] netfilter: xt_nfacct: Use not operation instead of condition check fgao
2016-09-26 15:17 ` Florian Westphal
2016-09-27 0:36 ` Gao Feng
2016-09-27 0:39 ` Florian Westphal
2016-09-27 1:04 ` Gao Feng
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