* [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c
@ 2017-01-11 1:32 fgao
2017-01-12 11:21 ` Pablo Neira Ayuso
0 siblings, 1 reply; 4+ messages in thread
From: fgao @ 2017-01-11 1:32 UTC (permalink / raw)
To: pablo, netfilter-devel; +Cc: gfree.wind, Gao Feng
From: Gao Feng <fgao@ikuai8.com>
The return value of nf_tables_table_lookup is valid pointer or one
pointer error. There are two cases totally.
case1: IS_ERR(table) is true, it would return the error or reset the
table as NULL, it is unnecessary to perform the latter check
"table != NULL".
case2: IS_ERR(obj) is false, the table is one valid pointer. It is also
unnecessary to perform that check.
The nf_tables_newset and nf_tables_newobj have same logic codes.
In summary, we could move the block of condition check "table != NULL"
in the else block to eliminate the original condition checks.
Signed-off-by: Gao Feng <fgao@ikuai8.com>
---
net/netfilter/nf_tables_api.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index a019a87..3d7267f 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
if (PTR_ERR(table) != -ENOENT)
return PTR_ERR(table);
table = NULL;
- }
-
- if (table != NULL) {
+ } else {
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
if (nlh->nlmsg_flags & NLM_F_REPLACE)
@@ -2964,9 +2962,7 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk,
if (PTR_ERR(set) != -ENOENT)
return PTR_ERR(set);
set = NULL;
- }
-
- if (set != NULL) {
+ } else {
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
if (nlh->nlmsg_flags & NLM_F_REPLACE)
@@ -4154,9 +4150,7 @@ static int nf_tables_newobj(struct net *net, struct sock *nlsk,
return err;
obj = NULL;
- }
-
- if (obj != NULL) {
+ } else {
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c
2017-01-11 1:32 [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c fgao
@ 2017-01-12 11:21 ` Pablo Neira Ayuso
2017-01-12 15:10 ` Gao Feng
0 siblings, 1 reply; 4+ messages in thread
From: Pablo Neira Ayuso @ 2017-01-12 11:21 UTC (permalink / raw)
To: fgao; +Cc: netfilter-devel, gfree.wind
On Wed, Jan 11, 2017 at 09:32:15AM +0800, fgao@ikuai8.com wrote:
> From: Gao Feng <fgao@ikuai8.com>
>
> The return value of nf_tables_table_lookup is valid pointer or one
> pointer error. There are two cases totally.
> case1: IS_ERR(table) is true, it would return the error or reset the
> table as NULL, it is unnecessary to perform the latter check
> "table != NULL".
> case2: IS_ERR(obj) is false, the table is one valid pointer. It is also
> unnecessary to perform that check.
> The nf_tables_newset and nf_tables_newobj have same logic codes.
>
> In summary, we could move the block of condition check "table != NULL"
> in the else block to eliminate the original condition checks.
>
> Signed-off-by: Gao Feng <fgao@ikuai8.com>
> ---
> net/netfilter/nf_tables_api.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index a019a87..3d7267f 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
> if (PTR_ERR(table) != -ENOENT)
> return PTR_ERR(table);
> table = NULL;
We follow up with table = NULL down the code, I think this breaks.
> - }
> -
> - if (table != NULL) {
> + } else {
> if (nlh->nlmsg_flags & NLM_F_EXCL)
> return -EEXIST;
> if (nlh->nlmsg_flags & NLM_F_REPLACE)
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c
2017-01-12 11:21 ` Pablo Neira Ayuso
@ 2017-01-12 15:10 ` Gao Feng
2017-01-16 13:38 ` Pablo Neira Ayuso
0 siblings, 1 reply; 4+ messages in thread
From: Gao Feng @ 2017-01-12 15:10 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: Netfilter Developer Mailing List
Hi Pablo,
On Thu, Jan 12, 2017 at 7:21 PM, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Wed, Jan 11, 2017 at 09:32:15AM +0800, fgao@ikuai8.com wrote:
>> From: Gao Feng <fgao@ikuai8.com>
>>
>> The return value of nf_tables_table_lookup is valid pointer or one
>> pointer error. There are two cases totally.
>> case1: IS_ERR(table) is true, it would return the error or reset the
>> table as NULL, it is unnecessary to perform the latter check
>> "table != NULL".
>> case2: IS_ERR(obj) is false, the table is one valid pointer. It is also
>> unnecessary to perform that check.
>> The nf_tables_newset and nf_tables_newobj have same logic codes.
>>
>> In summary, we could move the block of condition check "table != NULL"
>> in the else block to eliminate the original condition checks.
>>
>> Signed-off-by: Gao Feng <fgao@ikuai8.com>
>> ---
>> net/netfilter/nf_tables_api.c | 12 +++---------
>> 1 file changed, 3 insertions(+), 9 deletions(-)
>>
>> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
>> index a019a87..3d7267f 100644
>> --- a/net/netfilter/nf_tables_api.c
>> +++ b/net/netfilter/nf_tables_api.c
>> @@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
>> if (PTR_ERR(table) != -ENOENT)
>> return PTR_ERR(table);
>> table = NULL;
>
> We follow up with table = NULL down the code, I think this breaks.
Look at the following nf_tables_table_lookup codes, it won't return NULL.
It returns one valid table pointer or one error.
static struct nft_table *nf_tables_table_lookup(const struct nft_af_info *afi,
const struct nlattr *nla,
u8 genmask)
{
struct nft_table *table;
if (nla == NULL)
return ERR_PTR(-EINVAL);
table = nft_table_lookup(afi, nla, genmask);
if (table != NULL)
return table;
return ERR_PTR(-ENOENT);
}
When returns one error, IS_ERR(table) is true, it then returns error
or reset table as NULL.
Wehn returns a valid table pointer, IS_ERR(table) is false, we could
perform the latter codes like "if (nlh->nlmsg_flags & NLM_F_EXCL)"
directly.
Regards
Feng
>
>> - }
>> -
>> - if (table != NULL) {
>> + } else {
>> if (nlh->nlmsg_flags & NLM_F_EXCL)
>> return -EEXIST;
>> if (nlh->nlmsg_flags & NLM_F_REPLACE)
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c
2017-01-12 15:10 ` Gao Feng
@ 2017-01-16 13:38 ` Pablo Neira Ayuso
0 siblings, 0 replies; 4+ messages in thread
From: Pablo Neira Ayuso @ 2017-01-16 13:38 UTC (permalink / raw)
To: Gao Feng; +Cc: Netfilter Developer Mailing List
On Thu, Jan 12, 2017 at 11:10:11PM +0800, Gao Feng wrote:
> Hi Pablo,
>
> On Thu, Jan 12, 2017 at 7:21 PM, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > On Wed, Jan 11, 2017 at 09:32:15AM +0800, fgao@ikuai8.com wrote:
> >> From: Gao Feng <fgao@ikuai8.com>
> >>
> >> The return value of nf_tables_table_lookup is valid pointer or one
> >> pointer error. There are two cases totally.
> >> case1: IS_ERR(table) is true, it would return the error or reset the
> >> table as NULL, it is unnecessary to perform the latter check
> >> "table != NULL".
> >> case2: IS_ERR(obj) is false, the table is one valid pointer. It is also
> >> unnecessary to perform that check.
> >> The nf_tables_newset and nf_tables_newobj have same logic codes.
> >>
> >> In summary, we could move the block of condition check "table != NULL"
> >> in the else block to eliminate the original condition checks.
> >>
> >> Signed-off-by: Gao Feng <fgao@ikuai8.com>
> >> ---
> >> net/netfilter/nf_tables_api.c | 12 +++---------
> >> 1 file changed, 3 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> >> index a019a87..3d7267f 100644
> >> --- a/net/netfilter/nf_tables_api.c
> >> +++ b/net/netfilter/nf_tables_api.c
> >> @@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
> >> if (PTR_ERR(table) != -ENOENT)
> >> return PTR_ERR(table);
> >> table = NULL;
> >
> > We follow up with table = NULL down the code, I think this breaks.
>
> Look at the following nf_tables_table_lookup codes, it won't return NULL.
> It returns one valid table pointer or one error.
>
> static struct nft_table *nf_tables_table_lookup(const struct nft_af_info *afi,
> const struct nlattr *nla,
> u8 genmask)
> {
> struct nft_table *table;
>
> if (nla == NULL)
> return ERR_PTR(-EINVAL);
>
> table = nft_table_lookup(afi, nla, genmask);
> if (table != NULL)
> return table;
>
> return ERR_PTR(-ENOENT);
> }
>
> When returns one error, IS_ERR(table) is true, it then returns error
> or reset table as NULL.
> Wehn returns a valid table pointer, IS_ERR(table) is false, we could
> perform the latter codes like "if (nlh->nlmsg_flags & NLM_F_EXCL)"
> directly.
Right.
Then, I think we can remove the unneccessary table = NULL assigment:
@@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
if (PTR_ERR(table) != -ENOENT)
return PTR_ERR(table);
table = NULL; <----- this
- }
-
- if (table != NULL) {
+ } else {
if (nlh->nlmsg_flags & NLM_F_EXCL)
return -EEXIST;
if (nlh->nlmsg_flags & NLM_F_REPLACE)
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-01-16 13:38 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-01-11 1:32 [PATCH nf-next 1/1] netfilter: nf_tables: Refine the codes to eliminate useless condition checks in nf_tables_api.c fgao
2017-01-12 11:21 ` Pablo Neira Ayuso
2017-01-12 15:10 ` Gao Feng
2017-01-16 13:38 ` Pablo Neira Ayuso
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