diff mbox series

[v1] RDMA/sa_query: use validate not parser in ib_nl_is_good_resolve_resp

Message ID 20231230051956.82499-1-linma@zju.edu.cn
State New
Headers
Series [v1] RDMA/sa_query: use validate not parser in ib_nl_is_good_resolve_resp |

Commit Message

Lin Ma Dec. 30, 2023, 5:19 a.m. UTC 
  The attributes array `tb` in ib_nl_is_good_resolve_resp is never used
after the parsing. Therefore use nla_validate_deprecated function here
for improvement.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
 drivers/infiniband/core/sa_query.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Leon Romanovsky Dec. 30, 2023, 3:44 p.m. UTC | #1 
On Sat, Dec 30, 2023 at 01:19:56PM +0800, Lin Ma wrote:
> The attributes array `tb` in ib_nl_is_good_resolve_resp is never used
> after the parsing. Therefore use nla_validate_deprecated function here
> for improvement.

What did this change improve?

> 
> Signed-off-by: Lin Ma <linma@zju.edu.cn>
> ---
>  drivers/infiniband/core/sa_query.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
> index 8175dde60b0a..c7407a53fcda 100644
> --- a/drivers/infiniband/core/sa_query.c
> +++ b/drivers/infiniband/core/sa_query.c
> @@ -1047,14 +1047,13 @@ int ib_nl_handle_set_timeout(struct sk_buff *skb,
>  
>  static inline int ib_nl_is_good_resolve_resp(const struct nlmsghdr *nlh)
>  {
> -	struct nlattr *tb[LS_NLA_TYPE_MAX];
>  	int ret;
>  
>  	if (nlh->nlmsg_flags & RDMA_NL_LS_F_ERR)
>  		return 0;
>  
> -	ret = nla_parse_deprecated(tb, LS_NLA_TYPE_MAX - 1, nlmsg_data(nlh),
> -				   nlmsg_len(nlh), ib_nl_policy, NULL);
> +	ret = nla_validate_deprecated(nlmsg_data(nlh), nlmsg_len(nlh),
> +				      LS_NLA_TYPE_MAX - 1, ib_nl_policy, NULL);
>  	if (ret)
>  		return 0;
>  
> -- 
> 2.17.1
>
Lin Ma Dec. 31, 2023, 5:27 a.m. UTC | #2 
Hello Leon,

> > The attributes array `tb` in ib_nl_is_good_resolve_resp is never used
> > after the parsing. Therefore use nla_validate_deprecated function here
> > for improvement.
> 
> What did this change improve?
> 

To my concern, the nla_validate_deprecated, compared to nla_parse_deprecated,
will at lease save a memset in function nla_parse_deprecated

```
if (tb)
    memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
```

Morever, because the `nla_validate_deprecated` just validate the attributes
array and will not try to retrieve the nla pointers. It shall be faster
and cleaner here :D.

Regards
Lin
Leon Romanovsky Dec. 31, 2023, 3:49 p.m. UTC | #3 
On Sun, Dec 31, 2023 at 01:27:59PM +0800, Lin Ma wrote:
> Hello Leon,
> 
> > > The attributes array `tb` in ib_nl_is_good_resolve_resp is never used
> > > after the parsing. Therefore use nla_validate_deprecated function here
> > > for improvement.
> > 
> > What did this change improve?
> > 
> 
> To my concern, the nla_validate_deprecated, compared to nla_parse_deprecated,
> will at lease save a memset in function nla_parse_deprecated
> 
> ```
> if (tb)
>     memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
> ```
> 
> Morever, because the `nla_validate_deprecated` just validate the attributes
> array and will not try to retrieve the nla pointers. It shall be faster
> and cleaner here :D.

We don't care about speed in this path.
Let's leave the code as is.

Thanks

> 
> Regards
> Lin
diff mbox series

Patch

diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
index 8175dde60b0a..c7407a53fcda 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -1047,14 +1047,13 @@  int ib_nl_handle_set_timeout(struct sk_buff *skb,
 
 static inline int ib_nl_is_good_resolve_resp(const struct nlmsghdr *nlh)
 {
-	struct nlattr *tb[LS_NLA_TYPE_MAX];
 	int ret;
 
 	if (nlh->nlmsg_flags & RDMA_NL_LS_F_ERR)
 		return 0;
 
-	ret = nla_parse_deprecated(tb, LS_NLA_TYPE_MAX - 1, nlmsg_data(nlh),
-				   nlmsg_len(nlh), ib_nl_policy, NULL);
+	ret = nla_validate_deprecated(nlmsg_data(nlh), nlmsg_len(nlh),
+				      LS_NLA_TYPE_MAX - 1, ib_nl_policy, NULL);
 	if (ret)
 		return 0;