diff mbox series

bpftool: optimize if statement code

Message ID 20241015110944.6975-1-liujing@cmss.chinamobile.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpftool: optimize if statement code | expand

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Commit Message

liujing Oct. 15, 2024, 11:09 a.m. UTC 
Since both conditions are used to check whether len is valid, we can combine the two conditions into a single if statement
Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
---
 tools/bpf/bpftool/feature.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Quentin Monnet Oct. 15, 2024, 12:11 p.m. UTC | #1 
2024-10-15 19:09 UTC+0800 ~ Liu Jing <liujing@cmss.chinamobile.com>
> Since both conditions are used to check whether len is valid, we can combine the two conditions into a single if statement
> Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
> ---
>   tools/bpf/bpftool/feature.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
> index 4dbc4fcdf473..0121e0fd6949 100644
> --- a/tools/bpf/bpftool/feature.c
> +++ b/tools/bpf/bpftool/feature.c
> @@ -158,10 +158,9 @@ static int get_vendor_id(int ifindex)
>   
>   	len = read(fd, buf, sizeof(buf));
>   	close(fd);
> -	if (len < 0)
> -		return -1;
> -	if (len >= (ssize_t)sizeof(buf))
> +	if ((len < 0) || (len >= (ssize_t)sizeof(buf)))
>   		return -1;
> +
>   	buf[len] = '\0';
>   
>   	return strtol(buf, NULL, 0);


Thanks. I'm not strictly opposed to the change, but it doesn't bring 
much value in my opinion. I don't think this will "optimize" the 
statement beyond what the compiler does already.

Quentin
Martin KaFai Lau Oct. 15, 2024, 6:16 p.m. UTC | #2 
On 10/15/24 5:11 AM, Quentin Monnet wrote:
> 2024-10-15 19:09 UTC+0800 ~ Liu Jing <liujing@cmss.chinamobile.com>
>> Since both conditions are used to check whether len is valid, we can combine 
>> the two conditions into a single if statement
>> Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
>> ---
>>   tools/bpf/bpftool/feature.c | 5 ++---
>>   1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
>> index 4dbc4fcdf473..0121e0fd6949 100644
>> --- a/tools/bpf/bpftool/feature.c
>> +++ b/tools/bpf/bpftool/feature.c
>> @@ -158,10 +158,9 @@ static int get_vendor_id(int ifindex)
>>       len = read(fd, buf, sizeof(buf));
>>       close(fd);
>> -    if (len < 0)
>> -        return -1;
>> -    if (len >= (ssize_t)sizeof(buf))
>> +    if ((len < 0) || (len >= (ssize_t)sizeof(buf)))
>>           return -1;
>> +
>>       buf[len] = '\0';
>>       return strtol(buf, NULL, 0);
> 
> 
> Thanks. I'm not strictly opposed to the change, but it doesn't bring much value 
> in my opinion. I don't think this will "optimize" the statement beyond what the 
> compiler does already.

+1

The current code is good as is.

pw-bot: cr
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 4dbc4fcdf473..0121e0fd6949 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -158,10 +158,9 @@  static int get_vendor_id(int ifindex)
 
 	len = read(fd, buf, sizeof(buf));
 	close(fd);
-	if (len < 0)
-		return -1;
-	if (len >= (ssize_t)sizeof(buf))
+	if ((len < 0) || (len >= (ssize_t)sizeof(buf)))
 		return -1;
+
 	buf[len] = '\0';
 
 	return strtol(buf, NULL, 0);