linux-kernel - Re: [PATCH] bpftool: optimize if statement code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <dd4be9f4-71e3-4d71-bd71-1fda2c9572b6@linux.dev>
Date: Tue, 15 Oct 2024 11:16:42 -0700
From: Martin KaFai Lau <martin.lau@...ux.dev>
To: Liu Jing <liujing@...s.chinamobile.com>
Cc: Quentin Monnet <qmo@...nel.org>, ast@...nel.org, daniel@...earbox.net,
 andrii@...nel.org, eddyz87@...il.com, song@...nel.org,
 yonghong.song@...ux.dev, john.fastabend@...il.com, kpsingh@...nel.org,
 sdf@...ichev.me, haoluo@...gle.com, jolsa@...nel.org, bpf@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bpftool: optimize if statement code

On 10/15/24 5:11 AM, Quentin Monnet wrote:
> 2024-10-15 19:09 UTC+0800 ~ Liu Jing <liujing@...s.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@...s.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