Re: [PATCH] bpf: hide a possibly unused variable

[Daniel Borkmann]

On 02/20/2018 11:08 PM, Arnd Bergmann wrote:
> On Tue, Feb 20, 2018 at 10:44 PM, Daniel Borkmann  
> wrote:
>> Hi Arnd,
>>
>> On 02/20/2018 10:16 PM, Arnd Bergmann wrote:
>>> The only user of this variable is inside of an #ifdef, causing
>>> a warning without CONFIG_INET:
>>>
>>> net/core/filter.c: In function 'bpf_sock_ops_cb_flags_set':
>>> net/core/filter.c:3382:6: error: unused variable 'val' 
>>> [-Werror=unused-variable]
>>>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
>>>
>>> This adds the same #ifdef around the declaration.
>>>
>>> Fixes: b13d88072172 ("bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock")
>>> Signed-off-by: Arnd Bergmann 
>>> ---
>>>  net/core/filter.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/net/core/filter.c b/net/core/filter.c
>>> index 08ab4c65a998..c3dc6d60b4bb 100644
>>> --- a/net/core/filter.c
>>> +++ b/net/core/filter.c
>>> @@ -3379,7 +3379,9 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct 
>>> bpf_sock_ops_kern *, bpf_sock,
>>>  int, argval)
>>>  {
>>>   struct sock *sk = bpf_sock->sk;
>>> +#ifdef CONFIG_INET
>>>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
>>> +#endif
>>
>> Looks good, thanks for the fix!
>>
>> Could you move the existing '#ifdef CONFIG_INET' to the beginning of
>> the function given the only error in case of !CONFIG_INET is -EINVAL
>> anyway? That would at least not increase the ifdef ugliness further.
> 
> Sure, sent a new version now. I decided to clean up that #ifdef
> check as well, since a IS_ENABLED() check is nicer anway.

Looks great, thanks! I'll get it into bpf once the pending pr got pulled.

Re: [PATCH] bpf: hide a possibly unused variable

[Arnd Bergmann]

On Tue, Feb 20, 2018 at 10:44 PM, Daniel Borkmann  wrote:
> Hi Arnd,
>
> On 02/20/2018 10:16 PM, Arnd Bergmann wrote:
>> The only user of this variable is inside of an #ifdef, causing
>> a warning without CONFIG_INET:
>>
>> net/core/filter.c: In function 'bpf_sock_ops_cb_flags_set':
>> net/core/filter.c:3382:6: error: unused variable 'val' 
>> [-Werror=unused-variable]
>>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
>>
>> This adds the same #ifdef around the declaration.
>>
>> Fixes: b13d88072172 ("bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock")
>> Signed-off-by: Arnd Bergmann 
>> ---
>>  net/core/filter.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/net/core/filter.c b/net/core/filter.c
>> index 08ab4c65a998..c3dc6d60b4bb 100644
>> --- a/net/core/filter.c
>> +++ b/net/core/filter.c
>> @@ -3379,7 +3379,9 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct 
>> bpf_sock_ops_kern *, bpf_sock,
>>  int, argval)
>>  {
>>   struct sock *sk = bpf_sock->sk;
>> +#ifdef CONFIG_INET
>>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
>> +#endif
>
> Looks good, thanks for the fix!
>
> Could you move the existing '#ifdef CONFIG_INET' to the beginning of
> the function given the only error in case of !CONFIG_INET is -EINVAL
> anyway? That would at least not increase the ifdef ugliness further.

Sure, sent a new version now. I decided to clean up that #ifdef
check as well, since a IS_ENABLED() check is nicer anway.

   Arnd

Re: [PATCH] bpf: hide a possibly unused variable

[Daniel Borkmann]

Hi Arnd,

On 02/20/2018 10:16 PM, Arnd Bergmann wrote:
> The only user of this variable is inside of an #ifdef, causing
> a warning without CONFIG_INET:
> 
> net/core/filter.c: In function 'bpf_sock_ops_cb_flags_set':
> net/core/filter.c:3382:6: error: unused variable 'val' 
> [-Werror=unused-variable]
>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
> 
> This adds the same #ifdef around the declaration.
> 
> Fixes: b13d88072172 ("bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock")
> Signed-off-by: Arnd Bergmann 
> ---
>  net/core/filter.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 08ab4c65a998..c3dc6d60b4bb 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -3379,7 +3379,9 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct 
> bpf_sock_ops_kern *, bpf_sock,
>  int, argval)
>  {
>   struct sock *sk = bpf_sock->sk;
> +#ifdef CONFIG_INET
>   int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
> +#endif

Looks good, thanks for the fix!

Could you move the existing '#ifdef CONFIG_INET' to the beginning of
the function given the only error in case of !CONFIG_INET is -EINVAL
anyway? That would at least not increase the ifdef ugliness further.

Thanks a lot,
Daniel

>   if (!sk_fullsock(sk))
>   return -EINVAL;
> 

[PATCH] bpf: hide a possibly unused variable

[Arnd Bergmann]

The only user of this variable is inside of an #ifdef, causing
a warning without CONFIG_INET:

net/core/filter.c: In function 'bpf_sock_ops_cb_flags_set':
net/core/filter.c:3382:6: error: unused variable 'val' [-Werror=unused-variable]
  int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;

This adds the same #ifdef around the declaration.

Fixes: b13d88072172 ("bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock")
Signed-off-by: Arnd Bergmann 
---
 net/core/filter.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 08ab4c65a998..c3dc6d60b4bb 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3379,7 +3379,9 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct 
bpf_sock_ops_kern *, bpf_sock,
   int, argval)
 {
struct sock *sk = bpf_sock->sk;
+#ifdef CONFIG_INET
int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS;
+#endif
 
if (!sk_fullsock(sk))
return -EINVAL;
-- 
2.9.0