Re: [PATCH bpf-next v1] bpf: fix bpf_skb_pull_data documentation

[Quentin Monnet <quentin@isovalent.com>]

On 15/07/2022 14:43, Daniel Borkmann wrote:
> On 7/15/22 12:47 AM, Joanne Koong wrote:
>> Fix documentation for bpf_skb_pull_data() helper for
>> when flags == 0.
>>
>> Fixes: fa15601ab31e ("bpf: add documentation for eBPF helpers (33-41)")
>> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
>> ---
>>   include/uapi/linux/bpf.h       | 3 ++-
>>   tools/include/uapi/linux/bpf.h | 3 ++-
>>   2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>> index 379e68fb866f..a80c1f6bbe25 100644
>> --- a/include/uapi/linux/bpf.h
>> +++ b/include/uapi/linux/bpf.h
>> @@ -2361,7 +2361,8 @@ union bpf_attr {
>>    *         Pull in non-linear data in case the *skb* is non-linear
>> and not
>>    *         all of *len* are part of the linear section. Make *len*
>> bytes
>>    *         from *skb* readable and writable. If a zero value is
>> passed for
>> - *         *len*, then the whole length of the *skb* is pulled.
>> + *        *len*, then all bytes in the head of the skb will be made
>> readable
> 
> Quentin, should the formatting be '*skb*' instead of 'skb'?

Correct

> Maybe it's more clear if we speak of 'all bytes in the linear part'
> instead of 'all
> bytes in the head' of the skb to make it clearer? Either is ok with me
> though.

Good suggestion, “linear part” is maybe easier to understand given that
the paragraph has no other mention the “head”.

Would it be worth, even, linking to e.g. Dave's doc
(http://vger.kernel.org/~davem/skb.html) here, to provide more details?
People reading the header file may not need that, but folks reading the
generated man page may not be aware of what a skb contains.

Quentin