Re: [PATCH net-next v2 1/2] net: sched: pie: refactor code

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 31 Dec 2019 16:53:15 +0530
gautamramk@gmail.com wrote:

> From: "Mohit P. Tahiliani" <tahiliani@nitk.edu.in>
> 
> This patch is a precursor for the addition of the Flow Queue Proportional
> Integral Controller Enhanced (FQ-PIE) qdisc. The patch removes functions
> and structures common to both PIE and FQ-PIE and moves it to the
> header file pie.h
> 
> Signed-off-by: Mohit P. Tahiliani <tahiliani@nitk.edu.in>
> Signed-off-by: Sachin D. Patil <sdp.sachin@gmail.com>
> Signed-off-by: V. Saicharan <vsaicharan1998@gmail.com>
> Signed-off-by: Mohit Bhasi <mohitbhasi1998@gmail.com>
> Signed-off-by: Leslie Monis <lesliemonis@gmail.com>
> Signed-off-by: Gautam Ramakrishnan <gautamramk@gmail.com>
> ---
>  include/net/pie.h   | 400 ++++++++++++++++++++++++++++++++++++++++++++
>  net/sched/sch_pie.c | 386 ++----------------------------------------
>  2 files changed, 415 insertions(+), 371 deletions(-)
>  create mode 100644 include/net/pie.h
> 
> diff --git a/include/net/pie.h b/include/net/pie.h


Adding lots of static functions in a header file is not the way
to get code reuse in Linux kernel. It looks like you just did
large copy/paste from existing sch_pie.c to new header file.

You can use reuse data structures and small 'static inline' functions in a header file.
But putting code like drop_early in a header file is not best
practice.

You need to create a real kernel API for this kind of thing
by making a helper module which is reused by multiple places.