Re: [PATCH net-next] fq_codel: remove set but not used variables 'prev_ecn_mark' and 'prev_drop_count'

[David Miller <davem@davemloft.net>]

From: YueHaibing <yuehaibing@huawei.com>
Date: Wed, 7 Aug 2019 21:10:55 +0800

> Fixes gcc '-Wunused-but-set-variable' warning:
> 
> net/sched/sch_fq_codel.c: In function fq_codel_dequeue:
> net/sched/sch_fq_codel.c:288:23: warning: variable prev_ecn_mark set but not used [-Wunused-but-set-variable]
> net/sched/sch_fq_codel.c:288:6: warning: variable prev_drop_count set but not used [-Wunused-but-set-variable]
> 
> They are not used since commit 77ddaff218fc ("fq_codel: Kill
> useless per-flow dropped statistic")
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Do you even compile test this stuff?

  CC [M]  net/sched/sch_fq_codel.o
net/sched/sch_fq_codel.c: In function ‘fq_codel_dequeue’:
net/sched/sch_fq_codel.c:309:42: error: ‘prev_drop_count’ undeclared (first use in this function); did you mean ‘page_ref_count’?
  flow->dropped += q->cstats.drop_count - prev_drop_count;
                                          ^~~~~~~~~~~~~~~
                                          page_ref_count
net/sched/sch_fq_codel.c:309:42: note: each undeclared identifier is reported only once for each function it appears in
net/sched/sch_fq_codel.c:310:40: error: ‘prev_ecn_mark’ undeclared (first use in this function); did you mean ‘pmd_pfn_mask’?
  flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
                                        ^~~~~~~~~~~~~
                                        pmd_pfn_mask
make[1]: *** [scripts/Makefile.build:274: net/sched/sch_fq_codel.o] Error 1
make: *** [Makefile:1769: net/sched/sch_fq_codel.o] Error 2