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SubjectRe: [PATCH BUGFIX] block, bfq: update wr_busy_queues if needed on a queue split
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> Il giorno 19 giu 2017, alle ore 09:38, kbuild test robot <lkp@intel.com> ha scritto:
>
> Hi Paolo,
>
> [auto build test WARNING on v4.12-rc5]
> [also build test WARNING on next-20170616]
> [cannot apply to block/for-next]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Paolo-Valente/block-bfq-update-wr_busy_queues-if-needed-on-a-queue-split/20170619-145003
> config: i386-randconfig-x000-201725 (attached as .config)
> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=i386
>
> Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
>
> All warnings (new ones prefixed by >>):
>
> block/bfq-iosched.c: In function 'bfq_get_rq_private':
>>> block/bfq-iosched.c:770:10: warning: 'old_wr_coeff' may be used uninitialized in this function [-Wmaybe-uninitialized]
> else if (old_wr_coeff > 1 && bfqq->wr_coeff == 1)
> ^
> block/bfq-iosched.c:731:15: note: 'old_wr_coeff' was declared here
> unsigned int old_wr_coeff;
> ^~~~~~~~~~~~
>

I'm sending a V2, (probably imperceptibly) slower on average, but not
confusing the compiler.

Thanks,
Paolo

> vim +/old_wr_coeff +770 block/bfq-iosched.c
>
> 754 time_is_before_jiffies(bfqq->last_wr_start_finish +
> 755 bfqq->wr_cur_max_time))) {
> 756 bfq_log_bfqq(bfqq->bfqd, bfqq,
> 757 "resume state: switching off wr");
> 758
> 759 bfqq->wr_coeff = 1;
> 760 }
> 761
> 762 /* make sure weight will be updated, however we got here */
> 763 bfqq->entity.prio_changed = 1;
> 764
> 765 if (likely(!busy))
> 766 return;
> 767
> 768 if (old_wr_coeff == 1 && bfqq->wr_coeff > 1)
> 769 bfqd->wr_busy_queues++;
>> 770 else if (old_wr_coeff > 1 && bfqq->wr_coeff == 1)
> 771 bfqd->wr_busy_queues--;
> 772 }
> 773
> 774 static int bfqq_process_refs(struct bfq_queue *bfqq)
> 775 {
> 776 return bfqq->ref - bfqq->allocated - bfqq->entity.on_st;
> 777 }
> 778
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
> <.config.gz>

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