Re: [PATCH V2 5/6] blk-mq: prepare for implementing hctx table via xarray

[Ming Lei <ming.lei@redhat.com>]

On Thu, Mar 03, 2022 at 05:08:47PM +0800, kernel test robot wrote:
> Hi Ming,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on axboe-block/for-next]
> [also build test WARNING on v5.17-rc6 next-20220302]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Ming-Lei/blk-mq-update_nr_hw_queues-related-improvement-bugfix/20220302-201636
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
> config: m68k-randconfig-m031-20220302 (https://download.01.org/0day-ci/archive/20220303/202203031651.z0z86F6E-lkp@intel.com/config)
> compiler: m68k-linux-gcc (GCC) 11.2.0
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> smatch warnings:
> block/blk-mq-sysfs.c:282 __blk_mq_register_dev() warn: always true condition '(--i >= 0) => (0-u32max >= 0)'
> block/blk-mq-sysfs.c:282 __blk_mq_register_dev() warn: always true condition '(--i >= 0) => (0-u32max >= 0)'

Good catch, will fix it by the following way in V3:

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 6a7fb960e046..851faacc2f78 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -279,8 +279,8 @@ int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
        return ret;

 unreg:
-       while (--i >= 0)
-               blk_mq_unregister_hctx(xa_load(&q->hctx_table, i));
+       queue_for_each_hw_ctx(q, hctx, i) {
+               blk_mq_unregister_hctx(hctx);

        kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
        kobject_del(q->mq_kobj);



Thanks,
Ming