Re: [PATCH] null_blk: add zoned config support information

John Pittman
2019-01-04T20:37:28Z

Thanks Bart; I made the changes and sent them in as a v2, I'm sure you
already saw. I have a quick, unrelated question if you have a moment.
In testing the null_blk driver, I found that trim commands sent by fio
were rejected due to lack of support. Tracking down Shaohua's commit
306eb6b4a ("nullb: support discard"), he mentions that "discard makes
sense for memory backed disk". Just to see what would happen, I
edited the source to make discard a configurable parameter at
modprobe, and after the edit & build, the trim commands submitted
fine. Does this sort of change make sense? I mean the ability to do
discard to null_blk without it being memory backed; solely for
testing/benchmarking purposes. I haven't found any good instructions
on creating a memory backed or discard enabled null_blk device from
the command line, so I assume a higher level driver would have to hook
in and enable these features manually. Thanks for your time and any
information.
John

On Fri, Jan 4, 2019 at 11:47 AM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On Fri, 2019-01-04 at 10:42 -0500, John Pittman wrote:
> > static inline int null_zone_init(struct nullb_device *dev)
> > {
> > + pr_info("CONFIG_BLK_DEV_ZONED not enabled\n");
> > return -EINVAL;
> > }
>
> Have you considered to use pr_err() instead of pr_info()?
>
> Thanks,
>
> Bart.