Re: [PATCH 17/17] null_blk: remove legacy IO path

Jens Axboe
2018-10-12T17:30:06Z

On 10/12/18 11:24 AM, Sébastien Boisvert wrote:
>> + if (g_queue_mode == NULL_Q_RQ) {
>> + pr_err("null_blk: legacy IO path no longer available\n");
>> + return -EINVAL;
>> + }
>
> Is this the only location where the value NULL_Q_RQ has be checked ?

I've since fixed a few more, all should be well now. The updated version
is here:

http://git.kernel.dk/cgit/linux-block/commit/?h=mq-conversions&id=d6fd3bd94a7333a8cd0bf7ef18f719ef7e052dc4

> Since the enum that contains NULL_Q_RQ is in
> drivers/block/null_blk_main.c, and not in a linux header file, would
> it be thinkable to remove NULL_Q_RQ from the enum too, and not adding
> this legacy check ?
>
> Would that break user space (the number one rule) ?

It wouldn't break user space. In any case, if someone is currently using
queue_mode=1, it'd fail to load after this patch.

I'm checking that at the bottom, we could remove NULL_Q_RQ if we just
made that check == 1 instead. But cleaner to keep it, imho.

--
Jens Axboe