On 2018-10-12 01:30 PM, Jens Axboe wrote:

On 10/12/18 11:24 AM, Sébastien Boisvert wrote:

quoted

quoted

+	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

quoted

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.

Just curious, where can this be passed (mount option, boot option, /sys, /proc, driver code, or whatnot) ?

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.

I agree, if queue_mode=1 can be passed.


Reviewed-by: Sébastien Boisvert <redacted>