hi,

> > > > i believe it's a problem in xbd, not in vnd.
> > > > doing vnode operations from interrupt context is evil.
> > > 
> > > Yes, but it's vnd that is doing those from interrupt context.
> > 
> > xbd does VOP_STRATEGY.  it's the root of the problem in this PR.
> 
> It does VOP_STRATEGY() against a vnode which points to a device, so
> it should be the same as DEV_STRATEGY(), isn't it ?
> 
> When xbd points to a vnd, it will call vndstrategy() from interrupt
> context (though VOP_STRATEGY() on a vnode pointing to /dev/vnd0?).

yes, it's how the current code works.
it doesn't mean you can use VOP_STRATEGY from interrupt context, though.

> This is what this PR is about.

i don't think so.
you shouldn't expect VOP_STRATEGY from interrupt context work.
how vnd is implemented is a different topic.
(thanks for fixing a longstanding vnd bug, btw.)

YAMAMOTO Takashi