Re: [PATCH for-rc 4/6] RDMA/vmw_pvrdma: Use refcount_dec_and_test to avoid warning

[Jason Gunthorpe <jgg-uk2M96/98Pc@public.gmane.org>]

On Tue, Dec 12, 2017 at 04:08:16PM -0800, Bryan Tan wrote:
> On Tue, Dec 12, 2017 at 11:55:30AM -0700, Jason Gunthorpe wrote:

> Hm, it's still not clear to me what expectations are not followed here,
> and how you're differentiating 'refcount' from 'usecnt'.

A refcount is something that has exactly one 'refcount_dec_and_test'
that then goes on to 'free' the thing being refcountedt. It never has
a wait queue.

A usecnt is something that has an async path that waits for all users
to stop using it then 'frees' it. It always includes a wait
queue.

> And not that it makes it right, but I did notice that mlx4 uses the
> same pattern as what I've done here [1].

Ah, this is good, I was trying to find something like it. Kees
approves so I have no problem taking your patch.

Though you might want to reflect on if using a completion is better
than a wait_event.. Not immediately clear to me.

Jason
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