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 Wed, Dec 13, 2017 at 01:07:02AM -0800, Bryan Tan wrote:

> > > 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.
> 
> Oof, thanks for pointing that out. There's a problem here it seems:
> 0. refcount for a resource is 2 after entering an event handler
> 1. refcount_dec_and_test gets called by the resource destroy
> 2. refcount_dec_and_test gets called by the resource event handler
> 3. resource destroy call checks the condition in wait_event and
>    proceeds to free the resource
> 4. resource event handler calls wake_up() on free'd resource

Yes I agree. I knew it looked funny :)

Please resend

Jason
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