Re: [PATCH] Pass mode to wait_on_atomic_t() action funcs and provide default actions

[David Howells <dhowells@redhat.com>]

Peter Zijlstra <peterz@infradead.org> wrote:

> > The moment atomic_dec_and_test() is called, *net is at liberty to disappear,
> > so there's no way to find a waitqueue - unless that waitqueue is guaranteed
> > not to be deallocated, eg. by being global.
> 
> But any possible wait side will still need to dereference *net at an
> indeterminate point in the future to ascertain the value does now indeed
> read 0.

Yeah, the assumption is that the *wait* side is where the deallocation is
happening.  So I have something like:

	net->live = false; // Tell the cell managers to delete the cells
	...
	foreach (cell)
		queue_work(cell);
	...
	wait_on_atomic_t(&net->cells_outstanding, atomic_t_wait,
			 TASK_UNINTERRUPTIBLE);
	...
	destroy(net);

> ... We can certainly start with your patch, as that does clean things up.

Can I put that down as a Grudgingly-acked-by?

David