Re: [v2] powerpc/mm/cxl: Add barrier when setting mm cpumask

On Mon, 2017-08-28 at 08:35:44 UTC, "Aneesh Kumar K.V" wrote:

We need to add memory barrier so that the page table walk doesn't happen
before the cpumask is set and made visible to the other cpus. We need
to use a sync here instead of lwsync because lwsync is not sufficient for
store/load ordering.

We also need to add an if (mm) check so that we do the right thing when called
with a kernel context. For kernel context, we have mm = NULL. W.r.t kernel
address we can skip setting the mm cpumask.

Fixes: 0f4bc0932e ("powerpc/mm/cxl: Add the fault handling cpu to mm cpumask")
Cc: Andrew Donnellan <redacted>
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Dan Carpenter <redacted>
Signed-off-by: Aneesh Kumar K.V <redacted>
Acked-by: Andrew Donnellan <redacted>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/22259a6e800cdb8e06e65432fcd019

cheers