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

[Michael Ellerman]

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 <andrew.donnellan at au1.ibm.com>
> Reported-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
> Acked-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

Applied to powerpc next, thanks.

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

cheers