[PATCH v5 1/7] pmem: add wb_cache_pmem() to the PMEM API

[Andrew Morton]

On Fri, 18 Dec 2015 22:22:14 -0700 Ross Zwisler <ross.zwisler at linux.intel.com> wrote:

> The function __arch_wb_cache_pmem() was already an internal implementation
> detail of the x86 PMEM API, but this functionality needs to be exported as
> part of the general PMEM API to handle the fsync/msync case for DAX mmaps.
> 
> One thing worth noting is that we really do want this to be part of the
> PMEM API as opposed to a stand-alone function like clflush_cache_range()
> because of ordering restrictions.  By having wb_cache_pmem() as part of the
> PMEM API we can leave it unordered, call it multiple times to write back
> large amounts of memory, and then order the multiple calls with a single
> wmb_pmem().
> 
> @@ -138,7 +139,7 @@ static inline void arch_clear_pmem(void __pmem *addr, size_t size)
>  	else
>  		memset(vaddr, 0, size);
>  
> -	__arch_wb_cache_pmem(vaddr, size);
> +	arch_wb_cache_pmem(addr, size);
>  }
>  

reject.  I made this

	arch_wb_cache_pmem(vaddr, size);

due to Dan's
http://www.ozlabs.org/~akpm/mmots/broken-out/pmem-dax-clean-up-clear_pmem.patch