mm/nvdimm: add is_ioremap_addr and use that to check ioremap address

Architectures like powerpc use different address range to map ioremap
and vmalloc range.  The memunmap() check used by the nvdimm layer was
wrongly using is_vmalloc_addr() to check for ioremap range which fails
for ppc64.  This result in ppc64 not freeing the ioremap mapping.  The
side effect of this is an unbind failure during module unload with
papr_scm nvdimm driver

Link: http://lkml.kernel.org/r/20190701134038.14165-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Fixes: b5beae5e22 ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/include/asm/pgtable.h

@@ -140,6 +140,20 @@ static inline void pte_frag_set(mm_context_t *ctx, void *p)
 }
 #endif
 
+#ifdef CONFIG_PPC64
+#define is_ioremap_addr is_ioremap_addr
+static inline bool is_ioremap_addr(const void *x)
+{
+#ifdef CONFIG_MMU
+	unsigned long addr = (unsigned long)x;
+
+	return addr >= IOREMAP_BASE && addr < IOREMAP_END;
+#else
+	return false;
+#endif
+}
+#endif /* CONFIG_PPC64 */
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_PGTABLE_H */