pgprot2cachemode
enum page_cache_mode pgprot2cachemode(pgprot_t pgprot);
if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
pgprot2cachemode(prot),
enum page_cache_mode want_pcm = pgprot2cachemode(*vma_prot);
cache = !!pgprot2cachemode(mask_set);