The presence of struct page does not guarantee linear mapping for the pfn physical range. Device private memory which is non-coherent is excluded from linear mapping during devm_memremap_pages() though they will still have struct page coverage. Just check for device private memory before giving out virtual address for a given pfn.
Signed-off-by: Anshuman Khandual <[email protected]> --- All these helper functions are all pfn_t related but could not figure out another way of determining a private pfn without looking into it's struct page. pfn_t_to_virt() is not getting used any where in mainline kernel.Is it used by out of tree drivers ? Should we then drop it completely ? include/linux/pfn_t.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h index 7bb7785..3c202a1 100644 --- a/include/linux/pfn_t.h +++ b/include/linux/pfn_t.h @@ -68,7 +68,7 @@ static inline phys_addr_t pfn_t_to_phys(pfn_t pfn) static inline void *pfn_t_to_virt(pfn_t pfn) { - if (pfn_t_has_page(pfn)) + if (pfn_t_has_page(pfn) && !is_device_private_page(pfn_t_to_page(pfn))) return __va(pfn_t_to_phys(pfn)); return NULL; } -- 2.7.4
