MIPS: Handle highmem pages in __update_cache

The following patch will expose __update_cache to highmem pages. Handle
them by mapping them in for the duration of the cache maintenance, just
like in __flush_dcache_page. The code for that isn't shared because we
need the page address in __update_cache so sharing became messy. Given
that the entirity is an extra 5 lines, just duplicate it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable <stable@vger.kernel.org> # v4.1+
Patchwork: https://patchwork.linux-mips.org/patch/12721/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index 5a67d8c3decb70931bac99f6eb09d36b9d742acb..8befa55234dff2feaffc48243f11a4370bfcc447 100644 (file)
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -149,9 +149,17 @@ void __update_cache(struct vm_area_struct *vma, unsigned long address,
                return;
        page = pfn_to_page(pfn);
        if (page_mapping(page) && Page_dcache_dirty(page)) {
-               addr = (unsigned long) page_address(page);
+               if (PageHighMem(page))
+                       addr = (unsigned long)kmap_atomic(page);
+               else
+                       addr = (unsigned long)page_address(page);
+
                if (exec || pages_do_alias(addr, address & PAGE_MASK))
                        flush_data_cache_page(addr);
+
+               if (PageHighMem(page))
+                       __kunmap_atomic((void *)addr);
+
                ClearPageDcacheDirty(page);
        }
 }