Patch "MIPS: Handle highmem pages in __update_cache" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

MIPS: Handle highmem pages in __update_cache

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mips-handle-highmem-pages-in-__update_cache.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Paul Burton <[email protected]>
Date: Tue, 1 Mar 2016 02:37:58 +0000
Subject: MIPS: Handle highmem pages in __update_cache

From: Paul Burton <[email protected]>

commit f4281bba818105c7c91799abe40bc05c0dbdaa25 upstream.

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.

Patchwork: https://patchwork.linux-mips.org/patch/12721/

---
 arch/mips/mm/cache.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

@@ -143,9 +143,17 @@ void __update_cache(struct vm_area_struc
 		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);
 	}
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/mips-disable-preemption-during-prctl-pr_set_fp_mode.patch queue-4.5/mips-fix-sigreturn-via-vdso-on-micromips-kernel.patch queue-4.5/mips-handle-highmem-pages-in-__update_cache.patch queue-4.5/mips-fix-watchpoint-restoration.patch queue-4.5/mips-build-micromips-vdso-for-micromips-kernels.patch queue-4.5/mips-math-emu-fix-jalr-emulation-when-rd-0.patch queue-4.5/mips-sync-icache-dcache-in-set_pte_at.patch queue-4.5/mips-fix-msa-ld_-st_-asm-macros-to-use-ptr_addu.patch queue-4.5/mips-prevent-restoration-of-msa-context-in-non-msa-kernels.patch queue-4.5/mips-use-copy_s.fmt-rather-than-copy_u.fmt.patch