linux-kernel - [4.2.y-ckt stable] Patch "MIPS: Handle highmem pages in __update_cache" has been added to the 4.2.y-ckt tree

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Date:	Thu,  9 Jun 2016 07:35:05 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	Paul Burton <paul.burton@...tec.com>
Cc:	Lars Persson <lars.persson@...s.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jerome Marchand <jmarchan@...hat.com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org,
	Ralf Baechle <ralf@...ux-mips.org>,
	Kamal Mostafa <kamal@...onical.com>,
	kernel-team@...ts.ubuntu.com
Subject: [4.2.y-ckt stable] Patch "MIPS: Handle highmem pages in __update_cache" has been added to the 4.2.y-ckt tree

This is a note to let you know that I have just added a patch titled

    MIPS: Handle highmem pages in __update_cache

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 583490f1157a28699ea9b992d78e78c009527f53 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@...tec.com>
Date: Tue, 1 Mar 2016 02:37:58 +0000
Subject: MIPS: Handle highmem pages in __update_cache

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.

Signed-off-by: Paul Burton <paul.burton@...tec.com>
Cc: Lars Persson <lars.persson@...s.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Jerome Marchand <jmarchan@...hat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Cc: linux-mips@...ux-mips.org
Cc: linux-kernel@...r.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12721/
Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 arch/mips/mm/cache.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index aab218c..0d71fdd 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -143,9 +143,17 @@ 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);
 	}
 }
--
2.7.4