Patch "s390/mm: Fix cmma unused transfer from pgste into pte" has been added to the 4.9-stable tree

Patch "s390/mm: Fix cmma unused transfer from pgste into pte" has been added to the 4.9-stable tree

[gregkh]

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

    s390/mm: Fix cmma unused transfer from pgste into pte

to the 4.9-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:
     s390-mm-fix-cmma-unused-transfer-from-pgste-into-pte.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 0d6da872d3e4a60f43c295386d7ff9a4cdcd57e9 Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Mon, 23 Jan 2017 22:59:44 +0100
Subject: s390/mm: Fix cmma unused transfer from pgste into pte

From: Christian Borntraeger <borntraeger@de.ibm.com>

commit 0d6da872d3e4a60f43c295386d7ff9a4cdcd57e9 upstream.

The last pgtable rework silently disabled the CMMA unused state by
setting a local pte variable (a parameter) instead of propagating it
back into the caller. Fix it.

Fixes: ebde765c0e85 ("s390/mm: uninline ptep_xxx functions from pgtable.h")
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/s390/mm/pgtable.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -202,7 +202,7 @@ static inline pgste_t ptep_xchg_start(st
 	return pgste;
 }
 
-static inline void ptep_xchg_commit(struct mm_struct *mm,
+static inline pte_t ptep_xchg_commit(struct mm_struct *mm,
 				    unsigned long addr, pte_t *ptep,
 				    pgste_t pgste, pte_t old, pte_t new)
 {
@@ -220,6 +220,7 @@ static inline void ptep_xchg_commit(stru
 	} else {
 		*ptep = new;
 	}
+	return old;
 }
 
 pte_t ptep_xchg_direct(struct mm_struct *mm, unsigned long addr,
@@ -231,7 +232,7 @@ pte_t ptep_xchg_direct(struct mm_struct
 	preempt_disable();
 	pgste = ptep_xchg_start(mm, addr, ptep);
 	old = ptep_flush_direct(mm, addr, ptep);
-	ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
+	old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 	preempt_enable();
 	return old;
 }
@@ -246,7 +247,7 @@ pte_t ptep_xchg_lazy(struct mm_struct *m
 	preempt_disable();
 	pgste = ptep_xchg_start(mm, addr, ptep);
 	old = ptep_flush_lazy(mm, addr, ptep);
-	ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
+	old = ptep_xchg_commit(mm, addr, ptep, pgste, old, new);
 	preempt_enable();
 	return old;
 }


Patches currently in stable-queue which might be from borntraeger@de.ibm.com are

queue-4.9/s390-mm-fix-cmma-unused-transfer-from-pgste-into-pte.patch