From 7b2d55d2c8961ae9d456d3133f4ae2f0fbd3e14f Mon Sep 17 00:00:00 2001
From: Jérôme Glisse <jglisse@redhat.com>
Date: Fri, 8 Sep 2017 16:11:46 -0700
Subject: mm/ZONE_DEVICE: special case put_page() for device private pages
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A ZONE_DEVICE page that reach a refcount of 1 is free ie no longer have
any user.  For device private pages this is important to catch and thus we
need to special case put_page() for this.

Link: http://lkml.kernel.org/r/20170817000548.32038-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/hmm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'mm')

diff --git a/mm/hmm.c b/mm/hmm.c
index f6c745b9a25ae..3c6265d4254b1 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -25,9 +25,17 @@
 #include <linux/sched.h>
 #include <linux/swapops.h>
 #include <linux/hugetlb.h>
+#include <linux/jump_label.h>
 #include <linux/mmu_notifier.h>
 
 
+/*
+ * Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h
+ */
+DEFINE_STATIC_KEY_FALSE(device_private_key);
+EXPORT_SYMBOL(device_private_key);
+
+
 #ifdef CONFIG_HMM
 static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
 
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