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Date: Wed, 24 Oct 2018 00:34:59 +0300
From: Igor Stoppa <igor.stoppa@...il.com>
To: Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	Kees Cook <keescook@...omium.org>,
	Matthew Wilcox <willy@...radead.org>,
	Dave Chinner <david@...morbit.com>,
	James Morris <jmorris@...ei.org>,
	Michal Hocko <mhocko@...nel.org>,
	kernel-hardening@...ts.openwall.com,
	linux-integrity@...r.kernel.org,
	linux-security-module@...r.kernel.org
Cc: igor.stoppa@...wei.com,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Jonathan Corbet <corbet@....net>,
	Laura Abbott <labbott@...hat.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Alexey Dobriyan <adobriyan@...il.com>,
	Pekka Enberg <penberg@...nel.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Lihao Liang <lianglihao@...wei.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 12/17] prmem: linked list: set alignment

As preparation to using write rare on the nodes of various types of
lists, specify that the fields in the basic data structures must be
aligned to sizeof(void *)

It is meant to ensure that any static allocation will not cross a page
boundary, to allow pointers to be updated in one step.

Signed-off-by: Igor Stoppa <igor.stoppa@...wei.com>
CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC: Andrew Morton <akpm@...ux-foundation.org>
CC: Masahiro Yamada <yamada.masahiro@...ionext.com>
CC: Alexey Dobriyan <adobriyan@...il.com>
CC: Pekka Enberg <penberg@...nel.org>
CC: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
CC: Lihao Liang <lianglihao@...wei.com>
CC: linux-kernel@...r.kernel.org
---
 include/linux/types.h | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/linux/types.h b/include/linux/types.h
index 9834e90aa010..53609bbdcf0f 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -183,17 +183,29 @@ typedef struct {
 } atomic64_t;
 #endif
 
+#ifdef CONFIG_PRMEM
 struct list_head {
-	struct list_head *next, *prev;
-};
+	struct list_head *next __aligned(sizeof(void *));
+	struct list_head *prev __aligned(sizeof(void *));
+} __aligned(sizeof(void *));
 
-struct hlist_head {
-	struct hlist_node *first;
+struct hlist_node {
+	struct hlist_node *next __aligned(sizeof(void *));
+	struct hlist_node **pprev __aligned(sizeof(void *));
+} __aligned(sizeof(void *));
+#else
+struct list_head {
+	struct list_head *next, *prev;
 };
 
 struct hlist_node {
 	struct hlist_node *next, **pprev;
 };
+#endif
+
+struct hlist_head {
+	struct hlist_node *first;
+};
 
 struct ustat {
 	__kernel_daddr_t	f_tfree;
-- 
2.17.1

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