[PATCH 05/16] S390: use ACCESS_ONCE for rlimits

[Jiri Slaby]

Make sure compiler won't do weird things with limits. E.g. fetching
them twice may return 2 different values after writable limits are
implemented.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux390@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
---
 arch/s390/mm/mmap.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index f4558cc..90d3216 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -40,7 +40,8 @@
 
 static inline unsigned long mmap_base(void)
 {
-	unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
+	unsigned long gap = ACCESS_ONCE(current->signal->
+			rlim[RLIMIT_STACK].rlim_cur);
 
 	if (gap < MIN_GAP)
 		gap = MIN_GAP;
@@ -59,9 +60,11 @@ static inline int mmap_is_legacy(void)
 	if (!is_compat_task())
 		return 1;
 #endif
+	if (ACCESS_ONCE(current->signal->rlim[RLIMIT_STACK].rlim_cur) ==
+			RLIM_INFINITY)
+		return 1;
 	return sysctl_legacy_va_layout ||
-	    (current->personality & ADDR_COMPAT_LAYOUT) ||
-	    current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY;
+	    (current->personality & ADDR_COMPAT_LAYOUT);
 }
 
 #ifndef CONFIG_64BIT
-- 
1.6.4.2

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