1 files changed, 14 insertions, 18 deletions

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index c59a5efa58b..9b436c21195 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -64,6 +64,11 @@ static unsigned long mmap_rnd(void)
 	return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
 }
 
+static unsigned long mmap_base_legacy(void)
+{
+	return TASK_UNMAPPED_BASE + mmap_rnd();
+}
+
 static inline unsigned long mmap_base(void)
 {
 	unsigned long gap = rlimit(RLIMIT_STACK);
@@ -89,29 +94,24 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	 * bit is set, or if the expected stack growth is unlimited:
 	 */
 	if (mmap_is_legacy()) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
+		mm->mmap_base = mmap_base_legacy();
 		mm->get_unmapped_area = arch_get_unmapped_area;
-		mm->unmap_area = arch_unmap_area;
 	} else {
 		mm->mmap_base = mmap_base();
 		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
-		mm->unmap_area = arch_unmap_area_topdown;
 	}
 }
 
 #else
 
-int s390_mmap_check(unsigned long addr, unsigned long len)
+int s390_mmap_check(unsigned long addr, unsigned long len, unsigned long flags)
 {
-	int rc;
-
-	if (!is_compat_task() &&
-	    len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) {
-		rc = crst_table_upgrade(current->mm, 1UL << 53);
-		if (rc)
-			return rc;
-		update_mm(current->mm, current);
-	}
+	if (is_compat_task() || (TASK_SIZE >= (1UL << 53)))
+		return 0;
+	if (!(flags & MAP_FIXED))
+		addr = 0;
+	if ((addr + len) >= TASK_SIZE)
+		return crst_table_upgrade(current->mm, 1UL << 53);
 	return 0;
 }
 
@@ -131,7 +131,6 @@ s390_get_unmapped_area(struct file *filp, unsigned long addr,
 		rc = crst_table_upgrade(mm, 1UL << 53);
 		if (rc)
 			return (unsigned long) rc;
-		update_mm(mm, current);
 		area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
 	}
 	return area;
@@ -154,7 +153,6 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
 		rc = crst_table_upgrade(mm, 1UL << 53);
 		if (rc)
 			return (unsigned long) rc;
-		update_mm(mm, current);
 		area = arch_get_unmapped_area_topdown(filp, addr, len,
 						      pgoff, flags);
 	}
@@ -171,13 +169,11 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
 	 * bit is set, or if the expected stack growth is unlimited:
 	 */
 	if (mmap_is_legacy()) {
-		mm->mmap_base = TASK_UNMAPPED_BASE;
+		mm->mmap_base = mmap_base_legacy();
 		mm->get_unmapped_area = s390_get_unmapped_area;
-		mm->unmap_area = arch_unmap_area;
 	} else {
 		mm->mmap_base = mmap_base();
 		mm->get_unmapped_area = s390_get_unmapped_area_topdown;
-		mm->unmap_area = arch_unmap_area_topdown;
 	}
 }