[PATCH] s390/mm: return -ENOMEM in arch_get_unmapped_area[_topdown]

[Li Wang]

That would be very hard to get -ENOMEM returned in crst_table_upgrade()
because the condition(addr + len <= TASK_SIZE) makes all 'end' value
is smaller/equal than 'TASK_SIZE_TASK'. So let's move it to the upper
layer.

Fixes: 8ab867cb0806 (s390/mm: fix BUG_ON in crst_table_upgrade)
Signed-off-by: Li Wang <liw...@redhat.com>
---
 arch/s390/mm/mmap.c    | 6 ++++++
 arch/s390/mm/pgalloc.c | 3 +--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 5bea139..8ddb13a 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -119,6 +119,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long 
addr,
                return addr;
 
 check_asce_limit:
+       if (addr + len >= TASK_SIZE_MAX)
+               return -ENOMEM;
+
        if (addr + len > current->mm->context.asce_limit &&
            addr + len <= TASK_SIZE) {
                rc = crst_table_upgrade(mm, addr + len);
@@ -184,6 +187,9 @@ arch_get_unmapped_area_topdown(struct file *filp, const 
unsigned long addr0,
        }
 
 check_asce_limit:
+       if (addr + len >= TASK_SIZE_MAX)
+               return -ENOMEM;
+
        if (addr + len > current->mm->context.asce_limit &&
            addr + len <= TASK_SIZE) {
                rc = crst_table_upgrade(mm, addr + len);
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 05f1f27..5e4b887 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -84,8 +84,7 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long 
end)
 
        /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
        VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE);
-       if (end >= TASK_SIZE_MAX)
-               return -ENOMEM;
+
        rc = 0;
        notify = 0;
        while (mm->context.asce_limit < end) {
-- 
2.9.3