[PATCH 6/7] s390: mm: accelerate pagefault when badaccess

[Kefeng Wang]

The vm_flags of vma already checked under per-VMA lock, if it is a
bad access, directly handle error and return, there is no need to
lock_mm_and_find_vma() and check vm_flags again.

Signed-off-by: Kefeng Wang <wangkefeng.w...@huawei.com>
---
 arch/s390/mm/fault.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index c421dd44ffbe..162ca2576fd4 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -325,7 +325,8 @@ static void do_exception(struct pt_regs *regs, int access)
                goto lock_mmap;
        if (!(vma->vm_flags & access)) {
                vma_end_read(vma);
-               goto lock_mmap;
+               count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+               return handle_fault_error_nolock(regs, SEGV_ACCERR);
        }
        fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, 
regs);
        if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
-- 
2.27.0