s390/pgtable: Use set_pmd_bit() to invalidate PMD entry

Commit 3a5a8d3 ("mm: fix race between __split_huge_pmd_locked()
and GUP-fast") failed to follow the convention and used direct PMD
entry modification instead of set_pmd_bit().

Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/r/a9248694a38cc898d3f0628f59b8abb57d56a416.1772812343.git.agordeev@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: Alexander Gordeev

arch/s390/include/asm/pgtable.h

@@ -1744,10 +1744,10 @@ static inline pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma,
 static inline pmd_t pmdp_invalidate(struct vm_area_struct *vma,
 				   unsigned long addr, pmd_t *pmdp)
 {
-	pmd_t pmd;
+	pmd_t pmd = *pmdp;
 
-	VM_WARN_ON_ONCE(!pmd_present(*pmdp));
-	pmd = __pmd(pmd_val(*pmdp) | _SEGMENT_ENTRY_INVALID);
+	VM_WARN_ON_ONCE(!pmd_present(pmd));
+	pmd = set_pmd_bit(pmd, __pgprot(_SEGMENT_ENTRY_INVALID));
 	return pmdp_xchg_direct(vma->vm_mm, addr, pmdp, pmd);
 }