mm/pgtable-generic.c: simplify the VM_BUG_ON condition in pmdp_huge_clear_flush()

The condition (A && !C && !D) || !A is equivalent to !A || (A && !C && !D)
and can be further simplified to !A || (!C && !D).

Link: https://lkml.kernel.org/r/20210201114319.34720-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 9578db8..fa1375f 100644 (file)
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -135,8 +135,8 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 {
        pmd_t pmd;
        VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-       VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
-                          !pmd_devmap(*pmdp)) || !pmd_present(*pmdp));
+       VM_BUG_ON(!pmd_present(*pmdp) || (!pmd_trans_huge(*pmdp) &&
+                                         !pmd_devmap(*pmdp)));
        pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
        flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
        return pmd;