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authorMiaohe Lin <linmiaohe@huawei.com>2021-02-24 12:04:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:30 -0800
commit374437a274e24e8e3ccd19f704e80d325f75f254 (patch)
tree34b0338bbb860de6c1aa4434f567722debd41cb0 /mm
parentc045c72ccde3a267963f8e85f388db4c40dea3b3 (diff)
mm/pgtable-generic.c: optimize the VM_BUG_ON condition in pmdp_huge_clear_flush()
The developer will have trouble figuring out why the BUG actually triggered when there is a complex expression in the VM_BUG_ON. Because we can only identify the condition triggered BUG via line number provided by VM_BUG_ON. Optimize this by spliting such a complex expression into two simple conditions. Link: https://lkml.kernel.org/r/20210203084137.25522-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Suggested-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>
Diffstat (limited to 'mm')
-rw-r--r--mm/pgtable-generic.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index fa1375f3e3b2..c2210e1cdb51 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -135,8 +135,9 @@ 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)));
+ VM_BUG_ON(!pmd_present(*pmdp));
+ /* Below assumes pmd_present() is true */
+ VM_BUG_ON(!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;