diff options
| author | Miaohe Lin <linmiaohe@huawei.com> | 2021-02-24 12:04:39 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-24 13:38:30 -0800 |
| commit | 374437a274e24e8e3ccd19f704e80d325f75f254 (patch) | |
| tree | 34b0338bbb860de6c1aa4434f567722debd41cb0 | |
| parent | c045c72ccde3a267963f8e85f388db4c40dea3b3 (diff) | |
| download | linux-374437a274e24e8e3ccd19f704e80d325f75f254.tar.bz2 | |
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>
| -rw-r--r-- | mm/pgtable-generic.c | 5 |
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; |