From: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> Subject: mm/mmap: not necessary to check mapping separately *root* with type of struct rb_root_cached is an element of *mapping* with type of struct address_space. This implies when we have a valid *root* it must be a part of valid *mapping*. So we can merge these two checks together to make the code more easy to read and to save some cpu cycles. Link: https://lkml.kernel.org/r/20200913133631.37781-1-richard.weiyang@xxxxxxxxxxxxxxxxx Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/mm/mmap.c~mm-mmap-not-necessary-to-check-mapping-separately +++ a/mm/mmap.c @@ -895,10 +895,9 @@ again: anon_vma_interval_tree_post_update_vma(next); anon_vma_unlock_write(anon_vma); } - if (mapping) - i_mmap_unlock_write(mapping); if (root) { + i_mmap_unlock_write(mapping); uprobe_mmap(vma); if (adjust_next) _
