mm/mmap.c: refine find_vma_prev() with rb_last()

When addr is out of range of the whole rb_tree, pprev will point to the
right-most node.  rb_tree facility already provides a helper function,
rb_last(), to do this task.  We can leverage this instead of
reimplementing it.

This patch refines find_vma_prev() with rb_last() to make it a little
nicer to read.

[akpm@linux-foundation.org: little cleanup, per Vlastimil]
Link: http://lkml.kernel.org/r/20190809001928.4950-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wei Yang 2019-09-23 15:39:25 -07:00 committed by Linus Torvalds
parent 54c95a11cc
commit 73848a9711

View File

@ -2274,12 +2274,9 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
if (vma) {
*pprev = vma->vm_prev;
} else {
struct rb_node *rb_node = mm->mm_rb.rb_node;
*pprev = NULL;
while (rb_node) {
*pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb);
rb_node = rb_node->rb_right;
}
struct rb_node *rb_node = rb_last(&mm->mm_rb);
*pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
}
return vma;
}