Both find_vma and find_vma_prev have code for walking rb tree, and we can walk less.
To cut the walk in find_vma_prev off, find_vma is changed to take care of vm_prev while walking rb tree, and we end up wrapping find_vma_prev with find_vma. btw, what happened to LKML? Signed-off-by: Hillf Danton <[email protected]> --- --- a/mm/mmap.c Fri Aug 3 07:38:10 2012 +++ b/mm/mmap.c Mon Aug 6 20:10:18 2012 @@ -1602,11 +1602,18 @@ get_unmapped_area(struct file *file, uns EXPORT_SYMBOL(get_unmapped_area); -/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ -struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) +/* + * Look up the first VMA which satisfies addr < vm_end, NULL if none. + * Also return a pointer to the previous VMA. + */ +struct vm_area_struct * +find_vma_prev(struct mm_struct *mm, unsigned long addr, + struct vm_area_struct **pprev) { struct vm_area_struct *vma = NULL; + *pprev = NULL; /* Should be removed with WARN_ON_ONCE(!mm) */ + if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */ return NULL; @@ -1630,39 +1637,29 @@ struct vm_area_struct *find_vma(struct m if (vma_tmp->vm_start <= addr) break; rb_node = rb_node->rb_left; - } else + } else { rb_node = rb_node->rb_right; + *pprev = vma_tmp; + } } - if (vma) + if (vma) { mm->mmap_cache = vma; + /* remove false positive produced while walking rb tree */ + *pprev = vma->vm_prev; + } + } else { + *pprev = vma->vm_prev; } return vma; } -EXPORT_SYMBOL(find_vma); - -/* - * Same as find_vma, but also return a pointer to the previous VMA in *pprev. - */ -struct vm_area_struct * -find_vma_prev(struct mm_struct *mm, unsigned long addr, - struct vm_area_struct **pprev) +struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) { - struct vm_area_struct *vma; + struct vm_area_struct *prev; - vma = find_vma(mm, 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; - } - } - return vma; + return find_vma_prev(mm, addr, &prev); } +EXPORT_SYMBOL(find_vma); /* * Verify that the stack growth is acceptable and -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
