Mastering Linux Kernel Development

Locating a VMA

The find_vma() routine locates the first region in the VMA list that satisfies the condition for a given address (addr < vm_area_struct->vm_end).

/* 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){        struct rb_node *rb_node;        struct vm_area_struct *vma;        /* Check the cache first. */        vma = vmacache_find(mm, addr);        if (likely(vma))               return vma;           rb_node = mm->mm_rb.rb_node;       while (rb_node) {               struct vm_area_struct *tmp;               tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);               if (tmp->vm_end > addr) {                        vma = tmp;                        if (tmp->vm_start <= addr)                                 break;                        rb_node = rb_node->rb_left;               } else                        rb_node = rb_node->rb_right;        }        if (vma) vmacache_update(addr, ...