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    SubjectRe: [PATCH v8 3.2.0-rc5 1/9] uprobes: Install and remove breakpoints.
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    On Fri, 2011-12-16 at 17:58 +0530, Srikar Dronamraju wrote:
    > +static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
    > +{
    > + struct list_head try_list;
    > + struct vm_area_struct *vma;
    > + struct address_space *mapping;
    > + struct vma_info *vi, *tmpvi;
    > + struct mm_struct *mm;
    > + loff_t vaddr;
    > + int ret = 0;
    > +
    > + mapping = uprobe->inode->i_mapping;
    > + INIT_LIST_HEAD(&try_list);
    > + while ((vi = find_next_vma_info(&try_list, uprobe->offset,
    > + mapping, is_register)) != NULL) {
    > + if (IS_ERR(vi)) {
    > + ret = PTR_ERR(vi);
    > + break;
    > + }
    > + mm = vi->mm;
    > + down_read(&mm->mmap_sem);
    > + vma = find_vma(mm, (unsigned long)vi->vaddr);
    > + if (!vma || !valid_vma(vma, is_register)) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > + vaddr = vma_address(vma, uprobe->offset);
    > + if (vma->vm_file->f_mapping->host != uprobe->inode ||
    > + vaddr != vi->vaddr) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > +
    > + if (is_register)
    > + ret = install_breakpoint(mm, uprobe, vma, vi->vaddr);
    > + else
    > + remove_breakpoint(mm, uprobe, vi->vaddr);
    > +
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + if (is_register) {
    > + if (ret && ret == -EEXIST)
    > + ret = 0;
    > + if (ret)
    > + break;
    > + }

    Since you init ret := 0 and remove_breakpoint doesn't change it, this
    conditional on is_register is superfluous.

    > + }
    > + list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + }
    > + return ret;
    > +}


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