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    SubjectRe: [PATCH v7 3.2-rc2 3/30] uprobes: register/unregister probes.
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    Date
    On Fri, 2011-11-18 at 16:37 +0530, Srikar Dronamraju wrote:
    > +static int __register_uprobe(struct inode *inode, loff_t offset,
    > + struct uprobe *uprobe)
    > +{
    > + 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 = inode->i_mapping;
    > + INIT_LIST_HEAD(&try_list);
    > + while ((vi = find_next_vma_info(&try_list, offset,
    > + mapping, true)) != NULL) {
    > + if (IS_ERR(vi)) {
    > + ret = -ENOMEM;
    > + break;
    > + }
    > + mm = vi->mm;
    > + down_read(&mm->mmap_sem);
    > + vma = find_vma(mm, (unsigned long)vi->vaddr);
    > + if (!vma || !valid_vma(vma, true)) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > + vaddr = vma->vm_start + offset;
    > + vaddr -= vma->vm_pgoff << PAGE_SHIFT;
    > + if (vma->vm_file->f_mapping->host != inode ||
    > + vaddr != vi->vaddr) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > + ret = install_breakpoint(mm);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + if (ret && ret == -EEXIST)
    > + ret = 0;
    > + if (!ret)
    > + break;
    > + }
    > + list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + }
    > + return ret;
    > +}
    > +
    > +static void __unregister_uprobe(struct inode *inode, loff_t offset,
    > + struct uprobe *uprobe)
    > +{
    > + struct list_head try_list;
    > + struct address_space *mapping;
    > + struct vma_info *vi, *tmpvi;
    > + struct vm_area_struct *vma;
    > + struct mm_struct *mm;
    > + loff_t vaddr;
    > +
    > + mapping = inode->i_mapping;
    > + INIT_LIST_HEAD(&try_list);
    > + while ((vi = find_next_vma_info(&try_list, offset,
    > + mapping, false)) != NULL) {
    > + if (IS_ERR(vi))
    > + break;
    > + mm = vi->mm;
    > + down_read(&mm->mmap_sem);
    > + vma = find_vma(mm, (unsigned long)vi->vaddr);
    > + if (!vma || !valid_vma(vma, false)) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > + vaddr = vma->vm_start + offset;
    > + vaddr -= vma->vm_pgoff << PAGE_SHIFT;
    > + if (vma->vm_file->f_mapping->host != inode ||
    > + vaddr != vi->vaddr) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + continue;
    > + }
    > + remove_breakpoint(mm);
    > + up_read(&mm->mmap_sem);
    > + mmput(mm);
    > + }
    > +
    > + list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
    > + list_del(&vi->probe_list);
    > + kfree(vi);
    > + }
    > + delete_uprobe(uprobe);
    > +}

    I already mentioned on IRC that there's a lot of duplication here and
    how to 'solve that'...

    Something like the below, it lost the delete_uprobe() bit, and it adds a
    few XXX marks where we have to deal with -ENOMEM. Also its not been near
    a compiler.

    ---
    kernel/uprobes.c | 78 ++++++++++++++---------------------------------------
    1 files changed, 21 insertions(+), 57 deletions(-)

    diff --git a/kernel/uprobes.c b/kernel/uprobes.c
    index 2493191..c57284a 100644
    --- a/kernel/uprobes.c
    +++ b/kernel/uprobes.c
    @@ -622,7 +622,7 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
    }

    static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
    - loff_t vaddr)
    + struct vm_area_struct *vma, loff_t vaddr)
    {
    if (!set_orig_insn(mm, uprobe, (unsigned long)vaddr, true))
    atomic_dec(&mm->mm_uprobes_count);
    @@ -713,8 +713,10 @@ static struct vma_info *find_next_vma_info(struct list_head *head,
    return retvi;
    }

    -static int __register_uprobe(struct inode *inode, loff_t offset,
    - struct uprobe *uprobe)
    +typedef int (*vma_func_t)(struct mm_struct *mm, struct uprobe *uprobe,
    + struct vm_area_struct *vma, unsigned long addr);
    +
    +static int __for_each_vma(struct uprobe *uprobe, vma_func_t func)
    {
    struct list_head try_list;
    struct vm_area_struct *vma;
    @@ -724,12 +726,12 @@ static int __register_uprobe(struct inode *inode, loff_t offset,
    loff_t vaddr;
    int ret = 0;

    - mapping = inode->i_mapping;
    + mapping = uprobe->inode->i_mapping;
    INIT_LIST_HEAD(&try_list);
    - while ((vi = find_next_vma_info(&try_list, offset,
    + while ((vi = find_next_vma_info(&try_list, uprobe->offset,
    mapping, true)) != NULL) {
    if (IS_ERR(vi)) {
    - ret = -ENOMEM;
    + ret = PTR_ERR(vi);
    break;
    }
    mm = vi->mm;
    @@ -742,9 +744,9 @@ static int __register_uprobe(struct inode *inode, loff_t offset,
    mmput(mm);
    continue;
    }
    - vaddr = vma->vm_start + offset;
    + vaddr = vma->vm_start + uprobe->offset;
    vaddr -= vma->vm_pgoff << PAGE_SHIFT;
    - if (vma->vm_file->f_mapping->host != inode ||
    + if (vma->vm_file->f_mapping->host != uprobe->inode ||
    vaddr != vi->vaddr) {
    list_del(&vi->probe_list);
    kfree(vi);
    @@ -752,12 +754,12 @@ static int __register_uprobe(struct inode *inode, loff_t offset,
    mmput(mm);
    continue;
    }
    - ret = install_breakpoint(mm, uprobe, vma, vi->vaddr);
    + ret = func(mm, uprobe, vma, vi->vaddr);
    up_read(&mm->mmap_sem);
    mmput(mm);
    if (ret && ret == -EEXIST)
    ret = 0;
    - if (!ret)
    + if (ret)
    break;
    }
    list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
    @@ -767,52 +769,14 @@ static int __register_uprobe(struct inode *inode, loff_t offset,
    return ret;
    }

    -static void __unregister_uprobe(struct inode *inode, loff_t offset,
    - struct uprobe *uprobe)
    +static int __register_uprobe(struct uprobe *uprobe)
    {
    - struct list_head try_list;
    - struct address_space *mapping;
    - struct vma_info *vi, *tmpvi;
    - struct vm_area_struct *vma;
    - struct mm_struct *mm;
    - loff_t vaddr;
    -
    - mapping = inode->i_mapping;
    - INIT_LIST_HEAD(&try_list);
    - while ((vi = find_next_vma_info(&try_list, offset,
    - mapping, false)) != NULL) {
    - if (IS_ERR(vi))
    - break;
    - mm = vi->mm;
    - down_read(&mm->mmap_sem);
    - vma = find_vma(mm, (unsigned long)vi->vaddr);
    - if (!vma || !valid_vma(vma, false)) {
    - list_del(&vi->probe_list);
    - kfree(vi);
    - up_read(&mm->mmap_sem);
    - mmput(mm);
    - continue;
    - }
    - vaddr = vma->vm_start + offset;
    - vaddr -= vma->vm_pgoff << PAGE_SHIFT;
    - if (vma->vm_file->f_mapping->host != inode ||
    - vaddr != vi->vaddr) {
    - list_del(&vi->probe_list);
    - kfree(vi);
    - up_read(&mm->mmap_sem);
    - mmput(mm);
    - continue;
    - }
    - remove_breakpoint(mm, uprobe, vi->vaddr);
    - up_read(&mm->mmap_sem);
    - mmput(mm);
    - }
    + return __for_each_vma(uprobe, install_breakpoint);
    +}

    - list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
    - list_del(&vi->probe_list);
    - kfree(vi);
    - }
    - delete_uprobe(uprobe);
    +static int __unregister_uprobe(struct uprobe *uprobe)
    +{
    + return __for_each_vma(uprobe, remove_breakpoint);
    }

    /*
    @@ -852,10 +816,10 @@ int register_uprobe(struct inode *inode, loff_t offset,
    mutex_lock(uprobes_hash(inode));
    uprobe = alloc_uprobe(inode, offset);
    if (uprobe && !add_consumer(uprobe, consumer)) {
    - ret = __register_uprobe(inode, offset, uprobe);
    + ret = __register_uprobe(uprobe);
    if (ret) {
    uprobe->consumers = NULL;
    - __unregister_uprobe(inode, offset, uprobe);
    + __unregister_uprobe(uprobe); // -ENOMEM
    } else
    uprobe->flags |= UPROBES_RUN_HANDLER;
    }
    @@ -894,7 +858,7 @@ void unregister_uprobe(struct inode *inode, loff_t offset,
    }

    if (!uprobe->consumers) {
    - __unregister_uprobe(inode, offset, uprobe);
    + __unregister_uprobe(uprobe); // XXX -ENOMEM
    uprobe->flags &= ~UPROBES_RUN_HANDLER;
    }
    mutex_unlock(uprobes_hash(inode));


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      Last update: 2011-12-01 14:23    [W:0.038 / U:0.508 seconds]
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