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    Subject[PATCH v4 48/66] fork: Use VMA iterator
    Date
    From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

    The VMA iterator is faster than the linked list and removing the linked
    list will shrink the vm_area_struct.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
    ---
    kernel/fork.c | 7 +++++--
    1 file changed, 5 insertions(+), 2 deletions(-)

    diff --git a/kernel/fork.c b/kernel/fork.c
    index 3493117c8d35..6de302e93519 100644
    --- a/kernel/fork.c
    +++ b/kernel/fork.c
    @@ -1228,13 +1228,16 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
    /* Forbid mm->exe_file change if old file still mapped. */
    old_exe_file = get_mm_exe_file(mm);
    if (old_exe_file) {
    + VMA_ITERATOR(vmi, mm, 0);
    mmap_read_lock(mm);
    - for (vma = mm->mmap; vma && !ret; vma = vma->vm_next) {
    + for_each_vma(vmi, vma) {
    if (!vma->vm_file)
    continue;
    if (path_equal(&vma->vm_file->f_path,
    - &old_exe_file->f_path))
    + &old_exe_file->f_path)) {
    ret = -EBUSY;
    + break;
    + }
    }
    mmap_read_unlock(mm);
    fput(old_exe_file);
    --
    2.30.2
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