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    Subject[PATCH 1/4] mempolicy: introduce __get_vma_policy(), export get_task_policy()
    Extract the code which looks for vma's policy from get_vma_policy()
    into the new helper, __get_vma_policy(). Export get_task_policy().

    Signed-off-by: Oleg Nesterov <oleg@redhat.com>
    ---
    include/linux/mempolicy.h | 3 +++
    mm/mempolicy.c | 44 ++++++++++++++++++++++++++------------------
    2 files changed, 29 insertions(+), 18 deletions(-)

    diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
    index 5e4bfce..e1abe24 100644
    --- a/include/linux/mempolicy.h
    +++ b/include/linux/mempolicy.h
    @@ -134,6 +134,9 @@ void mpol_free_shared_policy(struct shared_policy *p);
    struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp,
    unsigned long idx);

    +struct mempolicy *get_task_policy(struct task_struct *p);
    +struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
    + unsigned long addr);
    struct mempolicy *get_vma_policy(struct task_struct *tsk,
    struct vm_area_struct *vma, unsigned long addr);
    bool vma_policy_mof(struct vm_area_struct *vma);
    diff --git a/mm/mempolicy.c b/mm/mempolicy.c
    index ad27bbc..4378c33 100644
    --- a/mm/mempolicy.c
    +++ b/mm/mempolicy.c
    @@ -123,7 +123,7 @@ static struct mempolicy default_policy = {

    static struct mempolicy preferred_node_policy[MAX_NUMNODES];

    -static struct mempolicy *get_task_policy(struct task_struct *p)
    +struct mempolicy *get_task_policy(struct task_struct *p)
    {
    struct mempolicy *pol = p->mempolicy;
    int node;
    @@ -1603,23 +1603,8 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,

    #endif

    -/*
    - * get_vma_policy(@task, @vma, @addr)
    - * @task: task for fallback if vma policy == default
    - * @vma: virtual memory area whose policy is sought
    - * @addr: address in @vma for shared policy lookup
    - *
    - * Returns effective policy for a VMA at specified address.
    - * Falls back to @task or system default policy, as necessary.
    - * Current or other task's task mempolicy and non-shared vma policies must be
    - * protected by task_lock(task) by the caller.
    - * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
    - * count--added by the get_policy() vm_op, as appropriate--to protect against
    - * freeing by another task. It is the caller's responsibility to free the
    - * extra reference for shared policies.
    - */
    -struct mempolicy *get_vma_policy(struct task_struct *task,
    - struct vm_area_struct *vma, unsigned long addr)
    +struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
    + unsigned long addr)
    {
    struct mempolicy *pol = NULL;

    @@ -1640,6 +1625,29 @@ struct mempolicy *get_vma_policy(struct task_struct *task,
    }
    }

    + return pol;
    +}
    +
    +/*
    + * get_vma_policy(@task, @vma, @addr)
    + * @task: task for fallback if vma policy == default
    + * @vma: virtual memory area whose policy is sought
    + * @addr: address in @vma for shared policy lookup
    + *
    + * Returns effective policy for a VMA at specified address.
    + * Falls back to @task or system default policy, as necessary.
    + * Current or other task's task mempolicy and non-shared vma policies must be
    + * protected by task_lock(task) by the caller.
    + * Shared policies [those marked as MPOL_F_SHARED] require an extra reference
    + * count--added by the get_policy() vm_op, as appropriate--to protect against
    + * freeing by another task. It is the caller's responsibility to free the
    + * extra reference for shared policies.
    + */
    +struct mempolicy *get_vma_policy(struct task_struct *task,
    + struct vm_area_struct *vma, unsigned long addr)
    +{
    + struct mempolicy *pol = __get_vma_policy(vma, addr);
    +
    if (!pol)
    pol = get_task_policy(task);

    --
    1.5.5.1



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