+#ifdef CONFIG_NUMA
+/*
+ * Move a list of individual pages
+ */
+struct page_to_node {
+ unsigned long addr;
+ struct page *page;
+ int node;
+ int status;
+};
+
+static struct page *new_page_node(struct page *p, unsigned long private,
+ int **result)
+{
+ struct page_to_node *pm = (struct page_to_node *)private;
+
+ while (pm->node != MAX_NUMNODES && pm->page != p)
+ pm++;
+
+ if (pm->node == MAX_NUMNODES)
+ return NULL;
+
+ *result = &pm->status;
+
+ return alloc_pages_exact_node(pm->node,
+ GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0);
+}
+
+/*
+ * Move a set of pages as indicated in the pm array. The addr
+ * field must be set to the virtual address of the page to be moved
+ * and the node number must contain a valid target node.
+ * The pm array ends with node = MAX_NUMNODES.
+ */
+static int do_move_page_to_node_array(struct mm_struct *mm,
+ struct page_to_node *pm,
+ int migrate_all)
+{
+ int err;
+ struct page_to_node *pp;
+ LIST_HEAD(pagelist);
+
+ down_read(&mm->mmap_sem);
+
+ /*
+ * Build a list of pages to migrate
+ */
+ for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
+ struct vm_area_struct *vma;
+ struct page *page;
+
+ err = -EFAULT;
+ vma = find_vma(mm, pp->addr);
+ if (!vma || !vma_migratable(vma))
+ goto set_status;
+
+ page = follow_page(vma, pp->addr, FOLL_GET);
+
+ err = PTR_ERR(page);
+ if (IS_ERR(page))
+ goto set_status;
+
+ err = -ENOENT;
+ if (!page)
+ goto set_status;
+
+ if (PageReserved(page)) /* Check for zero page */
+ goto put_and_set;
+
+ pp->page = page;
+ err = page_to_nid(page);
+
+ if (err == pp->node)
+ /*
+ * Node already in the right place
+ */
+ goto put_and_set;
+
+ err = -EACCES;
+ if (page_mapcount(page) > 1 &&
+ !migrate_all)
+ goto put_and_set;
+
+ err = isolate_lru_page(page);
+ if (!err)
+ list_add_tail(&page->lru, &pagelist);
+put_and_set:
+ /*
+ * Either remove the duplicate refcount from
+ * isolate_lru_page() or drop the page ref if it was
+ * not isolated.
+ */
+ put_page(page);
+set_status:
+ pp->status = err;
+ }
+
+ err = 0;
+ if (!list_empty(&pagelist))
+ err = migrate_pages(&pagelist, new_page_node,
+ (unsigned long)pm);
+
+ up_read(&mm->mmap_sem);
+ return err;
+}
+
+/*
+ * Migrate an array of page address onto an array of nodes and fill
+ * the corresponding array of status.
+ */
+static int do_pages_move(struct mm_struct *mm, struct task_struct *task,
+ unsigned long nr_pages,
+ const void __user * __user *pages,
+ const int __user *nodes,
+ int __user *status, int flags)
+{
+ struct page_to_node *pm;
+ nodemask_t task_nodes;
+ unsigned long chunk_nr_pages;
+ unsigned long chunk_start;
+ int err;
+
+ task_nodes = cpuset_mems_allowed(task);
+
+ err = -ENOMEM;
+ pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
+ if (!pm)
+ goto out;
+
+ migrate_prep();
+
+ /*
+ * Store a chunk of page_to_node array in a page,
+ * but keep the last one as a marker
+ */
+ chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1;
+
+ for (chunk_start = 0;
+ chunk_start < nr_pages;
+ chunk_start += chunk_nr_pages) {
+ int j;
+
+ if (chunk_start + chunk_nr_pages > nr_pages)
+ chunk_nr_pages = nr_pages - chunk_start;
+
+ /* fill the chunk pm with addrs and nodes from user-space */
+ for (j = 0; j < chunk_nr_pages; j++) {
+ const void __user *p;
+ int node;
+
+ err = -EFAULT;
+ if (get_user(p, pages + j + chunk_start))
+ goto out_pm;
+ pm[j].addr = (unsigned long) p;
+
+ if (get_user(node, nodes + j + chunk_start))
+ goto out_pm;
+
+ err = -ENODEV;
+ if (!node_state(node, N_HIGH_MEMORY))
+ goto out_pm;
+
+ err = -EACCES;
+ if (!node_isset(node, task_nodes))
+ goto out_pm;
+
+ pm[j].node = node;
+ }
+
+ /* End marker for this chunk */
+ pm[chunk_nr_pages].node = MAX_NUMNODES;
+
+ /* Migrate this chunk */
+ err = do_move_page_to_node_array(mm, pm,
+ flags & MPOL_MF_MOVE_ALL);
+ if (err < 0)
+ goto out_pm;
+
+ /* Return status information */
+ for (j = 0; j < chunk_nr_pages; j++)
+ if (put_user(pm[j].status, status + j + chunk_start)) {
+ err = -EFAULT;
+ goto out_pm;
+ }
+ }
+ err = 0;
+
+out_pm:
+ free_page((unsigned long)pm);
+out:
+ return err;
+}
+
+/*
+ * Determine the nodes of an array of pages and store it in an array of status.
+ */
+static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
+ const void __user **pages, int *status)
+{
+ unsigned long i;
+
+ down_read(&mm->mmap_sem);
+
+ for (i = 0; i < nr_pages; i++) {
+ unsigned long addr = (unsigned long)(*pages);
+ struct vm_area_struct *vma;
+ struct page *page;
+ int err = -EFAULT;
+
+ vma = find_vma(mm, addr);
+ if (!vma)
+ goto set_status;
+
+ page = follow_page(vma, addr, 0);
+
+ err = PTR_ERR(page);
+ if (IS_ERR(page))
+ goto set_status;
+
+ err = -ENOENT;
+ /* Use PageReserved to check for zero page */
+ if (!page || PageReserved(page))
+ goto set_status;
+
+ err = page_to_nid(page);
+set_status:
+ *status = err;
+
+ pages++;
+ status++;
+ }
+
+ up_read(&mm->mmap_sem);
+}
+
+/*
+ * Determine the nodes of a user array of pages and store it in
+ * a user array of status.
+ */
+static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
+ const void __user * __user *pages,
+ int __user *status)
+{
+#define DO_PAGES_STAT_CHUNK_NR 16
+ const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR];
+ int chunk_status[DO_PAGES_STAT_CHUNK_NR];
+ unsigned long i, chunk_nr = DO_PAGES_STAT_CHUNK_NR;
+ int err;
+
+ for (i = 0; i < nr_pages; i += chunk_nr) {
+ if (chunk_nr + i > nr_pages)
+ chunk_nr = nr_pages - i;
+
+ err = copy_from_user(chunk_pages, &pages[i],
+ chunk_nr * sizeof(*chunk_pages));
+ if (err) {
+ err = -EFAULT;
+ goto out;
+ }
+
+ do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
+
+ err = copy_to_user(&status[i], chunk_status,
+ chunk_nr * sizeof(*chunk_status));
+ if (err) {
+ err = -EFAULT;
+ goto out;
+ }
+ }
+ err = 0;
+
+out:
+ return err;
+}
+
+/*
+ * Move a list of pages in the address space of the currently executing
+ * process.
+ */
+SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
+ const void __user * __user *, pages,
+ const int __user *, nodes,
+ int __user *, status, int, flags)
+{
+ const struct cred *cred = current_cred(), *tcred;
+ struct task_struct *task;
+ struct mm_struct *mm;
+ int err;
+
+ /* Check flags */
+ if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
+ return -EINVAL;
+
+ if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
+ return -EPERM;
+
+ /* Find the mm_struct */
+ read_lock(&tasklist_lock);
+ task = pid ? find_task_by_vpid(pid) : current;
+ if (!task) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+ mm = get_task_mm(task);
+ read_unlock(&tasklist_lock);
+
+ if (!mm)
+ return -EINVAL;
+
+ /*
+ * Check if this process has the right to modify the specified
+ * process. The right exists if the process has administrative
+ * capabilities, superuser privileges or the same
+ * userid as the target process.
+ */
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
+ cred->uid != tcred->suid && cred->uid != tcred->uid &&
+ !capable(CAP_SYS_NICE)) {
+ rcu_read_unlock();
+ err = -EPERM;
+ goto out;
+ }
+ rcu_read_unlock();
+
+ err = security_task_movememory(task);
+ if (err)
+ goto out;
+
+ if (nodes) {
+ err = do_pages_move(mm, task, nr_pages, pages, nodes, status,
+ flags);
+ } else {
+ err = do_pages_stat(mm, nr_pages, pages, status);
+ }
+
+out:
+ mmput(mm);
+ return err;
+}
+
+/*
+ * Call migration functions in the vma_ops that may prepare
+ * memory in a vm for migration. migration functions may perform
+ * the migration for vmas that do not have an underlying page struct.
+ */
+int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
+ const nodemask_t *from, unsigned long flags)
+{
+ struct vm_area_struct *vma;
+ int err = 0;
+
+ for (vma = mm->mmap; vma && !err; vma = vma->vm_next) {
+ if (vma->vm_ops && vma->vm_ops->migrate) {
+ err = vma->vm_ops->migrate(vma, to, from, flags);
+ if (err)
+ break;
+ }
+ }
+ return err;
+}
+#endif