mm: extract do_pages_move() out of sys_move_pages()

To prepare the chunking, move the sys_move_pages() code that is used when
nodes!=NULL into do_pages_move().  And rename do_move_pages() into
do_move_page_to_node_array().

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 86 insertions, 66 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index a4c29081ebce..11c6c56ec017 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -826,9 +826,11 @@ static struct page *new_page_node(struct page *p, unsigned long private,
  * 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_pages(struct mm_struct *mm, struct page_to_node *pm,
-                                int migrate_all)
+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;
@@ -906,6 +908,81 @@ set_status:
 }
 
 /*
+ * 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 = NULL;
+        nodemask_t task_nodes;
+        int err = 0;
+        int i;
+
+        task_nodes = cpuset_mems_allowed(task);
+
+        /* Limit nr_pages so that the multiplication may not overflow */
+        if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
+                err = -E2BIG;
+                goto out;
+        }
+
+        pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
+        if (!pm) {
+                err = -ENOMEM;
+                goto out;
+        }
+
+        /*
+         * Get parameters from user space and initialize the pm
+         * array. Return various errors if the user did something wrong.
+         */
+        for (i = 0; i < nr_pages; i++) {
+                const void __user *p;
+
+                err = -EFAULT;
+                if (get_user(p, pages + i))
+                        goto out_pm;
+
+                pm[i].addr = (unsigned long)p;
+                if (nodes) {
+                        int node;
+
+                        if (get_user(node, nodes + i))
+                                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[i].node = node;
+                } else
+                        pm[i].node = 0; /* anything to not match MAX_NUMNODES */
+        }
+        /* End marker */
+        pm[nr_pages].node = MAX_NUMNODES;
+
+        err = do_move_page_to_node_array(mm, pm, flags & MPOL_MF_MOVE_ALL);
+        if (err >= 0)
+                /* Return status information */
+                for (i = 0; i < nr_pages; i++)
+                        if (put_user(pm[i].status, status + i))
+                                err = -EFAULT;
+
+out_pm:
+        vfree(pm);
+out:
+        return err;
+}
+
+/*
  * Determine the nodes of an array of pages and store it in an array of status.
  */
 static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
@@ -963,12 +1040,9 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
                         const int __user *nodes,
                         int __user *status, int flags)
 {
-        int err = 0;
-        int i;
         struct task_struct *task;
-        nodemask_t task_nodes;
         struct mm_struct *mm;
-        struct page_to_node *pm = NULL;
+        int err;
 
         /* Check flags */
         if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
@@ -1000,75 +1074,21 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
             (current->uid != task->suid) && (current->uid != task->uid) &&
             !capable(CAP_SYS_NICE)) {
                 err = -EPERM;
-                goto out2;
+                goto out;
         }
 
         err = security_task_movememory(task);
         if (err)
-                goto out2;
+                goto out;
 
-        if (!nodes) {
+        if (nodes) {
+                err = do_pages_move(mm, task, nr_pages, pages, nodes, status,
+                                    flags);
+        } else {
                 err = do_pages_stat(mm, nr_pages, pages, status);
-                goto out2;
-        }
-
-        task_nodes = cpuset_mems_allowed(task);
-
-        /* Limit nr_pages so that the multiplication may not overflow */
-        if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
-                err = -E2BIG;
-                goto out2;
         }
 
-        pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
-        if (!pm) {
-                err = -ENOMEM;
-                goto out2;
-        }
-
-        /*
-         * Get parameters from user space and initialize the pm
-         * array. Return various errors if the user did something wrong.
-         */
-        for (i = 0; i < nr_pages; i++) {
-                const void __user *p;
-
-                err = -EFAULT;
-                if (get_user(p, pages + i))
-                        goto out;
-
-                pm[i].addr = (unsigned long)p;
-                if (nodes) {
-                        int node;
-
-                        if (get_user(node, nodes + i))
-                                goto out;
-
-                        err = -ENODEV;
-                        if (!node_state(node, N_HIGH_MEMORY))
-                                goto out;
-
-                        err = -EACCES;
-                        if (!node_isset(node, task_nodes))
-                                goto out;
-
-                        pm[i].node = node;
-                } else
-                        pm[i].node = 0; /* anything to not match MAX_NUMNODES */
-        }
-        /* End marker */
-        pm[nr_pages].node = MAX_NUMNODES;
-
-        err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
-        if (err >= 0)
-                /* Return status information */
-                for (i = 0; i < nr_pages; i++)
-                        if (put_user(pm[i].status, status + i))
-                                err = -EFAULT;
-
 out:
-        vfree(pm);
-out2:
         mmput(mm);
         return err;
 }