[PATCH] page migration: Fail with error if swap not setup

[linux-2.6-omap-h63xx.git] / mm / mempolicy.c

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 954981b14303f2298a19646c770984aebac0a812..b21869a39f0b0380265fb3bd9e0ed885a29afa0d 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -330,9 +330,19 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
        int err;
        struct vm_area_struct *first, *vma, *prev;
 
-       /* Clear the LRU lists so pages can be isolated */
-       if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+       if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
+               /* Must have swap device for migration */
+               if (nr_swap_pages <= 0)
+                       return ERR_PTR(-ENODEV);
+
+               /*
+                * Clear the LRU lists so pages can be isolated.
+                * Note that pages may be moved off the LRU after we have
+                * drained them. Those pages will fail to migrate like other
+                * pages that may be busy.
+                */
                lru_add_drain_all();
+       }
 
        first = find_vma(mm, start);
        if (!first)
@@ -748,7 +758,7 @@ long do_mbind(unsigned long start, unsigned long len,
                                      MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
            || mode > MPOL_MAX)
                return -EINVAL;
-       if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_RESOURCE))
+       if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
                return -EPERM;
 
        if (start & ~PAGE_MASK)
@@ -942,20 +952,20 @@ asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
         */
        if ((current->euid != task->suid) && (current->euid != task->uid) &&
            (current->uid != task->suid) && (current->uid != task->uid) &&
-           !capable(CAP_SYS_ADMIN)) {
+           !capable(CAP_SYS_NICE)) {
                err = -EPERM;
                goto out;
        }
 
        task_nodes = cpuset_mems_allowed(task);
        /* Is the user allowed to access the target nodes? */
-       if (!nodes_subset(new, task_nodes) && !capable(CAP_SYS_ADMIN)) {
+       if (!nodes_subset(new, task_nodes) && !capable(CAP_SYS_NICE)) {
                err = -EPERM;
                goto out;
        }
 
        err = do_migrate_pages(mm, &old, &new,
-               capable(CAP_SYS_ADMIN) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
+               capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
 out:
        mmput(mm);
        return err;