mempolicy: reduce stack size of migrate_pages()
migrate_pages() is using >500 bytes stack. Reduce it.
mm/mempolicy.c: In function 'sys_migrate_pages':
mm/mempolicy.c:1344: warning: the frame size of 528 bytes is larger than 512 bytes
[akpm@linux-foundation.org: don't play with a might-be-NULL pointer]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8a73708..f969da5 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1275,33 +1275,42 @@
const unsigned long __user *, new_nodes)
{
const struct cred *cred = current_cred(), *tcred;
- struct mm_struct *mm;
+ struct mm_struct *mm = NULL;
struct task_struct *task;
- nodemask_t old;
- nodemask_t new;
nodemask_t task_nodes;
int err;
+ nodemask_t *old;
+ nodemask_t *new;
+ NODEMASK_SCRATCH(scratch);
- err = get_nodes(&old, old_nodes, maxnode);
- if (err)
- return err;
+ if (!scratch)
+ return -ENOMEM;
- err = get_nodes(&new, new_nodes, maxnode);
+ old = &scratch->mask1;
+ new = &scratch->mask2;
+
+ err = get_nodes(old, old_nodes, maxnode);
if (err)
- return err;
+ goto out;
+
+ err = get_nodes(new, new_nodes, maxnode);
+ if (err)
+ goto out;
/* Find the mm_struct */
read_lock(&tasklist_lock);
task = pid ? find_task_by_vpid(pid) : current;
if (!task) {
read_unlock(&tasklist_lock);
- return -ESRCH;
+ err = -ESRCH;
+ goto out;
}
mm = get_task_mm(task);
read_unlock(&tasklist_lock);
+ err = -EINVAL;
if (!mm)
- return -EINVAL;
+ goto out;
/*
* Check if this process has the right to modify the specified
@@ -1322,12 +1331,12 @@
task_nodes = cpuset_mems_allowed(task);
/* Is the user allowed to access the target nodes? */
- if (!nodes_subset(new, task_nodes) && !capable(CAP_SYS_NICE)) {
+ if (!nodes_subset(*new, task_nodes) && !capable(CAP_SYS_NICE)) {
err = -EPERM;
goto out;
}
- if (!nodes_subset(new, node_states[N_HIGH_MEMORY])) {
+ if (!nodes_subset(*new, node_states[N_HIGH_MEMORY])) {
err = -EINVAL;
goto out;
}
@@ -1336,10 +1345,13 @@
if (err)
goto out;
- err = do_migrate_pages(mm, &old, &new,
+ err = do_migrate_pages(mm, old, new,
capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE);
out:
- mmput(mm);
+ if (mm)
+ mmput(mm);
+ NODEMASK_SCRATCH_FREE(scratch);
+
return err;
}