1 files changed, 99 insertions, 65 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 6602941..5537398 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -300,12 +300,10 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 	 * Now we know that no one else is looking at the page.
 	 */
 	get_page(newpage);	/* add cache reference */
-#ifdef CONFIG_SWAP
 	if (PageSwapCache(page)) {
 		SetPageSwapCache(newpage);
 		set_page_private(newpage, page_private(page));
 	}
-#endif
 
 	radix_tree_replace_slot(pslot, newpage);
 
@@ -373,9 +371,7 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
 
 	mlock_migrate_page(newpage, page);
 
-#ifdef CONFIG_SWAP
 	ClearPageSwapCache(page);
-#endif
 	ClearPagePrivate(page);
 	set_page_private(page, 0);
 	/* page->mapping contains a flag for PageAnon() */
@@ -522,15 +518,12 @@ static int writeout(struct address_space *mapping, struct page *page)
 	remove_migration_ptes(page, page);
 
 	rc = mapping->a_ops->writepage(page, &wbc);
-	if (rc < 0)
-		/* I/O Error writing */
-		return -EIO;
 
 	if (rc != AOP_WRITEPAGE_ACTIVATE)
 		/* unlocked. Relock */
 		lock_page(page);
 
-	return -EAGAIN;
+	return (rc < 0) ? -EIO : -EAGAIN;
 }
 
 /*
@@ -841,22 +834,16 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
 	struct page_to_node *pp;
 	LIST_HEAD(pagelist);
 
+	migrate_prep();
 	down_read(&mm->mmap_sem);
 
 	/*
 	 * Build a list of pages to migrate
 	 */
-	migrate_prep();
 	for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
 		struct vm_area_struct *vma;
 		struct page *page;
 
-		/*
-		 * A valid page pointer that will not match any of the
-		 * pages that will be moved.
-		 */
-		pp->page = ZERO_PAGE(0);
-
 		err = -EFAULT;
 		vma = find_vma(mm, pp->addr);
 		if (!vma || !vma_migratable(vma))
@@ -922,41 +909,43 @@ static int do_pages_move(struct mm_struct *mm, struct task_struct *task,
 			 const int __user *nodes,
 			 int __user *status, int flags)
 {
-	struct page_to_node *pm = NULL;
+	struct page_to_node *pm;
 	nodemask_t task_nodes;
-	int err = 0;
-	int i;
+	unsigned long chunk_nr_pages;
+	unsigned long chunk_start;
+	int err;
 
 	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;
+	err = -ENOMEM;
+	pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
+	if (!pm)
 		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.
+	 * Store a chunk of page_to_node array in a page,
+	 * but keep the last one as a marker
 	 */
-	for (i = 0; i < nr_pages; i++) {
-		const void __user *p;
+	chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1;
 
-		err = -EFAULT;
-		if (get_user(p, pages + i))
-			goto out_pm;
+	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;
 
-		pm[i].addr = (unsigned long)p;
-		if (nodes) {
+		/* 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;
 
-			if (get_user(node, nodes + i))
+			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;
@@ -967,22 +956,29 @@ static int do_pages_move(struct mm_struct *mm, struct task_struct *task,
 			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;
+			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;
 
-	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))
+		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:
-	vfree(pm);
+	free_page((unsigned long)pm);
 out:
 	return err;
 }
@@ -990,25 +986,18 @@ out:
 /*
  * 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,
-			 const void __user * __user *pages,
-			 int __user *status)
+static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
+				const void __user **pages, int *status)
 {
 	unsigned long i;
-	int err;
 
 	down_read(&mm->mmap_sem);
 
 	for (i = 0; i < nr_pages; i++) {
-		const void __user *p;
-		unsigned long addr;
+		unsigned long addr = (unsigned long)(*pages);
 		struct vm_area_struct *vma;
 		struct page *page;
-
-		err = -EFAULT;
-		if (get_user(p, pages+i))
-			goto out;
-		addr = (unsigned long) p;
+		int err = -EFAULT;
 
 		vma = find_vma(mm, addr);
 		if (!vma)
@@ -1027,12 +1016,52 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
 
 		err = page_to_nid(page);
 set_status:
-		put_user(err, status+i);
+		*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:
-	up_read(&mm->mmap_sem);
 	return err;
 }
 
@@ -1045,6 +1074,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_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;
@@ -1075,12 +1105,16 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
 	 * capabilities, superuser privileges or the same
 	 * userid as the target process.
 	 */
-	if ((current->euid != task->suid) && (current->euid != task->uid) &&
-	    (current->uid != task->suid) && (current->uid != task->uid) &&
+	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)