new helper: iterate_mounts()

apply function to vfsmounts in set returned by collect_mounts(),
stop if it returns non-zero.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 33 insertions, 34 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index d25d4602ab50..d5906c19e08e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1246,6 +1246,21 @@ void drop_collected_mounts(struct vfsmount *mnt)
         release_mounts(&umount_list);
 }
 
+int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
+                   struct vfsmount *root)
+{
+        struct vfsmount *mnt;
+        int res = f(root, arg);
+        if (res)
+                return res;
+        list_for_each_entry(mnt, &root->mnt_list, mnt_list) {
+                res = f(mnt, arg);
+                if (res)
+                        return res;
+        }
+        return 0;
+}
+
 static void cleanup_group_ids(struct vfsmount *mnt, struct vfsmount *end)
 {
         struct vfsmount *p;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d53bc17f93f..e764f247d0ab 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1794,7 +1794,8 @@ extern int may_umount(struct vfsmount *);
 extern long do_mount(char *, char *, char *, unsigned long, void *);
 extern struct vfsmount *collect_mounts(struct path *);
 extern void drop_collected_mounts(struct vfsmount *);
-
+extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
+                          struct vfsmount *);
 extern int vfs_statfs(struct dentry *, struct kstatfs *);
 
 extern int current_umask(void);
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index f09b42d9c32d..028e85663f27 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -548,6 +548,11 @@ int audit_remove_tree_rule(struct audit_krule *rule)
         return 0;
 }
 
+static int compare_root(struct vfsmount *mnt, void *arg)
+{
+        return mnt->mnt_root->d_inode == arg;
+}
+
 void audit_trim_trees(void)
 {
         struct list_head cursor;
@@ -559,7 +564,6 @@ void audit_trim_trees(void)
                 struct path path;
                 struct vfsmount *root_mnt;
                 struct node *node;
-                struct list_head list;
                 int err;
 
                 tree = container_of(cursor.next, struct audit_tree, list);
@@ -577,24 +581,16 @@ void audit_trim_trees(void)
                 if (!root_mnt)
                         goto skip_it;
 
-                list_add_tail(&list, &root_mnt->mnt_list);
                 spin_lock(&hash_lock);
                 list_for_each_entry(node, &tree->chunks, list) {
-                        struct audit_chunk *chunk = find_chunk(node);
-                        struct inode *inode = chunk->watch.inode;
-                        struct vfsmount *mnt;
+                        struct inode *inode = find_chunk(node)->watch.inode;
                         node->index |= 1U<<31;
-                        list_for_each_entry(mnt, &list, mnt_list) {
-                                if (mnt->mnt_root->d_inode == inode) {
-                                        node->index &= ~(1U<<31);
-                                        break;
-                                }
-                        }
+                        if (iterate_mounts(compare_root, inode, root_mnt))
+                                node->index &= ~(1U<<31);
                 }
                 spin_unlock(&hash_lock);
                 trim_marked(tree);
                 put_tree(tree);
-                list_del_init(&list);
                 drop_collected_mounts(root_mnt);
 skip_it:
                 mutex_lock(&audit_filter_mutex);
@@ -622,13 +618,17 @@ void audit_put_tree(struct audit_tree *tree)
         put_tree(tree);
 }
 
+static int tag_mount(struct vfsmount *mnt, void *arg)
+{
+        return tag_chunk(mnt->mnt_root->d_inode, arg);
+}
+
 /* called with audit_filter_mutex */
 int audit_add_tree_rule(struct audit_krule *rule)
 {
         struct audit_tree *seed = rule->tree, *tree;
         struct path path;
-        struct vfsmount *mnt, *p;
-        struct list_head list;
+        struct vfsmount *mnt;
         int err;
 
         list_for_each_entry(tree, &tree_list, list) {
@@ -654,16 +654,9 @@ int audit_add_tree_rule(struct audit_krule *rule)
                 err = -ENOMEM;
                 goto Err;
         }
-        list_add_tail(&list, &mnt->mnt_list);
 
         get_tree(tree);
-        list_for_each_entry(p, &list, mnt_list) {
-                err = tag_chunk(p->mnt_root->d_inode, tree);
-                if (err)
-                        break;
-        }
-
-        list_del(&list);
+        err = iterate_mounts(tag_mount, tree, mnt);
         drop_collected_mounts(mnt);
 
         if (!err) {
@@ -700,7 +693,6 @@ int audit_tag_tree(char *old, char *new)
         int failed = 0;
         struct path path1, path2;
         struct vfsmount *tagged;
-        struct list_head list;
         int err;
 
         err = kern_path(new, 0, &path2);
@@ -717,15 +709,12 @@ int audit_tag_tree(char *old, char *new)
                 return err;
         }
 
-        list_add_tail(&list, &tagged->mnt_list);
-
         mutex_lock(&audit_filter_mutex);
         list_add(&barrier, &tree_list);
         list_add(&cursor, &barrier);
 
         while (cursor.next != &tree_list) {
                 struct audit_tree *tree;
-                struct vfsmount *p;
                 int good_one = 0;
 
                 tree = container_of(cursor.next, struct audit_tree, list);
@@ -746,12 +735,7 @@ int audit_tag_tree(char *old, char *new)
                         continue;
                 }
 
-                list_for_each_entry(p, &list, mnt_list) {
-                        failed = tag_chunk(p->mnt_root->d_inode, tree);
-                        if (failed)
-                                break;
-                }
-
+                failed = iterate_mounts(tag_mount, tree, tagged);
                 if (failed) {
                         put_tree(tree);
                         mutex_lock(&audit_filter_mutex);
@@ -792,7 +776,6 @@ int audit_tag_tree(char *old, char *new)
         }
         list_del(&barrier);
         list_del(&cursor);
-        list_del(&list);
         mutex_unlock(&audit_filter_mutex);
         path_put(&path1);
         drop_collected_mounts(tagged);