fsnotify: Remove indirection from mark list addition

Adding notification mark to object list has been currently done through
fsnotify_add_{inode|vfsmount}_mark() helpers from
fsnotify_add_mark_locked() which call fsnotify_add_mark_list(). Remove
this unnecessary indirection to simplify the code.

Pushing all the locking to fsnotify_add_mark_list() also allows us to
allocate the connector structure with GFP_KERNEL mode.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 43 insertions, 23 deletions

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 8a15c64fbe80..e8c2f829ce65 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -320,12 +320,13 @@ int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
 
 static int fsnotify_attach_connector_to_object(
                                         struct fsnotify_mark_connector **connp,
+                                        spinlock_t *lock,
                                         struct inode *inode,
                                         struct vfsmount *mnt)
 {
         struct fsnotify_mark_connector *conn;
 
-        conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_ATOMIC);
+        conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL);
         if (!conn)
                 return -ENOMEM;
         INIT_HLIST_HEAD(&conn->list);
@@ -341,7 +342,12 @@ static int fsnotify_attach_connector_to_object(
          * lockless_dereference() in fsnotify().
          */
         smp_wmb();
-        *connp = conn;
+        spin_lock(lock);
+        if (!*connp)
+                *connp = conn;
+        else
+                kmem_cache_free(fsnotify_mark_connector_cachep, conn);
+        spin_unlock(lock);
 
         return 0;
 }
@@ -352,20 +358,35 @@ static int fsnotify_attach_connector_to_object(
  * to which group and for which inodes. These marks are ordered according to
  * priority, highest number first, and then by the group's location in memory.
  */
-int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
-                           struct fsnotify_mark *mark, struct inode *inode,
-                           struct vfsmount *mnt, int allow_dups)
+static int fsnotify_add_mark_list(struct fsnotify_mark *mark,
+                                  struct inode *inode, struct vfsmount *mnt,
+                                  int allow_dups)
 {
         struct fsnotify_mark *lmark, *last = NULL;
         struct fsnotify_mark_connector *conn;
+        struct fsnotify_mark_connector **connp;
+        spinlock_t *lock;
         int cmp;
-        int err;
+        int err = 0;
+
+        if (WARN_ON(!inode && !mnt))
+                return -EINVAL;
+        if (inode) {
+                connp = &inode->i_fsnotify_marks;
+                lock = &inode->i_lock;
+        } else {
+                connp = &real_mount(mnt)->mnt_fsnotify_marks;
+                lock = &mnt->mnt_root->d_lock;
+        }
 
         if (!*connp) {
-                err = fsnotify_attach_connector_to_object(connp, inode, mnt);
+                err = fsnotify_attach_connector_to_object(connp, lock,
+                                                          inode, mnt);
                 if (err)
                         return err;
         }
+        spin_lock(&mark->lock);
+        spin_lock(lock);
         conn = *connp;
 
         /* is mark the first mark? */
@@ -380,8 +401,10 @@ int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
         hlist_for_each_entry(lmark, &conn->list, obj_list) {
                 last = lmark;
 
-                if ((lmark->group == mark->group) && !allow_dups)
-                        return -EEXIST;
+                if ((lmark->group == mark->group) && !allow_dups) {
+                        err = -EEXIST;
+                        goto out_err;
+                }
 
                 cmp = fsnotify_compare_groups(lmark->group, mark->group);
                 if (cmp >= 0) {
@@ -395,7 +418,10 @@ int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
         hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
 added:
         mark->connector = conn;
-        return 0;
+out_err:
+        spin_unlock(lock);
+        spin_unlock(&mark->lock);
+        return err;
 }
 
 /*
@@ -427,22 +453,16 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
         list_add(&mark->g_list, &group->marks_list);
         atomic_inc(&group->num_marks);
         fsnotify_get_mark(mark); /* for i_list and g_list */
-
-        if (inode) {
-                ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups);
-                if (ret)
-                        goto err;
-        } else if (mnt) {
-                ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups);
-                if (ret)
-                        goto err;
-        } else {
-                BUG();
-        }
         spin_unlock(&mark->lock);
 
+        ret = fsnotify_add_mark_list(mark, inode, mnt, allow_dups);
+        if (ret)
+                goto err;
+
         if (inode)
-                __fsnotify_update_child_dentry_flags(inode);
+                fsnotify_recalc_inode_mask(inode);
+        else
+                fsnotify_recalc_vfsmount_mask(mnt);
 
         return ret;
 err: