list.h: new helper - hlist_add_fake()

Make node look as if it was on hlist, with hlist_del()
working correctly.  Usable without any locking...

Convert a couple of places where we want to do that to
inode->i_hash.

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

3 files changed, 8 insertions, 2 deletions

diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 78449280dae0..8afd7e84f98d 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -211,7 +211,7 @@ static struct dentry *hfsplus_file_lookup(struct inode *dir, struct dentry *dent
          * appear hashed, but do not put on any lists.  hlist_del()
          * will work fine and require no locking.
          */
-        inode->i_hash.pprev = &inode->i_hash.next;
+        hlist_add_fake(&inode->i_hash);
 
         mark_inode_dirty(inode);
 out:
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index f8332dc8eeb2..3a09423b6c22 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -497,7 +497,7 @@ struct inode *diReadSpecial(struct super_block *sb, ino_t inum, int secondary)
          * appear hashed, but do not put on any lists.  hlist_del()
          * will work fine and require no locking.
          */
-        ip->i_hash.pprev = &ip->i_hash.next;
+        hlist_add_fake(&ip->i_hash);
 
         return (ip);
 }
diff --git a/include/linux/list.h b/include/linux/list.h
index 88a000617d77..9a5f8a71810c 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -636,6 +636,12 @@ static inline void hlist_add_after(struct hlist_node *n,
                 next->next->pprev  = &next->next;
 }
 
+/* after that we'll appear to be on some hlist and hlist_del will work */
+static inline void hlist_add_fake(struct hlist_node *n)
+{
+        n->pprev = &n->next;
+}
+
 /*
  * Move a list from one list head to another. Fixup the pprev
  * reference of the first entry if it exists.