[PATCH bpf-next v1 04/11] namei: expose the stepwise ancestor walk to fs/

[Justin Suess <utilityemal77@gmail.com>]

Make vfs_walk_start(), vfs_walk_next() and vfs_walk_end() non-static
and declare them in fs/internal.h next to the walk state, so an
iterating consumer (BPF) can drive the walk with every step and
invariant staying in namei.c.  vfs_walk_ancestors() and its callback
contract are unchanged.

Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
 fs/internal.h | 5 +++++
 fs/namei.c    | 8 ++++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index bfe62c9bdfc9..3ce2220ff57f 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -81,6 +81,11 @@ struct vfs_ancestor_walk {
 	unsigned int flags;	/* VFS_WALK_* */
 };
 
+void vfs_walk_start(struct vfs_ancestor_walk *aw, const struct path *path,
+		    unsigned int flags);
+int vfs_walk_next(struct vfs_ancestor_walk *aw);
+void vfs_walk_end(struct vfs_ancestor_walk *aw);
+
 void __init filename_init(void);
 
 /*
diff --git a/fs/namei.c b/fs/namei.c
index 6d5b4b214334..d6151fa27844 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2249,8 +2249,8 @@ static const struct path vfs_walk_no_root;
  * @path: position to walk up from; never modified
  * @flags: %VFS_WALK_* flags; none defined yet, pass 0
  */
-static void vfs_walk_start(struct vfs_ancestor_walk *aw,
-			   const struct path *path, unsigned int flags)
+void vfs_walk_start(struct vfs_ancestor_walk *aw, const struct path *path,
+		    unsigned int flags)
 {
 	if (WARN_ON_ONCE(flags))
 		flags = 0;
@@ -2299,7 +2299,7 @@ static int vfs_walk_step_ref(struct vfs_ancestor_walk *aw)
  * Returns: 0 with @aw->pos valid, 1 once the walk has passed the real
  * root.
  */
-static int vfs_walk_next(struct vfs_ancestor_walk *aw)
+int vfs_walk_next(struct vfs_ancestor_walk *aw)
 {
 	if (aw->flags & VFS_WALK_STARTED) {
 		int err = vfs_walk_step_ref(aw);
@@ -2317,7 +2317,7 @@ static int vfs_walk_next(struct vfs_ancestor_walk *aw)
  * vfs_walk_end - finish a stepwise ancestor walk
  * @aw: the walk; its positions, including @aw->pos, become invalid
  */
-static void vfs_walk_end(struct vfs_ancestor_walk *aw)
+void vfs_walk_end(struct vfs_ancestor_walk *aw)
 {
 	path_put(&aw->pos);
 }
-- 
2.55.0