[PATCH v2 1/4] radix-tree: propagate all tags in idr tree

[Brian Foster <bfoster@redhat.com>]

The IDR tree has hardcoded tag propagation logic to handle the
internal IDR_FREE tag and ignore all others. Fix up the hardcoded
logic to support additional tags.

This is specifically to support a new internal IDR_TGID radix tree
tag used to improve search efficiency of pids with associated
PIDTYPE_TGID tasks within a pid namespace.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 lib/radix-tree.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index b3afafe46fff..08eef33e7820 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -431,12 +431,14 @@ static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
 				tag_clear(node, IDR_FREE, 0);
 				root_tag_set(root, IDR_FREE);
 			}
-		} else {
-			/* Propagate the aggregated tag info to the new child */
-			for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
-				if (root_tag_get(root, tag))
-					tag_set(node, tag, 0);
-			}
+		}
+
+		/* Propagate the aggregated tag info to the new child */
+		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
+			if (is_idr(root) && tag == IDR_FREE)
+				continue;
+			if (root_tag_get(root, tag))
+				tag_set(node, tag, 0);
 		}
 
 		BUG_ON(shift > BITS_PER_LONG);
@@ -1368,11 +1370,13 @@ static bool __radix_tree_delete(struct radix_tree_root *root,
 	unsigned offset = get_slot_offset(node, slot);
 	int tag;
 
-	if (is_idr(root))
-		node_tag_set(root, node, IDR_FREE, offset);
-	else
-		for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
-			node_tag_clear(root, node, tag, offset);
+	for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
+		if (is_idr(root) && tag == IDR_FREE) {
+			node_tag_set(root, node, tag, offset);
+			continue;
+		}
+		node_tag_clear(root, node, tag, offset);
+	}
 
 	replace_slot(slot, NULL, node, -1, values);
 	return node && delete_node(root, node);
-- 
2.35.3