From 3e252fa7d4f711798e7a3f5ff2d7b62f0e2987ce Mon Sep 17 00:00:00 2001 From: Ross Zwisler Date: Fri, 18 May 2018 16:08:58 -0700 Subject: [PATCH] radix tree test suite: add item_delete_rcu() Currently the lifetime of "struct item" entries in the radix tree are not controlled by RCU, but are instead deleted inline as they are removed from the tree. In the following patches we add a test which has threads iterating over items pulled from the tree and verifying them in an rcu_read_lock()/rcu_read_unlock() section. This means that though an item has been removed from the tree it could still be being worked on by other threads until the RCU grace period expires. So, we need to actually free the "struct item" structures at the end of the grace period, just as we do with "struct radix_tree_node" items. Link: http://lkml.kernel.org/r/20180503192430.7582-4-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler Cc: Christoph Hellwig Cc: CR, Sapthagirish Cc: Dan Williams Cc: Dave Chinner Cc: Jan Kara Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- tools/testing/radix-tree/test.c | 19 +++++++++++++++++++ tools/testing/radix-tree/test.h | 2 ++ 2 files changed, 21 insertions(+) diff --git a/tools/testing/radix-tree/test.c b/tools/testing/radix-tree/test.c index 5978ab1f403d..def6015570b2 100644 --- a/tools/testing/radix-tree/test.c +++ b/tools/testing/radix-tree/test.c @@ -75,6 +75,25 @@ int item_delete(struct radix_tree_root *root, unsigned long index) return 0; } +static void item_free_rcu(struct rcu_head *head) +{ + struct item *item = container_of(head, struct item, rcu_head); + + free(item); +} + +int item_delete_rcu(struct radix_tree_root *root, unsigned long index) +{ + struct item *item = radix_tree_delete(root, index); + + if (item) { + item_sanity(item, index); + call_rcu(&item->rcu_head, item_free_rcu); + return 1; + } + return 0; +} + void item_check_present(struct radix_tree_root *root, unsigned long index) { struct item *item; diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h index d9c031dbeb1a..8cf4a7a7f94c 100644 --- a/tools/testing/radix-tree/test.h +++ b/tools/testing/radix-tree/test.h @@ -5,6 +5,7 @@ #include struct item { + struct rcu_head rcu_head; unsigned long index; unsigned int order; }; @@ -15,6 +16,7 @@ int item_insert(struct radix_tree_root *root, unsigned long index); int item_insert_order(struct radix_tree_root *root, unsigned long index, unsigned order); int item_delete(struct radix_tree_root *root, unsigned long index); +int item_delete_rcu(struct radix_tree_root *root, unsigned long index); struct item *item_lookup(struct radix_tree_root *root, unsigned long index); void item_check_present(struct radix_tree_root *root, unsigned long index);