From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxx Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: CR, Sapthagirish <sapthagirish.cr@xxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/radix-tree/test.c | 19 +++++++++++++++++++ tools/testing/radix-tree/test.h | 2 ++ 2 files changed, 21 insertions(+) diff -puN tools/testing/radix-tree/test.c~radix-tree-test-suite-add-item_delete_rcu tools/testing/radix-tree/test.c --- a/tools/testing/radix-tree/test.c~radix-tree-test-suite-add-item_delete_rcu +++ a/tools/testing/radix-tree/test.c @@ -75,6 +75,25 @@ int item_delete(struct radix_tree_root * 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 -puN tools/testing/radix-tree/test.h~radix-tree-test-suite-add-item_delete_rcu tools/testing/radix-tree/test.h --- a/tools/testing/radix-tree/test.h~radix-tree-test-suite-add-item_delete_rcu +++ a/tools/testing/radix-tree/test.h @@ -5,6 +5,7 @@ #include <linux/rcupdate.h> struct item { + struct rcu_head rcu_head; unsigned long index; unsigned int order; }; @@ -15,6 +16,7 @@ int item_insert(struct radix_tree_root * 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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
