diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/idr.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index 762c3f2c631d..fa035f96f2a3 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -79,6 +79,22 @@ struct idr { #define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC) +/** + * idr synchronization (stolen from radix-tree.h) + * + * idr_find() is able to be called locklessly, using RCU. The caller must + * ensure calls to this function are made within rcu_read_lock() regions. + * Other readers (lock-free or otherwise) and modifications may be running + * concurrently. + * + * It is still required that the caller manage the synchronization and + * lifetimes of the items. So if RCU lock-free lookups are used, typically + * this would mean that the items have their own locks, or are amenable to + * lock-free access; and that the items are freed by RCU (or only freed after + * having been deleted from the idr tree *and* a synchronize_rcu() grace + * period). + */ + /* * This is what we export. */ |