diff options
Diffstat (limited to 'include/linux/radix-tree.h')
| -rw-r--r-- | include/linux/radix-tree.h | 36 |
1 files changed, 19 insertions, 17 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 634b8e674ac5..9f38fe50217e 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -36,17 +36,6 @@ * RCU. */ #define RADIX_TREE_INDIRECT_PTR 1 -#define RADIX_TREE_RETRY ((void *)-1UL) - -static inline void *radix_tree_ptr_to_indirect(void *ptr) -{ - return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR); -} - -static inline void *radix_tree_indirect_to_ptr(void *ptr) -{ - return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR); -} static inline int radix_tree_is_indirect_ptr(void *ptr) { @@ -138,16 +127,29 @@ do { \ * removed. * * For use with radix_tree_lookup_slot(). Caller must hold tree at least read - * locked across slot lookup and dereference. More likely, will be used with - * radix_tree_replace_slot(), as well, so caller will hold tree write locked. + * locked across slot lookup and dereference. Not required if write lock is + * held (ie. items cannot be concurrently inserted). + * + * radix_tree_deref_retry must be used to confirm validity of the pointer if + * only the read lock is held. */ static inline void *radix_tree_deref_slot(void **pslot) { - void *ret = rcu_dereference(*pslot); - if (unlikely(radix_tree_is_indirect_ptr(ret))) - ret = RADIX_TREE_RETRY; - return ret; + return rcu_dereference(*pslot); } + +/** + * radix_tree_deref_retry - check radix_tree_deref_slot + * @arg: pointer returned by radix_tree_deref_slot + * Returns: 0 if retry is not required, otherwise retry is required + * + * radix_tree_deref_retry must be used with radix_tree_deref_slot. + */ +static inline int radix_tree_deref_retry(void *arg) +{ + return unlikely((unsigned long)arg & RADIX_TREE_INDIRECT_PTR); +} + /** * radix_tree_replace_slot - replace item in a slot * @pslot: pointer to slot, returned by radix_tree_lookup_slot |