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| author | Matthew Wilcox <willy@infradead.org> | 2016-12-15 02:08:34 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-15 03:04:10 +0300 |
| commit | 91d9c05ac6c788531136888d31ef18c6a0ec160f (patch) | |
| tree | 858de508527dbe571ca87a77d572a38ebf92b55d | |
| parent | 91b9677c4c1242a3d0afd76d0e91f43808243b92 (diff) | |
| download | linux-91d9c05ac6c788531136888d31ef18c6a0ec160f.tar.xz | |
radix-tree: move rcu_head into a union with private_list
I want to be able to reference node->parent after freeing node.
Currently node->parent is in a union with rcu_head, so it is overwritten
when the node is put on the RCU list. We know that private_list is not
referenced after the node is freed, so it is safe for these two members
to share space.
Link: http://lkml.kernel.org/r/1480369871-5271-50-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/radix-tree.h | 14 | ||||
| -rw-r--r-- | lib/radix-tree.c | 1 |
2 files changed, 5 insertions, 10 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 744486057e9e..d04073ac3a9f 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -85,18 +85,12 @@ struct radix_tree_node { unsigned char offset; /* Slot offset in parent */ unsigned char count; /* Total entry count */ unsigned char exceptional; /* Exceptional entry count */ + struct radix_tree_node *parent; /* Used when ascending tree */ + void *private_data; /* For tree user */ union { - struct { - /* Used when ascending tree */ - struct radix_tree_node *parent; - /* For tree user */ - void *private_data; - }; - /* Used when freeing node */ - struct rcu_head rcu_head; + struct list_head private_list; /* For tree user */ + struct rcu_head rcu_head; /* Used when freeing node */ }; - /* For tree user */ - struct list_head private_list; void __rcu *slots[RADIX_TREE_MAP_SIZE]; unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; }; diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 60c10361cbfa..8c5911eae5e2 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -325,6 +325,7 @@ static void radix_tree_node_rcu_free(struct rcu_head *head) tag_clear(node, i, 0); node->slots[0] = NULL; + INIT_LIST_HEAD(&node->private_list); kmem_cache_free(radix_tree_node_cachep, node); } |