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authorThomas Hellstrom <thellstrom@vmware.com>2012-11-20 12:16:47 +0000
committerDave Airlie <airlied@redhat.com>2012-11-28 18:36:05 +1000
commit384cc2f9688994dfd505011ba3b08e0a702030b0 (patch)
tree9d7f8d1f3a68d88442d35cd13a67563571147f29 /include/drm/drm_hashtab.h
parent7e8d9da32ea02f02a23f998cd2013408a4fe49bb (diff)
downloadvexpress-lsk-384cc2f9688994dfd505011ba3b08e0a702030b0.tar.gz
drm: Add a hash-tab rcu-safe API
While hashtab should now be RCU-safe, Add a drm_ht_xxx_api for consumers to use to make it obvious what locking mechanism is used. Document the way the rcu-safe interface should be used. Don't use rcu-safe list traversal in modify operations where we should use a spinlock / mutex anyway. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'include/drm/drm_hashtab.h')
-rw-r--r--include/drm/drm_hashtab.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/drm/drm_hashtab.h b/include/drm/drm_hashtab.h
index 3650d5d011e..fce2ef3fdff 100644
--- a/include/drm/drm_hashtab.h
+++ b/include/drm/drm_hashtab.h
@@ -61,5 +61,19 @@ extern int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
extern int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
extern void drm_ht_remove(struct drm_open_hash *ht);
+/*
+ * RCU-safe interface
+ *
+ * The user of this API needs to make sure that two or more instances of the
+ * hash table manipulation functions are never run simultaneously.
+ * The lookup function drm_ht_find_item_rcu may, however, run simultaneously
+ * with any of the manipulation functions as long as it's called from within
+ * an RCU read-locked section.
+ */
+#define drm_ht_insert_item_rcu drm_ht_insert_item
+#define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
+#define drm_ht_remove_key_rcu drm_ht_remove_key
+#define drm_ht_remove_item_rcu drm_ht_remove_item
+#define drm_ht_find_item_rcu drm_ht_find_item
#endif