rhashtable: Remove RCU marking from rhash_lock_head
The opaque type rhash_lock_head should not be marked with __rcu
because it can never be dereferenced. We should apply the RCU
marking when we turn it into a pointer which can be dereferenced.
This patch does exactly that. This fixes a number of sparse
warnings as well as getting rid of some unnecessary RCU checking.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index f7714d3..9f8bc06 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -84,7 +84,7 @@
struct lockdep_map dep_map;
- struct rhash_lock_head __rcu *buckets[] ____cacheline_aligned_in_smp;
+ struct rhash_lock_head *buckets[] ____cacheline_aligned_in_smp;
};
/*
@@ -261,13 +261,13 @@
void *arg);
void rhashtable_destroy(struct rhashtable *ht);
-struct rhash_lock_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash);
-struct rhash_lock_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash);
-struct rhash_lock_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,
- struct bucket_table *tbl,
- unsigned int hash);
+struct rhash_lock_head **rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash);
+struct rhash_lock_head **__rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash);
+struct rhash_lock_head **rht_bucket_nested_insert(struct rhashtable *ht,
+ struct bucket_table *tbl,
+ unsigned int hash);
#define rht_dereference(p, ht) \
rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))
@@ -284,21 +284,21 @@
#define rht_entry(tpos, pos, member) \
({ tpos = container_of(pos, typeof(*tpos), member); 1; })
-static inline struct rhash_lock_head __rcu *const *rht_bucket(
+static inline struct rhash_lock_head *const *rht_bucket(
const struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? rht_bucket_nested(tbl, hash) :
&tbl->buckets[hash];
}
-static inline struct rhash_lock_head __rcu **rht_bucket_var(
+static inline struct rhash_lock_head **rht_bucket_var(
struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? __rht_bucket_nested(tbl, hash) :
&tbl->buckets[hash];
}
-static inline struct rhash_lock_head __rcu **rht_bucket_insert(
+static inline struct rhash_lock_head **rht_bucket_insert(
struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash)
{
return unlikely(tbl->nest) ? rht_bucket_nested_insert(ht, tbl, hash) :
@@ -349,6 +349,12 @@
local_bh_enable();
}
+static inline struct rhash_head __rcu *__rht_ptr(
+ struct rhash_lock_head *const *bkt)
+{
+ return (struct rhash_head __rcu *)((unsigned long)*bkt & ~BIT(0));
+}
+
/*
* Where 'bkt' is a bucket and might be locked:
* rht_ptr() dereferences that pointer and clears the lock bit.
@@ -356,30 +362,30 @@
* access is guaranteed, such as when destroying the table.
*/
static inline struct rhash_head *rht_ptr(
- struct rhash_lock_head __rcu * const *bkt,
+ struct rhash_lock_head *const *bkt,
struct bucket_table *tbl,
unsigned int hash)
{
- const struct rhash_lock_head *p =
- rht_dereference_bucket_rcu(*bkt, tbl, hash);
-
- if ((((unsigned long)p) & ~BIT(0)) == 0)
- return RHT_NULLS_MARKER(bkt);
- return (void *)(((unsigned long)p) & ~BIT(0));
-}
-
-static inline struct rhash_head *rht_ptr_exclusive(
- struct rhash_lock_head __rcu * const *bkt)
-{
- const struct rhash_lock_head *p =
- rcu_dereference_protected(*bkt, 1);
+ struct rhash_head __rcu *p = __rht_ptr(bkt);
if (!p)
return RHT_NULLS_MARKER(bkt);
- return (void *)(((unsigned long)p) & ~BIT(0));
+
+ return rht_dereference_bucket_rcu(p, tbl, hash);
}
-static inline void rht_assign_locked(struct rhash_lock_head __rcu **bkt,
+static inline struct rhash_head *rht_ptr_exclusive(
+ struct rhash_lock_head *const *bkt)
+{
+ struct rhash_head __rcu *p = __rht_ptr(bkt);
+
+ if (!p)
+ return RHT_NULLS_MARKER(bkt);
+
+ return rcu_dereference_protected(p, 1);
+}
+
+static inline void rht_assign_locked(struct rhash_lock_head **bkt,
struct rhash_head *obj)
{
struct rhash_head __rcu **p = (struct rhash_head __rcu **)bkt;
@@ -390,7 +396,7 @@
}
static inline void rht_assign_unlock(struct bucket_table *tbl,
- struct rhash_lock_head __rcu **bkt,
+ struct rhash_lock_head **bkt,
struct rhash_head *obj)
{
struct rhash_head __rcu **p = (struct rhash_head __rcu **)bkt;
@@ -587,7 +593,7 @@
.ht = ht,
.key = key,
};
- struct rhash_lock_head __rcu * const *bkt;
+ struct rhash_lock_head *const *bkt;
struct bucket_table *tbl;
struct rhash_head *he;
unsigned int hash;
@@ -703,7 +709,7 @@
.ht = ht,
.key = key,
};
- struct rhash_lock_head __rcu **bkt;
+ struct rhash_lock_head **bkt;
struct rhash_head __rcu **pprev;
struct bucket_table *tbl;
struct rhash_head *head;
@@ -989,7 +995,7 @@
struct rhash_head *obj, const struct rhashtable_params params,
bool rhlist)
{
- struct rhash_lock_head __rcu **bkt;
+ struct rhash_lock_head **bkt;
struct rhash_head __rcu **pprev;
struct rhash_head *he;
unsigned int hash;
@@ -1141,7 +1147,7 @@
struct rhash_head *obj_old, struct rhash_head *obj_new,
const struct rhashtable_params params)
{
- struct rhash_lock_head __rcu **bkt;
+ struct rhash_lock_head **bkt;
struct rhash_head __rcu **pprev;
struct rhash_head *he;
unsigned int hash;