From ba6306e3f648a857ae52ddcabc2859542fd2f94c Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 16 May 2019 15:19:46 +0800 Subject: 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 Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 58 +++++++++++++++++++++++++--------------------- 1 file changed, 32 insertions(+), 26 deletions(-) (limited to 'include/linux/rhashtable.h') diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index f7714d3b46bd..9f8bc06d4136 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -84,7 +84,7 @@ struct bucket_table { 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 rhashtable_free_and_destroy(struct rhashtable *ht, 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 @@ struct rhash_lock_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, #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 @@ static inline void rht_unlock(struct bucket_table *tbl, 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 @@ static inline void rht_unlock(struct bucket_table *tbl, * 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); + struct rhash_head __rcu *p = __rht_ptr(bkt); - if ((((unsigned long)p) & ~BIT(0)) == 0) + if (!p) return RHT_NULLS_MARKER(bkt); - return (void *)(((unsigned long)p) & ~BIT(0)); + + return rht_dereference_bucket_rcu(p, tbl, hash); } static inline struct rhash_head *rht_ptr_exclusive( - struct rhash_lock_head __rcu * const *bkt) + struct rhash_lock_head *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 rcu_dereference_protected(p, 1); } -static inline void rht_assign_locked(struct rhash_lock_head __rcu **bkt, +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_locked(struct rhash_lock_head __rcu **bkt, } 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 @@ static inline struct rhash_head *__rhashtable_lookup( .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 @@ static inline void *__rhashtable_insert_fast( .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 @@ static inline int __rhashtable_remove_fast_one( 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 @@ static inline int __rhashtable_replace_fast( 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; -- cgit v1.2.3-59-g8ed1b