rhashtable: Use rcu_dereference_all and rcu_dereference_all_check

Add rcu_dereference_all and rcu_dereference_all_check so that
library code such as rhashtable can be used with any RCU variant.

As it stands rcu_dereference is used within rashtable, which
creates false-positive warnings if the user calls it from another
RCU context, such as preempt_disable().

Use the rcu_dereference_all and rcu_dereference_all_check calls
in rhashtable to suppress these warnings.

Also replace the rcu_dereference_raw calls in the list iterators
with rcu_dereference_all to uncover buggy calls.

Reported-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu
2025-09-09 17:50:56 +08:00
parent f75f66683d
commit bee8a520eb
2 changed files with 33 additions and 7 deletions

View File

@@ -272,13 +272,13 @@ struct rhash_lock_head __rcu **rht_bucket_nested_insert(
rcu_dereference_protected(p, lockdep_rht_mutex_is_held(ht))
#define rht_dereference_rcu(p, ht) \
rcu_dereference_check(p, lockdep_rht_mutex_is_held(ht))
rcu_dereference_all_check(p, lockdep_rht_mutex_is_held(ht))
#define rht_dereference_bucket(p, tbl, hash) \
rcu_dereference_protected(p, lockdep_rht_bucket_is_held(tbl, hash))
#define rht_dereference_bucket_rcu(p, tbl, hash) \
rcu_dereference_check(p, lockdep_rht_bucket_is_held(tbl, hash))
rcu_dereference_all_check(p, lockdep_rht_bucket_is_held(tbl, hash))
#define rht_entry(tpos, pos, member) \
({ tpos = container_of(pos, typeof(*tpos), member); 1; })
@@ -373,7 +373,7 @@ static inline struct rhash_head *__rht_ptr(
static inline struct rhash_head *rht_ptr_rcu(
struct rhash_lock_head __rcu *const *bkt)
{
return __rht_ptr(rcu_dereference(*bkt), bkt);
return __rht_ptr(rcu_dereference_all(*bkt), bkt);
}
static inline struct rhash_head *rht_ptr(
@@ -497,7 +497,7 @@ static inline void rht_assign_unlock(struct bucket_table *tbl,
for (({barrier(); }), \
pos = head; \
!rht_is_a_nulls(pos); \
pos = rcu_dereference_raw(pos->next))
pos = rcu_dereference_all(pos->next))
/**
* rht_for_each_rcu - iterate over rcu hash chain
@@ -513,7 +513,7 @@ static inline void rht_assign_unlock(struct bucket_table *tbl,
for (({barrier(); }), \
pos = rht_ptr_rcu(rht_bucket(tbl, hash)); \
!rht_is_a_nulls(pos); \
pos = rcu_dereference_raw(pos->next))
pos = rcu_dereference_all(pos->next))
/**
* rht_for_each_entry_rcu_from - iterated over rcu hash chain from given head
@@ -560,7 +560,7 @@ static inline void rht_assign_unlock(struct bucket_table *tbl,
* list returned by rhltable_lookup.
*/
#define rhl_for_each_rcu(pos, list) \
for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
for (pos = list; pos; pos = rcu_dereference_all(pos->next))
/**
* rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
@@ -574,7 +574,7 @@ static inline void rht_assign_unlock(struct bucket_table *tbl,
*/
#define rhl_for_each_entry_rcu(tpos, pos, list, member) \
for (pos = list; pos && rht_entry(tpos, pos, member); \
pos = rcu_dereference_raw(pos->next))
pos = rcu_dereference_all(pos->next))
static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
const void *obj)