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authorNeilBrown <neilb@suse.com>2018-06-18 12:52:50 +1000
committerDavid S. Miller <davem@davemloft.net>2018-06-22 13:43:28 +0900
commitc0690016a73fe6bd456887bbbe6e10c7f0096554 (patch)
tree7b835ab9e83decb0f9be1f616daa5374dd47559d /include/linux/rhashtable.h
parent0ad66449aa3cbaedbdeaf55bffce74084bb7e9f9 (diff)
rhashtable: clean up dereference of ->future_tbl.
Using rht_dereference_bucket() to dereference ->future_tbl looks like a type error, and could be confusing. Using rht_dereference_rcu() to test a pointer for NULL adds an unnecessary barrier - rcu_access_pointer() is preferred for NULL tests when no lock is held. This uses 3 different ways to access ->future_tbl. - if we know the mutex is held, use rht_dereference() - if we don't hold the mutex, and are only testing for NULL, use rcu_access_pointer() - otherwise (using RCU protection for true dereference), use rht_dereference_rcu(). Note that this includes a simplification of the call to rhashtable_last_table() - we don't do an extra dereference before the call any more. Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/rhashtable.h')
-rw-r--r--include/linux/rhashtable.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 3f3a182bd0b4..eb7111039247 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -595,7 +595,7 @@ static inline void *__rhashtable_insert_fast(
lock = rht_bucket_lock(tbl, hash);
spin_lock_bh(lock);
- if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+ if (unlikely(rcu_access_pointer(tbl->future_tbl))) {
slow_path:
spin_unlock_bh(lock);
rcu_read_unlock();