Messages in this thread Patch in this message | | | From | Will Deacon <> | Subject | [RFC PATCH 06/21] list: Remove superfluous WRITE_ONCE() from hlist_nulls implementation | Date | Tue, 24 Mar 2020 15:36:28 +0000 |
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Commit 860c8802ace1 ("rcu: Use WRITE_ONCE() for assignments to ->pprev for hlist_nulls") added WRITE_ONCE() invocations to hlist_nulls_add_head() and hlist_nulls_del().
Since these functions should not ordinarily run concurrently with other list accessors, restore the plain C assignments so that KCSAN can yell if a data race occurs.
Cc: Eric Dumazet <edumazet@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will@kernel.org> --- include/linux/list_nulls.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h index fa51a801bf32..fd154ceb5b0d 100644 --- a/include/linux/list_nulls.h +++ b/include/linux/list_nulls.h @@ -80,10 +80,10 @@ static inline void hlist_nulls_add_head(struct hlist_nulls_node *n, struct hlist_nulls_node *first = h->first; n->next = first; - WRITE_ONCE(n->pprev, &h->first); + n->pprev = &h->first; h->first = n; if (!is_a_nulls(first)) - WRITE_ONCE(first->pprev, &n->next); + first->pprev = &n->next; } static inline void __hlist_nulls_del(struct hlist_nulls_node *n) @@ -99,7 +99,7 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n) static inline void hlist_nulls_del(struct hlist_nulls_node *n) { __hlist_nulls_del(n); - WRITE_ONCE(n->pprev, LIST_POISON2); + n->pprev = LIST_POISON2; } /** -- 2.20.1
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