* [PATCH] rcu: Add necessary WRITE_ONCE()
@ 2023-06-19 9:46 Alan Huang
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From: Alan Huang @ 2023-06-19 9:46 UTC (permalink / raw)
To: paulmck; +Cc: rcu, linux-kernel, Alan Huang
Commit c54a2744497d("list: Add hlist_unhashed_lockless()") and
commit 860c8802ace1("rcu: Use WRITE_ONCE() for assignments to
->pprev for hlist_nulls") added various WRITE_ONCE() to pair with
the READ_ONCE() in hlist_unhashed_lockless(), but there are still
some places where WRITE_ONCE() was not added, this commit adds that.
Also add WRITE_ONCE() to pair with the READ_ONCE() in hlist_empty().
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
---
include/linux/list.h | 6 +++---
include/linux/list_nulls.h | 2 +-
include/linux/rculist_nulls.h | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index ac366958ea..ef2d895d3c 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -912,7 +912,7 @@ static inline void hlist_del(struct hlist_node *n)
{
__hlist_del(n);
n->next = LIST_POISON1;
- n->pprev = LIST_POISON2;
+ WRITE_ONCE(n->pprev, LIST_POISON2);
}
/**
@@ -1026,8 +1026,8 @@ static inline void hlist_move_list(struct hlist_head *old,
{
new->first = old->first;
if (new->first)
- new->first->pprev = &new->first;
- old->first = NULL;
+ WRITE_ONCE(new->first->pprev, &new->first);
+ WRITE_ONCE(old->first, NULL);
}
#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h
index fa6e8471bd..b63b0589fa 100644
--- a/include/linux/list_nulls.h
+++ b/include/linux/list_nulls.h
@@ -95,7 +95,7 @@ static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
n->next = first;
WRITE_ONCE(n->pprev, &h->first);
- h->first = n;
+ WRITE_ONCE(h->first, n);
if (!is_a_nulls(first))
WRITE_ONCE(first->pprev, &n->next);
}
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index ba4c00dd80..c65121655b 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -138,7 +138,7 @@ static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
if (last) {
n->next = last->next;
- n->pprev = &last->next;
+ WRITE_ONCE(n->pprev, &last->next);
rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
} else {
hlist_nulls_add_head_rcu(n, h);
--
2.34.1
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2023-06-19 9:46 [PATCH] rcu: Add necessary WRITE_ONCE() Alan Huang
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