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| author | Michael S. Tsirkin <mst@redhat.com> | 2017-02-27 21:14:19 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-19 09:29:18 -0700 |
| commit | 48ac34666ff76843d8743db1cc78b303759916f1 (patch) | |
| tree | 4a44a13177bcdb5e513bda83d830480e4b26262b | |
| parent | d1e4f01d09b88c6df3e9f6b8ca5f1a3882069ccc (diff) | |
| download | lwn-48ac34666ff76843d8743db1cc78b303759916f1.tar.gz lwn-48ac34666ff76843d8743db1cc78b303759916f1.zip | |
hlist_add_tail_rcu disable sparse warning
sparse is unhappy about this code in hlist_add_tail_rcu:
struct hlist_node *i, *last = NULL;
for (i = hlist_first_rcu(h); i; i = hlist_next_rcu(i))
last = i;
This is because hlist_next_rcu and hlist_next_rcu return
__rcu pointers.
It's a false positive - it's a write side primitive and so
does not need to be called in a read side critical section.
The following trivial patch disables the warning
without changing the behaviour in any way.
Note: __hlist_for_each_rcu would also remove the warning but it would be
confusing since it calls rcu_derefence and is designed to run in the rcu
read side critical section.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | include/linux/rculist.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 4f7a9561b8c4..b1fd8bf85fdc 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -509,7 +509,8 @@ static inline void hlist_add_tail_rcu(struct hlist_node *n, { struct hlist_node *i, *last = NULL; - for (i = hlist_first_rcu(h); i; i = hlist_next_rcu(i)) + /* Note: write side code, so rcu accessors are not needed. */ + for (i = h->first; i; i = i->next) last = i; if (last) { |