On Mon, Jul 22, 2019 at 05:14:20PM +0200, Maksym Planeta wrote:
Need to ensure that kref_put does not run concurrently with the loop
inside rxe_pool_get_key.
Signed-off-by: Maksym Planeta <mplaneta@xxxxxxxxxxxxxxxxxxxx>
drivers/infiniband/sw/rxe/rxe_pool.c | 18 ++++++++++++++++++
drivers/infiniband/sw/rxe/rxe_pool.h | 4 +---
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index efa9bab01e02..30a887cf9200 100644
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -536,3 +536,21 @@ void *rxe_pool_get_key(struct rxe_pool *pool, void *key)
read_unlock_irqrestore(&pool->pool_lock, flags);
return node ? elem : NULL;
}
+
+static void rxe_dummy_release(struct kref *kref)
+{
+}
+
+void rxe_drop_ref(struct rxe_pool_entry *pelem)
+{
+ int res;
+ struct rxe_pool *pool = pelem->pool;
+ unsigned long flags;
+
+ write_lock_irqsave(&pool->pool_lock, flags);
+ res = kref_put(&pelem->ref_cnt, rxe_dummy_release);
+ write_unlock_irqrestore(&pool->pool_lock, flags);
This doesn't make sense..
If something is making the kref go to 0 while the node is still in the
RB tree then that is a bug.
You should never need to add locking around a kref_put.
Jason