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Subject[PATCH 04/10] Protect kref_put with the lock
Date
Need to ensure that kref_put does not run concurrently with the loop
inside rxe_pool_get_key.

Signed-off-by: Maksym Planeta <mplaneta@os.inf.tu-dresden.de>
---
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
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ 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);
+ if (res) {
+ rxe_elem_release(&pelem->ref_cnt);
+ }
+}
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
index 5c6a9429f541..b90cc84c5511 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.h
+++ b/drivers/infiniband/sw/rxe/rxe_pool.h
@@ -166,8 +166,6 @@ static inline void rxe_add_ref(struct rxe_pool_entry *pelem) {
}

/* drop a reference on an object */
-static inline void rxe_drop_ref(struct rxe_pool_entry *pelem) {
- kref_put(&pelem->ref_cnt, rxe_elem_release);
-}
+void rxe_drop_ref(struct rxe_pool_entry *pelem);

#endif /* RXE_POOL_H */
--
2.20.1
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