[PATCH 20/36] net, rds: convert rds_ib_device.refcount from atomic_t to refcount_t

From: Elena Reshetova
Date: Tue Jul 04 2017 - 08:57:02 EST


refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
net/rds/ib.c | 12 ++++++------
net/rds/ib.h | 2 +-
net/rds/ib_rdma.c | 4 ++--
3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/net/rds/ib.c b/net/rds/ib.c
index 7a64c8d..a0954ac 100644
--- a/net/rds/ib.c
+++ b/net/rds/ib.c
@@ -118,8 +118,8 @@ static void rds_ib_dev_free(struct work_struct *work)

void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
{
- BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
- if (atomic_dec_and_test(&rds_ibdev->refcount))
+ BUG_ON(refcount_read(&rds_ibdev->refcount) == 0);
+ if (refcount_dec_and_test(&rds_ibdev->refcount))
queue_work(rds_wq, &rds_ibdev->free_work);
}

@@ -137,7 +137,7 @@ static void rds_ib_add_one(struct ib_device *device)
return;

spin_lock_init(&rds_ibdev->spinlock);
- atomic_set(&rds_ibdev->refcount, 1);
+ refcount_set(&rds_ibdev->refcount, 1);
INIT_WORK(&rds_ibdev->free_work, rds_ib_dev_free);

rds_ibdev->max_wrs = device->attrs.max_qp_wr;
@@ -205,10 +205,10 @@ static void rds_ib_add_one(struct ib_device *device)
down_write(&rds_ib_devices_lock);
list_add_tail_rcu(&rds_ibdev->list, &rds_ib_devices);
up_write(&rds_ib_devices_lock);
- atomic_inc(&rds_ibdev->refcount);
+ refcount_inc(&rds_ibdev->refcount);

ib_set_client_data(device, &rds_ib_client, rds_ibdev);
- atomic_inc(&rds_ibdev->refcount);
+ refcount_inc(&rds_ibdev->refcount);

rds_ib_nodev_connect();

@@ -239,7 +239,7 @@ struct rds_ib_device *rds_ib_get_client_data(struct ib_device *device)
rcu_read_lock();
rds_ibdev = ib_get_client_data(device, &rds_ib_client);
if (rds_ibdev)
- atomic_inc(&rds_ibdev->refcount);
+ refcount_inc(&rds_ibdev->refcount);
rcu_read_unlock();
return rds_ibdev;
}
diff --git a/net/rds/ib.h b/net/rds/ib.h
index ec55062..bf48224 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -230,7 +230,7 @@ struct rds_ib_device {
unsigned int max_initiator_depth;
unsigned int max_responder_resources;
spinlock_t spinlock; /* protect the above */
- atomic_t refcount;
+ refcount_t refcount;
struct work_struct free_work;
int *vector_load;
};
diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 977f698..9a3c54e 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -52,7 +52,7 @@ static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {
list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
if (i_ipaddr->ipaddr == ipaddr) {
- atomic_inc(&rds_ibdev->refcount);
+ refcount_inc(&rds_ibdev->refcount);
rcu_read_unlock();
return rds_ibdev;
}
@@ -134,7 +134,7 @@ void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *con
spin_unlock_irq(&ib_nodev_conns_lock);

ic->rds_ibdev = rds_ibdev;
- atomic_inc(&rds_ibdev->refcount);
+ refcount_inc(&rds_ibdev->refcount);
}

void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
--
2.7.4