On 2019/4/10 16:15, Leon Romanovsky wrote:
From: Parav Pandit <parav@xxxxxxxxxxxx>
Use rdma_read_gid_attr_ndev_rcu() to access netdevice attached to GID
entry under rcu lock.
This ensures that while working on the netdevice of the GID, it doesn't
get freed.
Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_net.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index c44139788afc..5a3474f9351b 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -458,7 +458,7 @@ struct sk_buff *rxe_init_packet(struct rxe_dev *rxe, struct rxe_av *av,
int paylen, struct rxe_pkt_info *pkt)
{
unsigned int hdr_len;
- struct sk_buff *skb;
+ struct sk_buff *skb = NULL;
In the following source code, skb is assigned before it is used. So is
it necessary to initialize it now?
Zhu Yanjun
struct net_device *ndev;
const struct ib_gid_attr *attr;
const int port_num = 1;
@@ -466,7 +466,6 @@ struct sk_buff *rxe_init_packet(struct rxe_dev *rxe, struct rxe_av *av,
attr = rdma_get_gid_attr(&rxe->ib_dev, port_num, av->grh.sgid_index);
if (IS_ERR(attr))
return NULL;
- ndev = attr->ndev;
if (av->network_type == RDMA_NETWORK_IPV4)
hdr_len = ETH_HLEN + sizeof(struct udphdr) +
@@ -475,16 +474,26 @@ struct sk_buff *rxe_init_packet(struct rxe_dev *rxe, struct rxe_av *av,
hdr_len = ETH_HLEN + sizeof(struct udphdr) +
sizeof(struct ipv6hdr);
+ rcu_read_lock();
+ ndev = rdma_read_gid_attr_ndev_rcu(attr);
+ if (IS_ERR(ndev)) {
+ rcu_read_unlock();
+ goto out;
+ }
skb = alloc_skb(paylen + hdr_len + LL_RESERVED_SPACE(ndev),
GFP_ATOMIC);
- if (unlikely(!skb))
+ if (unlikely(!skb)) {
+ rcu_read_unlock();
goto out;
+ }
skb_reserve(skb, hdr_len + LL_RESERVED_SPACE(ndev));
/* FIXME: hold reference to this netdev until life of this skb. */
skb->dev = ndev;
+ rcu_read_unlock();
+
if (av->network_type == RDMA_NETWORK_IPV4)
skb->protocol = htons(ETH_P_IP);
else
