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IB/rxe: Move refcounting earlier in rxe_send()

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The network stack will call nskb's destructor, rxe_skb_tx_dtor(), if the
packet gets dropped by ip_local_out()/ip6_local_out(). Thus we need to add
the QP ref before output to avoid extra dereferences during network
congestion. This could lead to unwanted destruction of the QP.

Fix up the skb_out accounting, too.

Fixes: fda85ce912 ("IB/rxe: Fix kernel panic from skb destructor")
Signed-off-by: Andrew Boyer <andrew.boyer@dell.com>
Acked-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Andrew Boyer 2017-08-28 16:11:49 -04:00 committed by Doug Ledford
parent 0208da90de
commit 9eb7f8e44d
1 changed files with 5 additions and 3 deletions
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8
drivers/infiniband/sw/rxe/rxe_net.c
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@ -460,12 +460,17 @@ int rxe_send(struct rxe_dev *rxe, struct rxe_pkt_info *pkt, struct sk_buff *skb)
nskb->destructor = rxe_skb_tx_dtor;
nskb->sk = pkt->qp->sk->sk;
rxe_add_ref(pkt->qp);
atomic_inc(&pkt->qp->skb_out);
if (av->network_type == RDMA_NETWORK_IPV4) {
err = ip_local_out(dev_net(skb_dst(skb)->dev), nskb->sk, nskb);
} else if (av->network_type == RDMA_NETWORK_IPV6) {
err = ip6_local_out(dev_net(skb_dst(skb)->dev), nskb->sk, nskb);
} else {
pr_err("Unknown layer 3 protocol: %d\n", av->network_type);
atomic_dec(&pkt->qp->skb_out);
rxe_drop_ref(pkt->qp);
kfree_skb(nskb);
return -EINVAL;
}
@ -475,10 +480,7 @@ int rxe_send(struct rxe_dev *rxe, struct rxe_pkt_info *pkt, struct sk_buff *skb)
return -EAGAIN;
}
rxe_add_ref(pkt->qp);
atomic_inc(&pkt->qp->skb_out);
kfree_skb(skb);
return 0;
}