[PATCH 5/7] IB/rxe: Fix destination cache for IPv6

Andrew Boyer
2017-07-25T13:39:26Z

To successfully match an IPv6 path, the path cookie must match. Store it
in the QP so that the IPv6 path can be reused.

Replace open-coded version of dst_check() with the actual call, fixing the
logic. The open-coded version skips the check call if dst->obsolete is 0
(DST_OBSOLETE_NONE), proceeding to replace the route. DST_OBSOLETE_NONE
means that the route may continue to be used, though.

Add dst_clone() in prepare_ipv6_hdr(). Otherwise the reference count goes
negative as packets complete.

Replace sk_dst_get()/dst_release() in rxe_qp_cleanup() with sk_dst_reset().
sk_dst_get() takes a new reference on dst, so the dst_release() doesn't
actually release the original reference, which was the design intent.

Remove unneeded initialization in prepare6().

Fixes: 4ed6ad1eb30e ("IB/rxe: Cache dst in QP instead of getting it...")
Signed-off-by: Andrew Boyer <andrew.boyer-8PEkshWhKlo@public.gmane.org>
---
drivers/infiniband/sw/rxe/rxe_net.c | 9 ++++++---
drivers/infiniband/sw/rxe/rxe_qp.c | 9 ++-------
drivers/infiniband/sw/rxe/rxe_verbs.h | 1 +
3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 0810f38..6aeda61 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -191,7 +191,7 @@ static struct dst_entry *rxe_find_route(struct rxe_dev *rxe,
if (qp_type(qp) == IB_QPT_RC)
dst = sk_dst_get(qp->sk->sk);

- if (!dst || !(dst->obsolete && dst->ops->check(dst, 0))) {
+ if (!dst || !dst_check(dst, qp->dst_cookie)) {
if (dst)
dst_release(dst);

@@ -209,6 +209,9 @@ static struct dst_entry *rxe_find_route(struct rxe_dev *rxe,
saddr6 = &av->sgid_addr._sockaddr_in6.sin6_addr;
daddr6 = &av->dgid_addr._sockaddr_in6.sin6_addr;
dst = rxe_find_route6(rxe->ndev, saddr6, daddr6);
+ if (dst)
+ qp->dst_cookie =
+ rt6_get_cookie((struct rt6_info *)dst);
}
}

@@ -337,7 +340,7 @@ static void prepare_ipv6_hdr(struct dst_entry *dst, struct sk_buff *skb,
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED
| IPSKB_REROUTED);
- skb_dst_set(skb, dst);
+ skb_dst_set(skb, dst_clone(dst));

__skb_push(skb, sizeof(*ip6h));
skb_reset_network_header(skb);
@@ -388,7 +391,7 @@ static int prepare6(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
struct sk_buff *skb, struct rxe_av *av)
{
struct rxe_qp *qp = pkt->qp;
- struct dst_entry *dst = NULL;
+ struct dst_entry *dst;
struct in6_addr *saddr = &av->sgid_addr._sockaddr_in6.sin6_addr;
struct in6_addr *daddr = &av->dgid_addr._sockaddr_in6.sin6_addr;

diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 80ccc7c..00bda93 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -851,13 +851,8 @@ void rxe_qp_cleanup(struct rxe_pool_entry *arg)
qp->resp.mr = NULL;
}

- if (qp_type(qp) == IB_QPT_RC) {
- struct dst_entry *dst = NULL;
-
- dst = sk_dst_get(qp->sk->sk);
- if (dst)
- dst_release(dst);
- }
+ if (qp_type(qp) == IB_QPT_RC)
+ sk_dst_reset(qp->sk->sk);

free_rd_atomic_resources(qp);

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index b09a9e2..0c2dbe4 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -248,6 +248,7 @@ struct rxe_qp {
struct rxe_rq rq;

struct socket *sk;
+ u32 dst_cookie;

struct rxe_av pri_av;
struct rxe_av alt_av;