[PATCH 5.5 159/189] Revert "RDMA/cma: Simplify rdma_resolve_addr() error flow"

[Greg Kroah-Hartman]

From: Parav Pandit <parav@xxxxxxxxxxxx>

commit e4103312d7b7afb8a3a7a842a33ef2b1856b2c0f upstream.

This reverts commit 219d2e9dfda9431b808c28d5efc74b404b95b638.

The call chain below requires the cm_id_priv's destination address to be
setup before performing rdma_bind_addr(). Otherwise source port allocation
fails as cma_port_is_unique() no longer sees the correct tuple to allow
duplicate users of the source port.

rdma_resolve_addr()
  cma_bind_addr()
    rdma_bind_addr()
      cma_get_port()
        cma_alloc_any_port()
          cma_port_is_unique() <- compared with zero daddr

This can result in false failures to connect, particularly if the source
port range is restricted.

Fixes: 219d2e9dfda9 ("RDMA/cma: Simplify rdma_resolve_addr() error flow")
Link: https://lore.kernel.org/r/20200212072635.682689-4-leon@xxxxxxxxxx
Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/core/cma.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -3182,19 +3182,26 @@ int rdma_resolve_addr(struct rdma_cm_id
 	int ret;
 
 	id_priv = container_of(id, struct rdma_id_private, id);
+	memcpy(cma_dst_addr(id_priv), dst_addr, rdma_addr_size(dst_addr));
 	if (id_priv->state == RDMA_CM_IDLE) {
 		ret = cma_bind_addr(id, src_addr, dst_addr);
-		if (ret)
+		if (ret) {
+			memset(cma_dst_addr(id_priv), 0,
+			       rdma_addr_size(dst_addr));
 			return ret;
+		}
 	}
 
-	if (cma_family(id_priv) != dst_addr->sa_family)
+	if (cma_family(id_priv) != dst_addr->sa_family) {
+		memset(cma_dst_addr(id_priv), 0, rdma_addr_size(dst_addr));
 		return -EINVAL;
+	}
 
-	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_ADDR_QUERY))
+	if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_BOUND, RDMA_CM_ADDR_QUERY)) {
+		memset(cma_dst_addr(id_priv), 0, rdma_addr_size(dst_addr));
 		return -EINVAL;
+	}
 
-	memcpy(cma_dst_addr(id_priv), dst_addr, rdma_addr_size(dst_addr));
 	if (cma_any_addr(dst_addr)) {
 		ret = cma_resolve_loopback(id_priv);
 	} else {