FAILED: patch "[PATCH] IB/addr: Fix setting source address in addr6_resolve()" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Roland Dreier <[email protected]>
Date: Tue, 6 Jun 2017 09:22:00 -0700
Subject: [PATCH] IB/addr: Fix setting source address in addr6_resolve()

Commit eea40b8f624f ("infiniband: call ipv6 route lookup via the stub interface") introduced a regression in address resolution when connecting to IPv6 destination addresses. The old code called ip6_route_output(), while the new code calls ipv6_stub->ipv6_dst_lookup(). The two are almost the same, except that ipv6_dst_lookup() also calls ip6_route_get_saddr() if the source address is in6addr_any.

This means that the test of ipv6_addr_any(&fl6.saddr) now never succeeds, and so we never copy the source address out. This ends up causing rdma_resolve_addr() to fail, because without a resolved source address, cma_acquire_dev() will fail to find an RDMA device to use. For me, this causes connecting to an NVMe over Fabrics target via RoCE / IPv6 to fail.

Fix this by copying out fl6.saddr if ipv6_addr_any() is true for the original source address passed into addr6_resolve(). We can drop our call to ipv6_dev_get_saddr() because ipv6_dst_lookup() already does that work.

index 02971e239a18..ece6926fa2e6 100644
@@ -449,12 +449,7 @@ static int addr6_resolve(struct sockaddr_in6 *src_in,
 		return ret;
 
 	rt = (struct rt6_info *)dst;
-	if (ipv6_addr_any(&fl6.saddr)) {
-		ret = ipv6_dev_get_saddr(addr->net, ip6_dst_idev(dst)->dev,
-					 &fl6.daddr, 0, &fl6.saddr);
-		if (ret)
-			goto put;
-
+	if (ipv6_addr_any(&src_in->sin6_addr)) {
 		src_in->sin6_family = AF_INET6;
 		src_in->sin6_addr = fl6.saddr;
 	}

@@ -471,9 +466,6 @@ static int addr6_resolve(struct sockaddr_in6 *src_in,
 
 	*pdst = dst;
 	return 0;
-put:
-	dst_release(dst);
-	return ret;
 }
 #else
 static int addr6_resolve(struct sockaddr_in6 *src_in,