[PATCH 5.6 037/118] selftests: net: tcp_mmap: clear whole tcp_zerocopy_receive struct

[Greg Kroah-Hartman]

From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit bf5525f3a8e3248be5aa5defe5aaadd60e1c1ba1 ]

We added fields in tcp_zerocopy_receive structure,
so make sure to clear all fields to not pass garbage to the kernel.

We were lucky because recent additions added 'out' parameters,
still we need to clean our reference implementation, before folks
copy/paste it.

Fixes: c8856c051454 ("tcp-zerocopy: Return inq along with tcp receive zerocopy.")
Fixes: 33946518d493 ("tcp-zerocopy: Return sk_err (if set) along with tcp receive zerocopy.")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Arjun Roy <arjunroy@xxxxxxxxxx>
Cc: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Acked-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 tools/testing/selftests/net/tcp_mmap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/net/tcp_mmap.c
+++ b/tools/testing/selftests/net/tcp_mmap.c
@@ -165,9 +165,10 @@ void *child_thread(void *arg)
 			socklen_t zc_len = sizeof(zc);
 			int res;
 
+			memset(&zc, 0, sizeof(zc));
 			zc.address = (__u64)((unsigned long)addr);
 			zc.length = chunk_size;
-			zc.recv_skip_hint = 0;
+
 			res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,
 					 &zc, &zc_len);
 			if (res == -1)