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* [PATCH bpf v2] libbpf: Remove getsockopt() check for XDP_OPTIONS
@ 2019-09-16 12:33 Toke Høiland-Jørgensen
  2019-09-17  4:12 ` Andrii Nakryiko
  2019-09-19 12:31 ` Daniel Borkmann
  0 siblings, 2 replies; 3+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-09-16 12:33 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, netdev, bpf
  Cc: Björn Töpel, Toke Høiland-Jørgensen, Yonghong Song

The xsk_socket__create() function fails and returns an error if it cannot
get the XDP_OPTIONS through getsockopt(). However, support for XDP_OPTIONS
was not added until kernel 5.3, so this means that creating XSK sockets
always fails on older kernels.

Since the option is just used to set the zero-copy flag in the xsk struct,
and that flag is not really used for anything yet, just remove the
getsockopt() call until a proper use for it is introduced.

Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
v2:
  - Remove the call entirely.
  
 tools/lib/bpf/xsk.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 680e63066cf3..14aea315c914 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -65,7 +65,6 @@ struct xsk_socket {
 	int xsks_map_fd;
 	__u32 queue_id;
 	char ifname[IFNAMSIZ];
-	bool zc;
 };
 
 struct xsk_nl_info {
@@ -481,7 +480,6 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
 	void *rx_map = NULL, *tx_map = NULL;
 	struct sockaddr_xdp sxdp = {};
 	struct xdp_mmap_offsets off;
-	struct xdp_options opts;
 	struct xsk_socket *xsk;
 	socklen_t optlen;
 	int err;
@@ -601,15 +599,6 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
 
 	xsk->prog_fd = -1;
 
-	optlen = sizeof(opts);
-	err = getsockopt(xsk->fd, SOL_XDP, XDP_OPTIONS, &opts, &optlen);
-	if (err) {
-		err = -errno;
-		goto out_mmap_tx;
-	}
-
-	xsk->zc = opts.flags & XDP_OPTIONS_ZEROCOPY;
-
 	if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
 		err = xsk_setup_xdp_prog(xsk);
 		if (err)
-- 
2.23.0


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-09-19 12:31 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-09-16 12:33 [PATCH bpf v2] libbpf: Remove getsockopt() check for XDP_OPTIONS Toke Høiland-Jørgensen
2019-09-17  4:12 ` Andrii Nakryiko
2019-09-19 12:31 ` Daniel Borkmann

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