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From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@gmail.com>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Yonghong Song" <yhs@fb.com>
Subject: [PATCH bpf v2] libbpf: Remove getsockopt() check for XDP_OPTIONS
Date: Mon, 16 Sep 2019 14:33:42 +0200	[thread overview]
Message-ID: <20190916123342.49928-1-toke@redhat.com> (raw)

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


             reply	other threads:[~2019-09-16 13:04 UTC|newest]

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

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