From: Yonghong Song <yhs@fb.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: [PATCH] libbpf: Don't error out if getsockopt() fails for XDP_OPTIONS
Date: Mon, 9 Sep 2019 17:53:21 +0000 [thread overview]
Message-ID: <8e909219-a225-b242-aaa5-bee1180aed48@fb.com> (raw)
In-Reply-To: <20190909174619.1735-1-toke@redhat.com>
On 9/9/19 10:46 AM, Toke Høiland-Jørgensen wrote:
> 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,
> there really is no need to error out if the getsockopt() call fails.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
> tools/lib/bpf/xsk.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> index 680e63066cf3..598e487d9ce8 100644
> --- a/tools/lib/bpf/xsk.c
> +++ b/tools/lib/bpf/xsk.c
> @@ -603,12 +603,8 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
>
> 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 (!err)
> + xsk->zc = opts.flags & XDP_OPTIONS_ZEROCOPY;
>
> if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
> err = xsk_setup_xdp_prog(xsk);
Since 'zc' is not used by anybody, maybe all codes 'zc' related can be
removed? It can be added back back once there is an interface to use 'zc'?
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 842c4fd55859..24fa313524fb 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 {
@@ -491,7 +490,6 @@ 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;
@@ -611,15 +609,6 @@ 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)
next prev parent reply other threads:[~2019-09-09 17:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 17:46 [PATCH] libbpf: Don't error out if getsockopt() fails for XDP_OPTIONS Toke Høiland-Jørgensen
2019-09-09 17:53 ` Yonghong Song [this message]
2019-09-09 23:06 ` Toke Høiland-Jørgensen
2019-09-13 18:53 ` Yonghong Song
2019-09-16 5:09 ` Björn Töpel
2019-09-16 8:08 ` Daniel Borkmann
2019-09-16 12:31 ` Toke Høiland-Jørgensen
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