[PATCH net-next] Documentation: xsk: correct the obsolete references and examples

[Jason Xing <kerneljasonxing@gmail.com>]

From: Jason Xing <kernelxing@tencent.com>

The modified lines are mainly related to the following commits[1][2]
which remove those tests and examples. Since samples/bpf has been
deprecated, we can refer to more examples that are easily searched
in the various xdp-projects.

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=f36600634
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=cfb5a2dbf14

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
 Documentation/networking/af_xdp.rst | 45 ++++++++---------------------
 1 file changed, 12 insertions(+), 33 deletions(-)

diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst
index dceeb0d763aa..37711619e89e 100644
--- a/Documentation/networking/af_xdp.rst
+++ b/Documentation/networking/af_xdp.rst
@@ -209,13 +209,10 @@ Libbpf
 
 Libbpf is a helper library for eBPF and XDP that makes using these
 technologies a lot simpler. It also contains specific helper functions
-in tools/lib/bpf/xsk.h for facilitating the use of AF_XDP. It
-contains two types of functions: those that can be used to make the
-setup of AF_XDP socket easier and ones that can be used in the data
-plane to access the rings safely and quickly. To see an example on how
-to use this API, please take a look at the sample application in
-samples/bpf/xdpsock_usr.c which uses libbpf for both setup and data
-plane operations.
+in ./tools/testing/selftests/bpf/xsk.h for facilitating the use of
+AF_XDP. It contains two types of functions: those that can be used to
+make the setup of AF_XDP socket easier and ones that can be used in the
+data plane to access the rings safely and quickly.
 
 We recommend that you use this library unless you have become a power
 user. It will make your program a lot simpler.
@@ -372,8 +369,7 @@ needs to explicitly notify the kernel to send any packets put on the
 TX ring. This can be accomplished either by a poll() call, as in the
 RX path, or by calling sendto().
 
-An example of how to use this flag can be found in
-samples/bpf/xdpsock_user.c. An example with the use of libbpf helpers
+An example with the use of libbpf helpers
 would look like this for the TX path:
 
 .. code-block:: c
@@ -551,10 +547,9 @@ Usage
 
 In order to use AF_XDP sockets two parts are needed. The
 user-space application and the XDP program. For a complete setup and
-usage example, please refer to the sample application. The user-space
-side is xdpsock_user.c and the XDP side is part of libbpf.
+usage example, please refer to the xdp-project.
 
-The XDP code sample included in tools/lib/bpf/xsk.c is the following:
+The XDP code sample is the following:
 
 .. code-block:: c
 
@@ -753,27 +748,11 @@ to facilitate extending a zero-copy driver with multi-buffer support.
 Sample application
 ==================
 
-There is a xdpsock benchmarking/test application included that
-demonstrates how to use AF_XDP sockets with private UMEMs. Say that
-you would like your UDP traffic from port 4242 to end up in queue 16,
-that we will enable AF_XDP on. Here, we use ethtool for this::
-
-      ethtool -N p3p2 rx-flow-hash udp4 fn
-      ethtool -N p3p2 flow-type udp4 src-port 4242 dst-port 4242 \
-          action 16
-
-Running the rxdrop benchmark in XDP_DRV mode can then be done
-using::
-
-      samples/bpf/xdpsock -i p3p2 -q 16 -r -N
-
-For XDP_SKB mode, use the switch "-S" instead of "-N" and all options
-can be displayed with "-h", as usual.
-
-This sample application uses libbpf to make the setup and usage of
-AF_XDP simpler. If you want to know how the raw uapi of AF_XDP is
-really used to make something more advanced, take a look at the libbpf
-code in tools/lib/bpf/xsk.[ch].
+Xdpsock benchmarking/test application can be found through googling
+the various xdp-project repositories connected to libxdp. If you want
+to know how the raw uapi of AF_XDP is really used to make something
+more advanced, take a look at the libbpf code in
+tools/testing/selftests/bpf/xsk.[ch].
 
 FAQ
 =======
-- 
2.41.3