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authorJakub Kicinski <kuba@kernel.org>2024-03-03 07:50:59 +0300
committerJakub Kicinski <kuba@kernel.org>2024-03-03 07:50:59 +0300
commit4b2765ae410abf01154cf97876384d8a58c43953 (patch)
tree6f5cdb7a5085b67c90244b2cbaeaa96bf401e17c /Documentation/networking
parente960825709330cb199d209740326cec37e8c419d (diff)
parent0270d69121ba7fbc449a386f989b9b7b5eaebde3 (diff)
downloadlinux-4b2765ae410abf01154cf97876384d8a58c43953.tar.xz
Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says: ==================== pull-request: bpf-next 2024-02-29 We've added 119 non-merge commits during the last 32 day(s) which contain a total of 150 files changed, 3589 insertions(+), 995 deletions(-). The main changes are: 1) Extend the BPF verifier to enable static subprog calls in spin lock critical sections, from Kumar Kartikeya Dwivedi. 2) Fix confusing and incorrect inference of PTR_TO_CTX argument type in BPF global subprogs, from Andrii Nakryiko. 3) Larger batch of riscv BPF JIT improvements and enabling inlining of the bpf_kptr_xchg() for RV64, from Pu Lehui. 4) Allow skeleton users to change the values of the fields in struct_ops maps at runtime, from Kui-Feng Lee. 5) Extend the verifier's capabilities of tracking scalars when they are spilled to stack, especially when the spill or fill is narrowing, from Maxim Mikityanskiy & Eduard Zingerman. 6) Various BPF selftest improvements to fix errors under gcc BPF backend, from Jose E. Marchesi. 7) Avoid module loading failure when the module trying to register a struct_ops has its BTF section stripped, from Geliang Tang. 8) Annotate all kfuncs in .BTF_ids section which eventually allows for automatic kfunc prototype generation from bpftool, from Daniel Xu. 9) Several updates to the instruction-set.rst IETF standardization document, from Dave Thaler. 10) Shrink the size of struct bpf_map resp. bpf_array, from Alexei Starovoitov. 11) Initial small subset of BPF verifier prepwork for sleepable bpf_timer, from Benjamin Tissoires. 12) Fix bpftool to be more portable to musl libc by using POSIX's basename(), from Arnaldo Carvalho de Melo. 13) Add libbpf support to gcc in CORE macro definitions, from Cupertino Miranda. 14) Remove a duplicate type check in perf_event_bpf_event, from Florian Lehner. 15) Fix bpf_spin_{un,}lock BPF helpers to actually annotate them with notrace correctly, from Yonghong Song. 16) Replace the deprecated bpf_lpm_trie_key 0-length array with flexible array to fix build warnings, from Kees Cook. 17) Fix resolve_btfids cross-compilation to non host-native endianness, from Viktor Malik. * tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (119 commits) selftests/bpf: Test if shadow types work correctly. bpftool: Add an example for struct_ops map and shadow type. bpftool: Generated shadow variables for struct_ops maps. libbpf: Convert st_ops->data to shadow type. libbpf: Set btf_value_type_id of struct bpf_map for struct_ops. bpf: Replace bpf_lpm_trie_key 0-length array with flexible array bpf, arm64: use bpf_prog_pack for memory management arm64: patching: implement text_poke API bpf, arm64: support exceptions arm64: stacktrace: Implement arch_bpf_stack_walk() for the BPF JIT bpf: add is_async_callback_calling_insn() helper bpf: introduce in_sleepable() helper bpf: allow more maps in sleepable bpf programs selftests/bpf: Test case for lacking CFI stub functions. bpf: Check cfi_stubs before registering a struct_ops type. bpf: Clarify batch lookup/lookup_and_delete semantics bpf, docs: specify which BPF_ABS and BPF_IND fields were zero bpf, docs: Fix typos in instruction-set.rst selftests/bpf: update tcp_custom_syncookie to use scalar packet offset bpf: Shrink size of struct bpf_map/bpf_array. ... ==================== Link: https://lore.kernel.org/r/20240301001625.8800-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking')
-rw-r--r--Documentation/networking/af_xdp.rst33
1 files changed, 19 insertions, 14 deletions
diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst
index dceeb0d763aa..72da7057e4cf 100644
--- a/Documentation/networking/af_xdp.rst
+++ b/Documentation/networking/af_xdp.rst
@@ -329,23 +329,24 @@ XDP_SHARED_UMEM option and provide the initial socket's fd in the
sxdp_shared_umem_fd field as you registered the UMEM on that
socket. These two sockets will now share one and the same UMEM.
-There is no need to supply an XDP program like the one in the previous
-case where sockets were bound to the same queue id and
-device. Instead, use the NIC's packet steering capabilities to steer
-the packets to the right queue. In the previous example, there is only
-one queue shared among sockets, so the NIC cannot do this steering. It
-can only steer between queues.
-
-In libbpf, you need to use the xsk_socket__create_shared() API as it
-takes a reference to a FILL ring and a COMPLETION ring that will be
-created for you and bound to the shared UMEM. You can use this
-function for all the sockets you create, or you can use it for the
-second and following ones and use xsk_socket__create() for the first
-one. Both methods yield the same result.
+In this case, it is possible to use the NIC's packet steering
+capabilities to steer the packets to the right queue. This is not
+possible in the previous example as there is only one queue shared
+among sockets, so the NIC cannot do this steering as it can only steer
+between queues.
+
+In libxdp (or libbpf prior to version 1.0), you need to use the
+xsk_socket__create_shared() API as it takes a reference to a FILL ring
+and a COMPLETION ring that will be created for you and bound to the
+shared UMEM. You can use this function for all the sockets you create,
+or you can use it for the second and following ones and use
+xsk_socket__create() for the first one. Both methods yield the same
+result.
Note that a UMEM can be shared between sockets on the same queue id
and device, as well as between queues on the same device and between
-devices at the same time.
+devices at the same time. It is also possible to redirect to any
+socket as long as it is bound to the same umem with XDP_SHARED_UMEM.
XDP_USE_NEED_WAKEUP bind flag
-----------------------------
@@ -822,6 +823,10 @@ A: The short answer is no, that is not supported at the moment. The
switch, or other distribution mechanism, in your NIC to direct
traffic to the correct queue id and socket.
+ Note that if you are using the XDP_SHARED_UMEM option, it is
+ possible to switch traffic between any socket bound to the same
+ umem.
+
Q: My packets are sometimes corrupted. What is wrong?
A: Care has to be taken not to feed the same buffer in the UMEM into