Merge: bpf, xdp: update to 6.3

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/2583

Rebase bpf and xdp to 6.3.

Bugzilla: https://bugzilla.redhat.com/2178930

Signed-off-by: Viktor Malik <vmalik@redhat.com>

Approved-by: Rafael Aquini <aquini@redhat.com>
Approved-by: Artem Savkov <asavkov@redhat.com>
Approved-by: Jason Wang <jasowang@redhat.com>
Approved-by: Jiri Benc <jbenc@redhat.com>
Approved-by: Jan Stancek <jstancek@redhat.com>
Approved-by: Baoquan He <5820488-baoquan_he@users.noreply.gitlab.com>

Signed-off-by: Jan Stancek <jstancek@redhat.com>

Author: jstancek

Documentation/admin-guide/kernel-parameters.txt

@@ -555,6 +555,7 @@
 			Format: <string>
 			nosocket -- Disable socket memory accounting.
 			nokmem -- Disable kernel memory accounting.
+			nobpf -- Disable BPF memory accounting.
 
 	checkreqprot	[SELINUX] Set initial checkreqprot flag value.
 			Format: { "0" | "1" }

Documentation/bpf/bpf_design_QA.rst

@@ -208,6 +208,10 @@ data structures and compile with kernel internal headers. Both of these
 kernel internals are subject to change and can break with newer kernels
 such that the program needs to be adapted accordingly.
 
+New BPF functionality is generally added through the use of kfuncs instead of
+new helpers. Kfuncs are not considered part of the stable API, and have their own
+lifecycle expectations as described in :ref:`BPF_kfunc_lifecycle_expectations`.
+
 Q: Are tracepoints part of the stable ABI?
 ------------------------------------------
 A: NO. Tracepoints are tied to internal implementation details hence they are
@@ -236,8 +240,8 @@ A: NO. Classic BPF programs are converted into extend BPF instructions.
 
 Q: Can BPF call arbitrary kernel functions?
 -------------------------------------------
-A: NO. BPF programs can only call a set of helper functions which
-is defined for every program type.
+A: NO. BPF programs can only call specific functions exposed as BPF helpers or
+kfuncs. The set of available functions is defined for every program type.
 
 Q: Can BPF overwrite arbitrary kernel memory?
 ---------------------------------------------
@@ -263,7 +267,12 @@ Q: New functionality via kernel modules?
 Q: Can BPF functionality such as new program or map types, new
 helpers, etc be added out of kernel module code?
 
-A: NO.
+A: Yes, through kfuncs and kptrs
+
+The core BPF functionality such as program types, maps and helpers cannot be
+added to by modules. However, modules can expose functionality to BPF programs
+by exporting kfuncs (which may return pointers to module-internal data
+structures as kptrs).
 
 Q: Directly calling kernel function is an ABI?
 ----------------------------------------------
@@ -278,7 +287,8 @@ kernel functions have already been used by other kernel tcp
 cc (congestion-control) implementations.  If any of these kernel
 functions has changed, both the in-tree and out-of-tree kernel tcp cc
 implementations have to be changed.  The same goes for the bpf
-programs and they have to be adjusted accordingly.
+programs and they have to be adjusted accordingly. See
+:ref:`BPF_kfunc_lifecycle_expectations` for details.
 
 Q: Attaching to arbitrary kernel functions is an ABI?
 -----------------------------------------------------
@@ -340,6 +350,7 @@ compatibility for these features?
 
 A: NO.
 
-Unlike map value types, there are no stability guarantees for this case. The
-whole API to work with allocated objects and any support for special fields
-inside them is unstable (since it is exposed through kfuncs).
+Unlike map value types, the API to work with allocated objects and any support
+for special fields inside them is exposed through kfuncs, and thus has the same
+lifecycle expectations as the kfuncs themselves. See
+:ref:`BPF_kfunc_lifecycle_expectations` for details.

Documentation/bpf/bpf_devel_QA.rst

@@ -7,8 +7,8 @@ workflows related to reporting bugs, submitting patches, and queueing
 patches for stable kernels.
 
 For general information about submitting patches, please refer to
-`Documentation/process/`_. This document only describes additional specifics
-related to BPF.
+Documentation/process/submitting-patches.rst. This document only describes
+additional specifics related to BPF.
 
 .. contents::
     :local:
@@ -461,15 +461,15 @@ needed::
 
   $ sudo make run_tests
 
-See the kernels selftest `Documentation/dev-tools/kselftest.rst`_
-document for further documentation.
+See :doc:`kernel selftest documentation </dev-tools/kselftest>`
+for details.
 
 To maximize the number of tests passing, the .config of the kernel
 under test should match the config file fragment in
 tools/testing/selftests/bpf as closely as possible.
 
 Finally to ensure support for latest BPF Type Format features -
-discussed in `Documentation/bpf/btf.rst`_ - pahole version 1.16
+discussed in Documentation/bpf/btf.rst - pahole version 1.16
 is required for kernels built with CONFIG_DEBUG_INFO_BTF=y.
 pahole is delivered in the dwarves package or can be built
 from source at
@@ -684,12 +684,8 @@ when:
 
 
 .. Links
-.. _Documentation/process/: https://www.kernel.org/doc/html/latest/process/
 .. _netdev-FAQ: ../networking/netdev-FAQ.rst
 .. _selftests:
    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/
-.. _Documentation/dev-tools/kselftest.rst:
-   https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html
-.. _Documentation/bpf/btf.rst: btf.rst
 
 Happy BPF hacking!