Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2021-06-28

The following pull-request contains BPF updates for your *net-next* tree.

We've added 37 non-merge commits during the last 12 day(s) which contain
a total of 56 files changed, 394 insertions(+), 380 deletions(-).

The main changes are:

1) XDP driver RCU cleanups, from Toke Høiland-Jørgensen and Paul E. McKenney.

2) Fix bpf_skb_change_proto() IPv4/v6 GSO handling, from Maciej Żenczykowski.

3) Fix false positive kmemleak report for BPF ringbuf alloc, from Rustam Kovhaev.

4) Fix x86 JIT's extable offset calculation for PROBE_LDX NULL, from Ravi Bangoria.

5) Enable libbpf fallback probing with tracing under RHEL7, from Jonathan Edwards.

6) Clean up x86 JIT to remove unused cnt tracking from EMIT macro, from Jiri Olsa.

7) Netlink cleanups for libbpf to please Coverity, from Kumar Kartikeya Dwivedi.

8) Allow to retrieve ancestor cgroup id in tracing programs, from Namhyung Kim.

9) Fix lirc BPF program query to use user-provided prog_cnt, from Sean Young.

10) Add initial libbpf doc including generated kdoc for its API, from Grant Seltzer.

11) Make xdp_rxq_info_unreg_mem_model() more robust, from Jakub Kicinski.

12) Fix up bpfilter startup log-level to info level, from Gary Lin.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 303 insertions, 37 deletions

diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst
index 1030119294d0..01cc21f17f7b 100644
--- a/Documentation/RCU/checklist.rst
+++ b/Documentation/RCU/checklist.rst
@@ -211,27 +211,40 @@ over a rather long period of time, but improvements are always welcome!
 	of the system, especially to real-time workloads running on
 	the rest of the system.
 
-7.	As of v4.20, a given kernel implements only one RCU flavor,
-	which is RCU-sched for PREEMPTION=n and RCU-preempt for PREEMPTION=y.
-	If the updater uses call_rcu() or synchronize_rcu(),
-	then the corresponding readers may use rcu_read_lock() and
-	rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
-	or any pair of primitives that disables and re-enables preemption,
-	for example, rcu_read_lock_sched() and rcu_read_unlock_sched().
-	If the updater uses synchronize_srcu() or call_srcu(),
-	then the corresponding readers must use srcu_read_lock() and
-	srcu_read_unlock(), and with the same srcu_struct.  The rules for
-	the expedited primitives are the same as for their non-expedited
-	counterparts.  Mixing things up will result in confusion and
-	broken kernels, and has even resulted in an exploitable security
-	issue.
-
-	One exception to this rule: rcu_read_lock() and rcu_read_unlock()
-	may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
-	in cases where local bottom halves are already known to be
-	disabled, for example, in irq or softirq context.  Commenting
-	such cases is a must, of course!  And the jury is still out on
-	whether the increased speed is worth it.
+7.	As of v4.20, a given kernel implements only one RCU flavor, which
+	is RCU-sched for PREEMPTION=n and RCU-preempt for PREEMPTION=y.
+	If the updater uses call_rcu() or synchronize_rcu(), then
+	the corresponding readers may use:  (1) rcu_read_lock() and
+	rcu_read_unlock(), (2) any pair of primitives that disables
+	and re-enables softirq, for example, rcu_read_lock_bh() and
+	rcu_read_unlock_bh(), or (3) any pair of primitives that disables
+	and re-enables preemption, for example, rcu_read_lock_sched() and
+	rcu_read_unlock_sched().  If the updater uses synchronize_srcu()
+	or call_srcu(), then the corresponding readers must use
+	srcu_read_lock() and srcu_read_unlock(), and with the same
+	srcu_struct.  The rules for the expedited RCU grace-period-wait
+	primitives are the same as for their non-expedited counterparts.
+
+	If the updater uses call_rcu_tasks() or synchronize_rcu_tasks(),
+	then the readers must refrain from executing voluntary
+	context switches, that is, from blocking.  If the updater uses
+	call_rcu_tasks_trace() or synchronize_rcu_tasks_trace(), then
+	the corresponding readers must use rcu_read_lock_trace() and
+	rcu_read_unlock_trace().  If an updater uses call_rcu_tasks_rude()
+	or synchronize_rcu_tasks_rude(), then the corresponding readers
+	must use anything that disables interrupts.
+
+	Mixing things up will result in confusion and broken kernels, and
+	has even resulted in an exploitable security issue.  Therefore,
+	when using non-obvious pairs of primitives, commenting is
+	of course a must.  One example of non-obvious pairing is
+	the XDP feature in networking, which calls BPF programs from
+	network-driver NAPI (softirq) context.	BPF relies heavily on RCU
+	protection for its data structures, but because the BPF program
+	invocation happens entirely within a single local_bh_disable()
+	section in a NAPI poll cycle, this usage is safe.  The reason
+	that this usage is safe is that readers can use anything that
+	disables BH when updaters use call_rcu() or synchronize_rcu().
 
 8.	Although synchronize_rcu() is slower than is call_rcu(), it
 	usually results in simpler code.  So, unless update performance is
diff --git a/Documentation/bpf/index.rst b/Documentation/bpf/index.rst
index 93e8cf12a6d4..baea6c2abba5 100644
--- a/Documentation/bpf/index.rst
+++ b/Documentation/bpf/index.rst
@@ -12,6 +12,19 @@ BPF instruction-set.
 The Cilium project also maintains a `BPF and XDP Reference Guide`_
 that goes into great technical depth about the BPF Architecture.
 
+libbpf
+======
+
+Libbpf is a userspace library for loading and interacting with bpf programs.
+
+.. toctree::
+   :maxdepth: 1
+
+   libbpf/libbpf
+   libbpf/libbpf_api
+   libbpf/libbpf_build
+   libbpf/libbpf_naming_convention
+
 BPF Type Format (BTF)
 =====================
 
diff --git a/Documentation/bpf/libbpf/libbpf.rst b/Documentation/bpf/libbpf/libbpf.rst
new file mode 100644
index 000000000000..1b1e61d5ead1
--- /dev/null
+++ b/Documentation/bpf/libbpf/libbpf.rst
@@ -0,0 +1,14 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+libbpf
+======
+
+This is documentation for libbpf, a userspace library for loading and
+interacting with bpf programs.
+
+All general BPF questions, including kernel functionality, libbpf APIs and
+their application, should be sent to bpf@vger.kernel.org mailing list.
+You can `subscribe <http://vger.kernel.org/vger-lists.html#bpf>`_ to the
+mailing list search its `archive <https://lore.kernel.org/bpf/>`_.
+Please search the archive before asking new questions. It very well might
+be that this was already addressed or answered before.
diff --git a/Documentation/bpf/libbpf/libbpf_api.rst b/Documentation/bpf/libbpf/libbpf_api.rst
new file mode 100644
index 000000000000..f07eecd054da
--- /dev/null
+++ b/Documentation/bpf/libbpf/libbpf_api.rst
@@ -0,0 +1,27 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+API
+===
+
+This documentation is autogenerated from header files in libbpf, tools/lib/bpf
+
+.. kernel-doc:: tools/lib/bpf/libbpf.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/bpf.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/btf.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/xsk.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/bpf_tracing.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/bpf_core_read.h
+   :internal:
+
+.. kernel-doc:: tools/lib/bpf/bpf_endian.h
+   :internal:
\ No newline at end of file
diff --git a/Documentation/bpf/libbpf/libbpf_build.rst b/Documentation/bpf/libbpf/libbpf_build.rst
new file mode 100644
index 000000000000..8e8c23e8093d
--- /dev/null
+++ b/Documentation/bpf/libbpf/libbpf_build.rst
@@ -0,0 +1,37 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+Building libbpf
+===============
+
+libelf and zlib are internal dependencies of libbpf and thus are required to link
+against and must be installed on the system for applications to work.
+pkg-config is used by default to find libelf, and the program called
+can be overridden with PKG_CONFIG.
+
+If using pkg-config at build time is not desired, it can be disabled by
+setting NO_PKG_CONFIG=1 when calling make.
+
+To build both static libbpf.a and shared libbpf.so:
+
+.. code-block:: bash
+
+    $ cd src
+    $ make
+
+To build only static libbpf.a library in directory build/ and install them
+together with libbpf headers in a staging directory root/:
+
+.. code-block:: bash
+
+    $ cd src
+    $ mkdir build root
+    $ BUILD_STATIC_ONLY=y OBJDIR=build DESTDIR=root make install
+
+To build both static libbpf.a and shared libbpf.so against a custom libelf
+dependency installed in /build/root/ and install them together with libbpf
+headers in a build directory /build/root/:
+
+.. code-block:: bash
+
+    $ cd src
+    $ PKG_CONFIG_PATH=/build/root/lib64/pkgconfig DESTDIR=/build/root make
\ No newline at end of file
diff --git a/Documentation/bpf/libbpf/libbpf_naming_convention.rst b/Documentation/bpf/libbpf/libbpf_naming_convention.rst
new file mode 100644
index 000000000000..3de1d51e41da
--- /dev/null
+++ b/Documentation/bpf/libbpf/libbpf_naming_convention.rst
@@ -0,0 +1,162 @@
+.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+API naming convention
+=====================
+
+libbpf API provides access to a few logically separated groups of
+functions and types. Every group has its own naming convention
+described here. It's recommended to follow these conventions whenever a
+new function or type is added to keep libbpf API clean and consistent.
+
+All types and functions provided by libbpf API should have one of the
+following prefixes: ``bpf_``, ``btf_``, ``libbpf_``, ``xsk_``,
+``btf_dump_``, ``ring_buffer_``, ``perf_buffer_``.
+
+System call wrappers
+--------------------
+
+System call wrappers are simple wrappers for commands supported by
+sys_bpf system call. These wrappers should go to ``bpf.h`` header file
+and map one to one to corresponding commands.
+
+For example ``bpf_map_lookup_elem`` wraps ``BPF_MAP_LOOKUP_ELEM``
+command of sys_bpf, ``bpf_prog_attach`` wraps ``BPF_PROG_ATTACH``, etc.
+
+Objects
+-------
+
+Another class of types and functions provided by libbpf API is "objects"
+and functions to work with them. Objects are high-level abstractions
+such as BPF program or BPF map. They're represented by corresponding
+structures such as ``struct bpf_object``, ``struct bpf_program``,
+``struct bpf_map``, etc.
+
+Structures are forward declared and access to their fields should be
+provided via corresponding getters and setters rather than directly.
+
+These objects are associated with corresponding parts of ELF object that
+contains compiled BPF programs.
+
+For example ``struct bpf_object`` represents ELF object itself created
+from an ELF file or from a buffer, ``struct bpf_program`` represents a
+program in ELF object and ``struct bpf_map`` is a map.
+
+Functions that work with an object have names built from object name,
+double underscore and part that describes function purpose.
+
+For example ``bpf_object__open`` consists of the name of corresponding
+object, ``bpf_object``, double underscore and ``open`` that defines the
+purpose of the function to open ELF file and create ``bpf_object`` from
+it.
+
+All objects and corresponding functions other than BTF related should go
+to ``libbpf.h``. BTF types and functions should go to ``btf.h``.
+
+Auxiliary functions
+-------------------
+
+Auxiliary functions and types that don't fit well in any of categories
+described above should have ``libbpf_`` prefix, e.g.
+``libbpf_get_error`` or ``libbpf_prog_type_by_name``.
+
+AF_XDP functions
+-------------------
+
+AF_XDP functions should have an ``xsk_`` prefix, e.g.
+``xsk_umem__get_data`` or ``xsk_umem__create``. The interface consists
+of both low-level ring access functions and high-level configuration
+functions. These can be mixed and matched. Note that these functions
+are not reentrant for performance reasons.
+
+ABI
+==========
+
+libbpf can be both linked statically or used as DSO. To avoid possible
+conflicts with other libraries an application is linked with, all
+non-static libbpf symbols should have one of the prefixes mentioned in
+API documentation above. See API naming convention to choose the right
+name for a new symbol.
+
+Symbol visibility
+-----------------
+
+libbpf follow the model when all global symbols have visibility "hidden"
+by default and to make a symbol visible it has to be explicitly
+attributed with ``LIBBPF_API`` macro. For example:
+
+.. code-block:: c
+
+        LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id);
+
+This prevents from accidentally exporting a symbol, that is not supposed
+to be a part of ABI what, in turn, improves both libbpf developer- and
+user-experiences.
+
+ABI versionning
+---------------
+
+To make future ABI extensions possible libbpf ABI is versioned.
+Versioning is implemented by ``libbpf.map`` version script that is
+passed to linker.
+
+Version name is ``LIBBPF_`` prefix + three-component numeric version,
+starting from ``0.0.1``.
+
+Every time ABI is being changed, e.g. because a new symbol is added or
+semantic of existing symbol is changed, ABI version should be bumped.
+This bump in ABI version is at most once per kernel development cycle.
+
+For example, if current state of ``libbpf.map`` is:
+
+.. code-block:: c
+
+        LIBBPF_0.0.1 {
+        	global:
+                        bpf_func_a;
+                        bpf_func_b;
+        	local:
+        		\*;
+        };
+
+, and a new symbol ``bpf_func_c`` is being introduced, then
+``libbpf.map`` should be changed like this:
+
+.. code-block:: c
+
+        LIBBPF_0.0.1 {
+        	global:
+                        bpf_func_a;
+                        bpf_func_b;
+        	local:
+        		\*;
+        };
+        LIBBPF_0.0.2 {
+                global:
+                        bpf_func_c;
+        } LIBBPF_0.0.1;
+
+, where new version ``LIBBPF_0.0.2`` depends on the previous
+``LIBBPF_0.0.1``.
+
+Format of version script and ways to handle ABI changes, including
+incompatible ones, described in details in [1].
+
+Stand-alone build
+-------------------
+
+Under https://github.com/libbpf/libbpf there is a (semi-)automated
+mirror of the mainline's version of libbpf for a stand-alone build.
+
+However, all changes to libbpf's code base must be upstreamed through
+the mainline kernel tree.
+
+License
+-------------------
+
+libbpf is dual-licensed under LGPL 2.1 and BSD 2-Clause.
+
+Links
+-------------------
+
+[1] https://www.akkadia.org/drepper/dsohowto.pdf
+    (Chapter 3. Maintaining APIs and ABIs).
diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst
index 2ccc5644cc98..42576880aa4a 100644
--- a/Documentation/networking/af_xdp.rst
+++ b/Documentation/networking/af_xdp.rst
@@ -290,19 +290,19 @@ round-robin example of distributing packets is shown below:
    #define MAX_SOCKS 16
 
    struct {
-        __uint(type, BPF_MAP_TYPE_XSKMAP);
-        __uint(max_entries, MAX_SOCKS);
-        __uint(key_size, sizeof(int));
-        __uint(value_size, sizeof(int));
+       __uint(type, BPF_MAP_TYPE_XSKMAP);
+       __uint(max_entries, MAX_SOCKS);
+       __uint(key_size, sizeof(int));
+       __uint(value_size, sizeof(int));
    } xsks_map SEC(".maps");
 
    static unsigned int rr;
 
    SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
    {
-	rr = (rr + 1) & (MAX_SOCKS - 1);
+       rr = (rr + 1) & (MAX_SOCKS - 1);
 
-	return bpf_redirect_map(&xsks_map, rr, XDP_DROP);
+       return bpf_redirect_map(&xsks_map, rr, XDP_DROP);
    }
 
 Note, that since there is only a single set of FILL and COMPLETION
@@ -379,7 +379,7 @@ would look like this for the TX path:
 .. code-block:: c
 
    if (xsk_ring_prod__needs_wakeup(&my_tx_ring))
-      sendto(xsk_socket__fd(xsk_handle), NULL, 0, MSG_DONTWAIT, NULL, 0);
+       sendto(xsk_socket__fd(xsk_handle), NULL, 0, MSG_DONTWAIT, NULL, 0);
 
 I.e., only use the syscall if the flag is set.
 
@@ -442,9 +442,9 @@ purposes. The supported statistics are shown below:
 .. code-block:: c
 
    struct xdp_statistics {
-	  __u64 rx_dropped; /* Dropped for reasons other than invalid desc */
-	  __u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
-	  __u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
+       __u64 rx_dropped; /* Dropped for reasons other than invalid desc */
+       __u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
+       __u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
    };
 
 XDP_OPTIONS getsockopt
@@ -483,15 +483,15 @@ like this:
 .. code-block:: c
 
     // struct xdp_rxtx_ring {
-    // 	__u32 *producer;
-    // 	__u32 *consumer;
-    // 	struct xdp_desc *desc;
+    //     __u32 *producer;
+    //     __u32 *consumer;
+    //     struct xdp_desc *desc;
     // };
 
     // struct xdp_umem_ring {
-    // 	__u32 *producer;
-    // 	__u32 *consumer;
-    // 	__u64 *desc;
+    //     __u32 *producer;
+    //     __u32 *consumer;
+    //     __u64 *desc;
     // };
 
     // typedef struct xdp_rxtx_ring RING;