Tooling that populates the SOCK{MAP,HASH} with sockets from user-space
needs a way to inspect its contents. Returning the struct sock * that the
map holds to user-space is neither safe nor useful. An approach established
by REUSEPORT_SOCKARRAY is to return a socket cookie (a unique identifier)
instead.

Since socket cookies are u64 values, SOCK{MAP,HASH} need to support such a
value size for lookup to be possible. This requires special handling on
update, though. Attempts to do a lookup on a map holding u32 values will be
met with ENOSPC error.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-7-jakub@cloudflare.com

Now that sockmap/sockhash can hold listening sockets, when setting up the
psock we will (i) grab references to verdict/parser progs, and (2) override
socket upcalls sk_data_ready and sk_write_space.

However, since we cannot redirect to listening sockets so we don't need to
link the socket to the BPF progs. And more importantly we don't want the
listening socket to have overridden upcalls because they would get
inherited by child sockets cloned from it.

Introduce a separate initialization path for listening sockets that does
not change the upcalls and ignores the BPF progs.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-6-jakub@cloudflare.com

In order for sockmap/sockhash types to become generic collections for
storing TCP sockets we need to loosen the checks during map update, while
tightening the checks in redirect helpers.

Currently sock{map,hash} require the TCP socket to be in established state,
which prevents inserting listening sockets.

Change the update pre-checks so the socket can also be in listening state.

Since it doesn't make sense to redirect with sock{map,hash} to listening
sockets, add appropriate socket state checks to BPF redirect helpers too.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-5-jakub@cloudflare.com

Prepare for cloning listening sockets that have their protocol callbacks
overridden by sk_msg. Child sockets must not inherit parent callbacks that
access state stored in sk_user_data owned by the parent.

Restore the child socket protocol callbacks before it gets hashed and any
of the callbacks can get invoked.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-4-jakub@cloudflare.com

sk_user_data can hold a pointer to an object that is not intended to be
shared between the parent socket and the child that gets a pointer copy on
clone. This is the case when sk_user_data points at reference-counted
object, like struct sk_psock.

One way to resolve it is to tag the pointer with a no-copy flag by
repurposing its lowest bit. Based on the bit-flag value we clear the child
sk_user_data pointer after cloning the parent socket.

The no-copy flag is stored in the pointer itself as opposed to externally,
say in socket flags, to guarantee that the pointer and the flag are copied
from parent to child socket in an atomic fashion. Parent socket state is
subject to change while copying, we don't hold any locks at that time.

This approach relies on an assumption that sk_user_data holds a pointer to
an object aligned at least 2 bytes. A manual audit of existing users of
rcu_dereference_sk_user_data helper confirms our assumption.

Also, an RCU-protected sk_user_data is not likely to hold a pointer to a
char value or a pathological case of "struct { char c; }". To be safe, warn
when the flag-bit is set when setting sk_user_data to catch any future
misuses.

It is worth considering why clearing sk_user_data unconditionally is not an
option. There exist users, DRBD, NVMe, and Xen drivers being among them,
that rely on the pointer being copied when cloning the listening socket.

Potentially we could distinguish these users by checking if the listening
socket has been created in kernel-space via sock_create_kern, and hence has
sk_kern_sock flag set. However, this is not the case for NVMe and Xen
drivers, which create sockets without marking them as belonging to the
kernel.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200218171023.844439-3-jakub@cloudflare.com

sk_msg and ULP frameworks override protocol callbacks pointer in
sk->sk_prot, while tcp accesses it locklessly when cloning the listening
socket, that is with neither sk_lock nor sk_callback_lock held.

Once we enable use of listening sockets with sockmap (and hence sk_msg),
there will be shared access to sk->sk_prot if socket is getting cloned
while being inserted/deleted to/from the sockmap from another CPU:

Read side:

tcp_v4_rcv
  sk = __inet_lookup_skb(...)
  tcp_check_req(sk)
    inet_csk(sk)->icsk_af_ops->syn_recv_sock
      tcp_v4_syn_recv_sock
        tcp_create_openreq_child
          inet_csk_clone_lock
            sk_clone_lock
              READ_ONCE(sk->sk_prot)

Write side:

sock_map_ops->map_update_elem
  sock_map_update_elem
    sock_map_update_common
      sock_map_link_no_progs
        tcp_bpf_init
          tcp_bpf_update_sk_prot
            sk_psock_update_proto
              WRITE_ONCE(sk->sk_prot, ops)

sock_map_ops->map_delete_elem
  sock_map_delete_elem
    __sock_map_delete
     sock_map_unref
       sk_psock_put
         sk_psock_drop
           sk_psock_restore_proto
             tcp_update_ulp
               WRITE_ONCE(sk->sk_prot, proto)

Mark the shared access with READ_ONCE/WRITE_ONCE annotations.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200218171023.844439-2-jakub@cloudflare.com

bpf now has its own mailing list bpf@vger.kernel.org.
Update the bpf_devel_QA.rst file to reflect this.

Also llvm has switch to github with llvm and clang
in the same repo https://github.com/llvm/llvm-project.git.
Update the QA file with newer build instructions.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200221004354.930952-1-yhs@fb.com

Libbpf's Travis CI tests caught this issue. Ensure bpf_link and bpf_object
clean up is performed correctly.

Fixes: d633d579 ("selftest/bpf: Add test for allowed trampolines count")
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20200220230546.769250-1-andriin@fb.com

Eelco Chaudron says:

====================
Currently when you want to attach a trace program to a bpf program
the section name needs to match the tracepoint/function semantics.

However the addition of the bpf_program__set_attach_target() API
allows you to specify the tracepoint/function dynamically.

The call flow would look something like this:

  xdp_fd = bpf_prog_get_fd_by_id(id);
  trace_obj = bpf_object__open_file("func.o", NULL);
  prog = bpf_object__find_program_by_title(trace_obj,
                                           "fentry/myfunc");
  bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY);
  bpf_program__set_attach_target(prog, xdp_fd,
                                 "xdpfilt_blk_all");
  bpf_object__load(trace_obj)

v1 -> v2: Remove requirement for attach type hint in API
v2 -> v3: Moved common warning to __find_vmlinux_btf_id, requested by Andrii
          Updated the xdp_bpf2bpf test to use this new API
v3 -> v4: Split up patch, update libbpf.map version
v4 -> v5: Fix return code, and prog assignment in test case
====================
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Use the new bpf_program__set_attach_target() API in the xdp_bpf2bpf
selftest so it can be referenced as an example on how to use it.
Signed-off-by: NEelco Chaudron <echaudro@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/158220520562.127661.14289388017034825841.stgit@xdp-tutorial

Currently when you want to attach a trace program to a bpf program
the section name needs to match the tracepoint/function semantics.

However the addition of the bpf_program__set_attach_target() API
allows you to specify the tracepoint/function dynamically.

The call flow would look something like this:

  xdp_fd = bpf_prog_get_fd_by_id(id);
  trace_obj = bpf_object__open_file("func.o", NULL);
  prog = bpf_object__find_program_by_title(trace_obj,
                                           "fentry/myfunc");
  bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY);
  bpf_program__set_attach_target(prog, xdp_fd,
                                 "xdpfilt_blk_all");
  bpf_object__load(trace_obj)
Signed-off-by: NEelco Chaudron <echaudro@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158220519486.127661.7964708960649051384.stgit@xdp-tutorial

New development cycles starts, bump to v0.0.8.
Signed-off-by: NEelco Chaudron <echaudro@redhat.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/158220518424.127661.8278643006567775528.stgit@xdp-tutorial

If BPF program is using BTF-defined maps, BTF is required only for
libbpf itself to process map definitions. If after that BTF fails to
be loaded into kernel (e.g., if it doesn't support BTF at all), this
shouldn't prevent valid BPF program from loading. Existing
retry-without-BTF logic for creating maps will succeed to create such
maps without any problems. So, presence of .maps section shouldn't make
BTF required for kernel. Update the check accordingly.

Validated by ensuring simple BPF program with BTF-defined maps is still
loaded on old kernel without BTF support and map is correctly parsed and
created.

Fixes: abd29c93 ("libbpf: allow specifying map definitions using BTF")
Reported-by: NJulia Kartseva <hex@fb.com>
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200220062635.1497872-1-andriin@fb.com

The selftests fails to build with:
tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c: In function ‘test_sockmap_ktls_disconnect_after_delete’:
tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c:72:37: error: ‘TCP_ULP’ undeclared (first use in this function)
   72 |  err = setsockopt(cli, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls"));
      |                                     ^~~~~~~

Similar to commit that fixes build of sockmap_basic.c on systems with old
/usr/include fix the build of sockmap_ktls.c

Fixes: d1ba1204 ("selftests/bpf: Test unhashing kTLS socket after removing from map")
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200219205514.3353788-1-ast@kernel.org

The latest llvm supports cpu version v3, which is cpu version v1
plus some additional 64bit jmp insns and 32bit jmp insn support.

In selftests/bpf Makefile, the llvm flag -mcpu=probe did runtime
probe into the host system. Depending on compilation environments,
it is possible that runtime probe may fail, e.g., due to
memlock issue. This will cause generated code with cpu version v1.
This may cause confusion as the same compiler and the same C code
generates different byte codes in different environment.

Let us change the llvm flag -mcpu=probe to -mcpu=v3 so the
generated code will be the same regardless of the compilation
environment.
Signed-off-by: NYonghong Song <yhs@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200219004236.2291125-1-yhs@fb.com

Daniel Xu says:

====================
Branch records are a CPU feature that can be configured to record
certain branches that are taken during code execution. This data is
particularly interesting for profile guided optimizations. perf has had
branch record support for a while but the data collection can be a bit
coarse grained.

We (Facebook) have seen in experiments that associating metadata with
branch records can improve results (after postprocessing). We generally
use bpf_probe_read_*() to get metadata out of userspace. That's why bpf
support for branch records is useful.

Aside from this particular use case, having branch data available to bpf
progs can be useful to get stack traces out of userspace applications
that omit frame pointers.

Changes in v8:
- Use globals instead of perf buffer
- Call test_perf_branches__detach() before destroying skeleton
- Fix typo in docs

Changes in v7:
- Const-ify and static-ify local var
- Documentation formatting

Changes in v6:
- Move #ifdef a little to avoid unused variable warnings on !x86
- Test negative condition in selftest (-EINVAL on improperly configured
  perf event)
- Skip positive condition selftest on setups that don't support branch
  records

Changes in v5:
- Rename bpf_perf_prog_read_branches() -> bpf_read_branch_records()
- Rename BPF_F_GET_BR_SIZE -> BPF_F_GET_BRANCH_RECORDS_SIZE
- Squash tools/ bpf.h sync into selftest commit

Changes in v4:
- Add BPF_F_GET_BR_SIZE flag
- Return -ENOENT on unsupported architectures
- Only accept initialized memory in helper
- Check buffer size is multiple of sizeof(struct perf_branch_entry)
- Use bpf skeleton in selftest
- Add commit messages
- Spelling and formatting

Changes in v3:
- Document filling unused buffer with zero
- Formatting fixes
- Rebase

Changes in v2:
- Change to a bpf helper instead of context access
- Avoid mentioning Intel specific things
====================
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

Add a selftest to test:

* default bpf_read_branch_records() behavior
* BPF_F_GET_BRANCH_RECORDS_SIZE flag behavior
* error path on non branch record perf events
* using helper to write to stack
* using helper to write to global

On host with hardware counter support:

    # ./test_progs -t perf_branches
    #27/1 perf_branches_hw:OK
    #27/2 perf_branches_no_hw:OK
    #27 perf_branches:OK
    Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED

On host without hardware counter support (VM):

    # ./test_progs -t perf_branches
    #27/1 perf_branches_hw:OK
    #27/2 perf_branches_no_hw:OK
    #27 perf_branches:OK
    Summary: 1/2 PASSED, 1 SKIPPED, 0 FAILED

Also sync tools/include/uapi/linux/bpf.h.
Signed-off-by: NDaniel Xu <dxu@dxuuu.xyz>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-3-dxu@dxuuu.xyz

Branch records are a CPU feature that can be configured to record
certain branches that are taken during code execution. This data is
particularly interesting for profile guided optimizations. perf has had
branch record support for a while but the data collection can be a bit
coarse grained.

We (Facebook) have seen in experiments that associating metadata with
branch records can improve results (after postprocessing). We generally
use bpf_probe_read_*() to get metadata out of userspace. That's why bpf
support for branch records is useful.

Aside from this particular use case, having branch data available to bpf
progs can be useful to get stack traces out of userspace applications
that omit frame pointers.
Signed-off-by: NDaniel Xu <dxu@dxuuu.xyz>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200218030432.4600-2-dxu@dxuuu.xyz

Jakub Sitnicki says:

====================
This series has been split out from "Extend SOCKMAP to store listening
sockets" [0]. I think it stands on its own, and makes the latter series
smaller, which will make the review easier, hopefully.

The essence is that we don't need to do a complicated dance in
sk_psock_restore_proto, if we agree that the contract with tcp_update_ulp
is to restore callbacks even when the socket doesn't use ULP. This is what
tcp_update_ulp currently does, and we just make use of it.

Series is accompanied by a test for a particularly tricky case of restoring
callbacks when we have both sockmap and tls callbacks configured in
sk->sk_prot.

[0] https://lore.kernel.org/bpf/20200127131057.150941-1-jakub@cloudflare.com/
====================
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

When a TCP socket gets inserted into a sockmap, its sk_prot callbacks get
replaced with tcp_bpf callbacks built from regular tcp callbacks. If TLS
gets enabled on the same socket, sk_prot callbacks get replaced once again,
this time with kTLS callbacks built from tcp_bpf callbacks.

Now, we allow removing a socket from a sockmap that has kTLS enabled. After
removal, socket remains with kTLS configured. This is where things things
get tricky.

Since the socket has a set of sk_prot callbacks that are a mix of kTLS and
tcp_bpf callbacks, we need to restore just the tcp_bpf callbacks to the
original ones. At the moment, it comes down to the the unhash operation.

We had a regression recently because tcp_bpf callbacks were not cleared in
this particular scenario of removing a kTLS socket from a sockmap. It got
fixed in commit 4da6a196 ("bpf: Sockmap/tls, during free we may call
tcp_bpf_unhash() in loop").

Add a test that triggers the regression so that we don't reintroduce it in
the future.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-4-jakub@cloudflare.com

There is no need to clear psock->sk_proto when restoring socket protocol
callbacks in sk->sk_prot. The psock is about to get detached from the sock
and eventually destroyed. At worst we will restore the protocol callbacks
and the write callback twice.

This makes reasoning about psock state easier. Once psock is initialized,
we can count on psock->sk_proto always being set.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-3-jakub@cloudflare.com

We don't need a fallback for when the socket is not using ULP.
tcp_update_ulp handles this case exactly the same as we do in
sk_psock_restore_proto. Get rid of the duplicated code.
Signed-off-by: NJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-2-jakub@cloudflare.com

bpf_perf_event_read_value() is NMI safe. Enable it for all BPF programs.
This can be used in fentry/fexit to profile BPF program and individual
kernel function with hardware counters.
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200214234146.2910011-1-songliubraving@fb.com

drivers/net/ethernet/amazon/ena/ena_com.c: In function ena_com_hash_key_allocate:
drivers/net/ethernet/amazon/ena/ena_com.c:1070:50:
 warning: variable hash_key set but not used [-Wunused-but-set-variable]

commit 6a4f7dc8 ("net: ena: rss: do not allocate key when not supported")
introduced this, but not used, so remove it.
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that the phylib module loading issue has been resolved, we can
allow this PHY driver to be built as a module.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Acked-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ursula Braun says:

====================
net/smc: patches 2020-02-17

here are patches for SMC making termination tasks more perfect.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IB event handlers schedule the port event worker for further
processing of port state changes. This patch reduces the number of
schedules to avoid duplicate processing of the same port change.
Reviewed-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

smc_lgr_terminate() and smc_lgr_terminate_sched() both result in soft
link termination, smc_lgr_terminate_sched() is scheduling a worker for
this task. Take out complexity by always using the termination worker
and getting rid of smc_lgr_terminate() completely.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The soft parameter of smc_lgr_terminate() is not used and obsolete.
Remove it.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When 2 callers call smc_lgr_terminate() at the same time
for the same lgr, one gets the lgr_lock and deletes the lgr from the
list and releases the lock. Then the second caller gets the lock and
tries to delete it again.
In smc_lgr_terminate() add a check if the link group lgr is already
deleted from the link group list and prevent to try to delete it a
second time.
And add a check if the lgr is marked as freeing, which means that a
termination is already pending.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

smc_tx_rdma_write() is called under the send_lock and should not call
smc_lgr_terminate() directly. Call smc_lgr_terminate_sched() instead
which schedules a worker.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

smc_lgr_cleanup() is called during termination processing, there is no
need to send a DELETE_LINK at that time. A DELETE_LINK should have been
sent before the termination is initiated, if needed.
And remove the extra call to wake_up(&lnk->wr_reg_wait) because
smc_llc_link_inactive() already calls the related helper function
smc_wr_wakeup_reg_wait().
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ido Schimmel says:

====================
mlxsw: Reduce dependency between bridge and router code

This patch set reduces the dependency between the bridge and the router
code in preparation for RTNL removal from the route insertion path in
mlxsw.

The motivation and solution are explained in detail in patch #3. The
main idea is that we need to stop special-casing the VXLAN devices with
regards to the reference counting of the FIDs. Otherwise, we can bump
into the situation described in patch #3, where the routing code calls
into the bridge code which calls back into the routing code. After
adding a mutex to protect router data structures to remove RTNL
dependency, this can result in an AA deadlock.

Patches #1 and #2 are preparations. They convert the FIDs to use
'refcount_t' for reference counting in order to catch over/under flows
and add extack to the bridge creation function.

Patches #3-#5 reduce the dependency between the bridge and the router
code. First, by having the VXLAN device take a reference on the FID in
patch #3 and then by removing unnecessary code following the change in
patch #3.

Patches #6-#10 adjust existing selftests and add new ones to exercise
the new code paths.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Test that when two VXLAN tunnels with conflicting configurations (i.e.,
different TTL) are enslaved to the same VLAN-aware bridge, then the
enslavement of a port to the bridge is denied.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After recent changes, the VXLAN tunnel will be offloaded regardless if
any local ports are member in the FID or not. Adjust the test to make
sure the tunnel is offloaded in this case.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>