* [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd
@ 2020-12-14 11:38 Brendan Jackman
2020-12-14 20:46 ` Daniel Borkmann
0 siblings, 1 reply; 5+ messages in thread
From: Brendan Jackman @ 2020-12-14 11:38 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, KP Singh,
Florent Revest, linux-kernel, Brendan Jackman
This provides a convenient perf ringbuf -> libbpf ringbuf migration
path for users of external polling systems. It is analogous to
perf_buffer__epoll_fd.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
Difference from v1: Added entry to libbpf.map.
tools/lib/bpf/libbpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/ringbuf.c | 6 ++++++
3 files changed, 8 insertions(+)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 6909ee81113a..cde07f64771e 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -536,6 +536,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
ring_buffer_sample_fn sample_cb, void *ctx);
LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__epoll_fd(struct ring_buffer *rb);
/* Perf buffer APIs */
struct perf_buffer;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7c4126542e2b..7be850271be6 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -348,4 +348,5 @@ LIBBPF_0.3.0 {
btf__new_split;
xsk_setup_xdp_prog;
xsk_socket__update_xskmap;
+ ring_buffer__epoll_fd;
} LIBBPF_0.2.0;
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 5c6522c89af1..45a36648b403 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -282,3 +282,9 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
}
return cnt < 0 ? -errno : res;
}
+
+/* Get an fd that can be used to sleep until data is available in the ring(s) */
+int ring_buffer__epoll_fd(struct ring_buffer *rb)
+{
+ return rb->epoll_fd;
+}
base-commit: b4fe9fec51ef48011f11c2da4099f0b530449c92
--
2.29.2.576.ga3fc446d84-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd
2020-12-14 11:38 [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd Brendan Jackman
@ 2020-12-14 20:46 ` Daniel Borkmann
2020-12-15 10:25 ` Brendan Jackman
0 siblings, 1 reply; 5+ messages in thread
From: Daniel Borkmann @ 2020-12-14 20:46 UTC (permalink / raw)
To: Brendan Jackman, bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, KP Singh, Florent Revest,
linux-kernel
On 12/14/20 12:38 PM, Brendan Jackman wrote:
> This provides a convenient perf ringbuf -> libbpf ringbuf migration
> path for users of external polling systems. It is analogous to
> perf_buffer__epoll_fd.
>
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
> Difference from v1: Added entry to libbpf.map.
>
> tools/lib/bpf/libbpf.h | 1 +
> tools/lib/bpf/libbpf.map | 1 +
> tools/lib/bpf/ringbuf.c | 6 ++++++
> 3 files changed, 8 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 6909ee81113a..cde07f64771e 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -536,6 +536,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
> ring_buffer_sample_fn sample_cb, void *ctx);
> LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
> LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
> +LIBBPF_API int ring_buffer__epoll_fd(struct ring_buffer *rb);
>
> /* Perf buffer APIs */
> struct perf_buffer;
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 7c4126542e2b..7be850271be6 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -348,4 +348,5 @@ LIBBPF_0.3.0 {
> btf__new_split;
> xsk_setup_xdp_prog;
> xsk_socket__update_xskmap;
> + ring_buffer__epoll_fd;
Fyi, this had a whitespace issue, Andrii fixed it up while applying.
> } LIBBPF_0.2.0;
> diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
> index 5c6522c89af1..45a36648b403 100644
> --- a/tools/lib/bpf/ringbuf.c
> +++ b/tools/lib/bpf/ringbuf.c
> @@ -282,3 +282,9 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
> }
> return cnt < 0 ? -errno : res;
> }
> +
> +/* Get an fd that can be used to sleep until data is available in the ring(s) */
> +int ring_buffer__epoll_fd(struct ring_buffer *rb)
> +{
> + return rb->epoll_fd;
> +}
>
> base-commit: b4fe9fec51ef48011f11c2da4099f0b530449c92
> --
> 2.29.2.576.ga3fc446d84-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd
2020-12-14 20:46 ` Daniel Borkmann
@ 2020-12-15 10:25 ` Brendan Jackman
0 siblings, 0 replies; 5+ messages in thread
From: Brendan Jackman @ 2020-12-15 10:25 UTC (permalink / raw)
To: Daniel Borkmann
Cc: bpf, Alexei Starovoitov, Andrii Nakryiko, KP Singh, Florent Revest, LKML
On Mon, 14 Dec 2020 at 21:46, Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> On 12/14/20 12:38 PM, Brendan Jackman wrote:
[...]
> > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> > index 7c4126542e2b..7be850271be6 100644
> > --- a/tools/lib/bpf/libbpf.map
> > +++ b/tools/lib/bpf/libbpf.map
> > @@ -348,4 +348,5 @@ LIBBPF_0.3.0 {
> > btf__new_split;
> > xsk_setup_xdp_prog;
> > xsk_socket__update_xskmap;
> > + ring_buffer__epoll_fd;
>
> Fyi, this had a whitespace issue, Andrii fixed it up while applying.
Sorry about that.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH bpf-next v4 00/11] Atomics for eBPF
@ 2020-12-15 12:18 Brendan Jackman
2020-12-15 12:18 ` [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd Brendan Jackman
0 siblings, 1 reply; 5+ messages in thread
From: Brendan Jackman @ 2020-12-15 12:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, KP Singh,
Florent Revest, linux-kernel, Brendan Jackman
Status of the patches
=====================
Thanks for the reviews!
There's one review comment from John which I haven't resolved [3].
He pointed out that we could make the verifier a bit smarter about
propagating register bounds. I don't have a clear picture of how
useful it would be but IIUC it would be quite simple (see my reply to
the linked mail with a proposed implementation).
Differences from v4->v5 [1]:
* Fixed bogus type casts in interpreter that led to warnings from
the 0day robot.
* Dropped feature-detection for Clang per Andrii's suggestion in [4].
The selftests will now fail to build unless you have llvm-project
commit 286daafd6512. The ENABLE_ATOMICS_TEST macro is still needed
to support the no_alu32 tests.
* Carried some Acks from John and Yonghong.
* Dropped confusing usage of __atomic_exchange from prog_test in
favour of __sync_lock_test_and_set.
* [Really] got rid of all the forest of instruction macros
(BPF_ATOMIC_FETCH_ADD and friends); now there's just BPF_ATOMIC_OP
to define all the instructions as we use them in the verifier
tests. This makes the atomic ops less special in that API, and I
don't think the resulting usage is actually any harder to read.
Differences from v3->v4 [1]:
* Added one Ack from Yonghong. He acked some other patches but those
have now changed non-trivally so I didn't add those acks.
* Fixups to commit messages.
* Fixed disassembly and comments: first arg to atomic_fetch_* is a
pointer.
* Improved prog_test efficiency. BPF progs are now all loaded in a
single call, then the skeleton is re-used for each subtest.
* Dropped use of tools/build/feature in favour of a one-liner in the
Makefile.
* Dropped the commit that created an emit_neg helper in the x86
JIT. It's not used any more (it wasn't used in v3 either).
* Combined all the different filter.h macros (used to be
BPF_ATOMIC_ADD, BPF_ATOMIC_FETCH_ADD, BPF_ATOMIC_AND, etc) into
just BPF_ATOMIC32 and BPF_ATOMIC64.
* Removed some references to BPF_STX_XADD from tools/, samples/ and
lib/ that I missed before.
Differences from v2->v3 [1]:
* More minor fixes and naming/comment changes
* Dropped atomic subtract: compilers can implement this by preceding
an atomic add with a NEG instruction (which is what the x86 JIT did
under the hood anyway).
* Dropped the use of -mcpu=v4 in the Clang BPF command-line; there is
no longer an architecture version bump. Instead a feature test is
added to Kbuild - it builds a source file to check if Clang
supports BPF atomics.
* Fixed the prog_test so it no longer breaks
test_progs-no_alu32. This requires some ifdef acrobatics to avoid
complicating the prog_tests model where the same userspace code
exercises both the normal and no_alu32 BPF test objects, using the
same skeleton header.
Differences from v1->v2 [1]:
* Fixed mistakes in the netronome driver
* Addd sub, add, or, xor operations
* The above led to some refactors to keep things readable. (Maybe I
should have just waited until I'd implemented these before starting
the review...)
* Replaced BPF_[CMP]SET | BPF_FETCH with just BPF_[CMP]XCHG, which
include the BPF_FETCH flag
* Added a bit of documentation. Suggestions welcome for more places
to dump this info...
The prog_test that's added depends on Clang/LLVM features added by
Yonghong in commit 286daafd6512 (was
https://reviews.llvm.org/D72184).
This only includes a JIT implementation for x86_64 - I don't plan to
implement JIT support myself for other architectures.
Operations
==========
This patchset adds atomic operations to the eBPF instruction set. The
use-case that motivated this work was a trivial and efficient way to
generate globally-unique cookies in BPF progs, but I think it's
obvious that these features are pretty widely applicable. The
instructions that are added here can be summarised with this list of
kernel operations:
* atomic[64]_[fetch_]add
* atomic[64]_[fetch_]and
* atomic[64]_[fetch_]or
* atomic[64]_xchg
* atomic[64]_cmpxchg
The following are left out of scope for this effort:
* 16 and 8 bit operations
* Explicit memory barriers
Encoding
========
I originally planned to add new values for bpf_insn.opcode. This was
rather unpleasant: the opcode space has holes in it but no entire
instruction classes[2]. Yonghong Song had a better idea: use the
immediate field of the existing STX XADD instruction to encode the
operation. This works nicely, without breaking existing programs,
because the immediate field is currently reserved-must-be-zero, and
extra-nicely because BPF_ADD happens to be zero.
Note that this of course makes immediate-source atomic operations
impossible. It's hard to imagine a measurable speedup from such
instructions, and if it existed it would certainly not benefit x86,
which has no support for them.
The BPF_OP opcode fields are re-used in the immediate, and an
additional flag BPF_FETCH is used to mark instructions that should
fetch a pre-modification value from memory.
So, BPF_XADD is now called BPF_ATOMIC (the old name is kept to avoid
breaking userspace builds), and where we previously had .imm = 0, we
now have .imm = BPF_ADD (which is 0).
Operands
========
Reg-source eBPF instructions only have two operands, while these
atomic operations have up to four. To avoid needing to encode
additional operands, then:
- One of the input registers is re-used as an output register
(e.g. atomic_fetch_add both reads from and writes to the source
register).
- Where necessary (i.e. for cmpxchg) , R0 is "hard-coded" as one of
the operands.
This approach also allows the new eBPF instructions to map directly
to single x86 instructions.
[1] Previous iterations:
v1: https://lore.kernel.org/bpf/20201123173202.1335708-1-jackmanb@google.com/
v2: https://lore.kernel.org/bpf/20201127175738.1085417-1-jackmanb@google.com/
v3: https://lore.kernel.org/bpf/X8kN7NA7bJC7aLQI@google.com/
v4: https://lore.kernel.org/bpf/20201207160734.2345502-1-jackmanb@google.com/
[2] Visualisation of eBPF opcode space:
https://gist.github.com/bjackman/00fdad2d5dfff601c1918bc29b16e778
[3] Comment from John about propagating bounds in verifier:
https://lore.kernel.org/bpf/5fcf0fbcc8aa8_9ab320853@john-XPS-13-9370.notmuch/
[4] Mail from Andrii about not supporting old Clang in selftests:
https://lore.kernel.org/bpf/CAEf4BzYBddPaEzRUs=jaWSo5kbf=LZdb7geAUVj85GxLQztuAQ@mail.gmail.com/
Brendan Jackman (11):
bpf: x86: Factor out emission of ModR/M for *(reg + off)
bpf: x86: Factor out emission of REX byte
bpf: x86: Factor out a lookup table for some ALU opcodes
bpf: Rename BPF_XADD and prepare to encode other atomics in .imm
bpf: Move BPF_STX reserved field check into BPF_STX verifier code
bpf: Add BPF_FETCH field / create atomic_fetch_add instruction
bpf: Add instructions for atomic_[cmp]xchg
bpf: Pull out a macro for interpreting atomic ALU operations
bpf: Add bitwise atomic instructions
bpf: Add tests for new BPF atomic operations
bpf: Document new atomic instructions
Documentation/networking/filter.rst | 56 +++-
arch/arm/net/bpf_jit_32.c | 7 +-
arch/arm64/net/bpf_jit_comp.c | 16 +-
arch/mips/net/ebpf_jit.c | 11 +-
arch/powerpc/net/bpf_jit_comp64.c | 25 +-
arch/riscv/net/bpf_jit_comp32.c | 20 +-
arch/riscv/net/bpf_jit_comp64.c | 16 +-
arch/s390/net/bpf_jit_comp.c | 27 +-
arch/sparc/net/bpf_jit_comp_64.c | 17 +-
arch/x86/net/bpf_jit_comp.c | 217 ++++++++++-----
arch/x86/net/bpf_jit_comp32.c | 6 +-
drivers/net/ethernet/netronome/nfp/bpf/jit.c | 14 +-
drivers/net/ethernet/netronome/nfp/bpf/main.h | 4 +-
.../net/ethernet/netronome/nfp/bpf/verifier.c | 15 +-
include/linux/filter.h | 25 +-
include/uapi/linux/bpf.h | 10 +-
kernel/bpf/core.c | 67 ++++-
kernel/bpf/disasm.c | 43 ++-
kernel/bpf/verifier.c | 75 ++++--
lib/test_bpf.c | 14 +-
samples/bpf/bpf_insn.h | 4 +-
samples/bpf/cookie_uid_helper_example.c | 8 +-
samples/bpf/sock_example.c | 2 +-
samples/bpf/test_cgrp2_attach.c | 5 +-
tools/include/linux/filter.h | 24 +-
tools/include/uapi/linux/bpf.h | 10 +-
tools/testing/selftests/bpf/Makefile | 2 +
.../selftests/bpf/prog_tests/atomics.c | 246 ++++++++++++++++++
.../bpf/prog_tests/cgroup_attach_multi.c | 4 +-
tools/testing/selftests/bpf/progs/atomics.c | 154 +++++++++++
.../selftests/bpf/test_cgroup_storage.c | 2 +-
.../selftests/bpf/verifier/atomic_and.c | 77 ++++++
.../selftests/bpf/verifier/atomic_cmpxchg.c | 96 +++++++
.../selftests/bpf/verifier/atomic_fetch_add.c | 106 ++++++++
.../selftests/bpf/verifier/atomic_or.c | 77 ++++++
.../selftests/bpf/verifier/atomic_xchg.c | 46 ++++
.../selftests/bpf/verifier/atomic_xor.c | 77 ++++++
tools/testing/selftests/bpf/verifier/ctx.c | 7 +-
.../bpf/verifier/direct_packet_access.c | 4 +-
.../testing/selftests/bpf/verifier/leak_ptr.c | 10 +-
.../selftests/bpf/verifier/meta_access.c | 4 +-
tools/testing/selftests/bpf/verifier/unpriv.c | 3 +-
.../bpf/verifier/value_illegal_alu.c | 2 +-
tools/testing/selftests/bpf/verifier/xadd.c | 18 +-
44 files changed, 1461 insertions(+), 212 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/atomics.c
create mode 100644 tools/testing/selftests/bpf/progs/atomics.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_and.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_fetch_add.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_or.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_xchg.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_xor.c
base-commit: 0e12c0271887f1b00b79b7612c1d4f0d3d34e8a8
--
2.29.2.684.gfbc64c5ab5-goog
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd
2020-12-15 12:18 [PATCH bpf-next v4 00/11] Atomics for eBPF Brendan Jackman
@ 2020-12-15 12:18 ` Brendan Jackman
2020-12-15 18:35 ` Andrii Nakryiko
0 siblings, 1 reply; 5+ messages in thread
From: Brendan Jackman @ 2020-12-15 12:18 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, KP Singh,
Florent Revest, linux-kernel, Brendan Jackman
This provides a convenient perf ringbuf -> libbpf ringbuf migration
path for users of external polling systems. It is analogous to
perf_buffer__epoll_fd.
Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
Difference from v1: Added entry to libbpf.map.
tools/lib/bpf/libbpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/ringbuf.c | 6 ++++++
3 files changed, 8 insertions(+)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 6909ee81113a..cde07f64771e 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -536,6 +536,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
ring_buffer_sample_fn sample_cb, void *ctx);
LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__epoll_fd(struct ring_buffer *rb);
/* Perf buffer APIs */
struct perf_buffer;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7c4126542e2b..7be850271be6 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -348,4 +348,5 @@ LIBBPF_0.3.0 {
btf__new_split;
xsk_setup_xdp_prog;
xsk_socket__update_xskmap;
+ ring_buffer__epoll_fd;
} LIBBPF_0.2.0;
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 5c6522c89af1..45a36648b403 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -282,3 +282,9 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
}
return cnt < 0 ? -errno : res;
}
+
+/* Get an fd that can be used to sleep until data is available in the ring(s) */
+int ring_buffer__epoll_fd(struct ring_buffer *rb)
+{
+ return rb->epoll_fd;
+}
base-commit: b4fe9fec51ef48011f11c2da4099f0b530449c92
--
2.29.2.576.ga3fc446d84-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd
2020-12-15 12:18 ` [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd Brendan Jackman
@ 2020-12-15 18:35 ` Andrii Nakryiko
0 siblings, 0 replies; 5+ messages in thread
From: Andrii Nakryiko @ 2020-12-15 18:35 UTC (permalink / raw)
To: Brendan Jackman
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, KP Singh,
Florent Revest, open list
On Tue, Dec 15, 2020 at 4:18 AM Brendan Jackman <jackmanb@google.com> wrote:
>
> This provides a convenient perf ringbuf -> libbpf ringbuf migration
> path for users of external polling systems. It is analogous to
> perf_buffer__epoll_fd.
>
> Signed-off-by: Brendan Jackman <jackmanb@google.com>
> ---
> Difference from v1: Added entry to libbpf.map.
>
I've already applied this yesterday as a4d2a7ad8683 ("libbpf: Expose
libbpf ring_buffer epoll_fd"), no need to re-send.
> tools/lib/bpf/libbpf.h | 1 +
> tools/lib/bpf/libbpf.map | 1 +
> tools/lib/bpf/ringbuf.c | 6 ++++++
> 3 files changed, 8 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 6909ee81113a..cde07f64771e 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -536,6 +536,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
> ring_buffer_sample_fn sample_cb, void *ctx);
> LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
> LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
> +LIBBPF_API int ring_buffer__epoll_fd(struct ring_buffer *rb);
>
> /* Perf buffer APIs */
> struct perf_buffer;
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index 7c4126542e2b..7be850271be6 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -348,4 +348,5 @@ LIBBPF_0.3.0 {
> btf__new_split;
> xsk_setup_xdp_prog;
> xsk_socket__update_xskmap;
> + ring_buffer__epoll_fd;
I've put this in the alphabetic order...
> } LIBBPF_0.2.0;
> diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
> index 5c6522c89af1..45a36648b403 100644
> --- a/tools/lib/bpf/ringbuf.c
> +++ b/tools/lib/bpf/ringbuf.c
> @@ -282,3 +282,9 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
> }
> return cnt < 0 ? -errno : res;
> }
> +
> +/* Get an fd that can be used to sleep until data is available in the ring(s) */
> +int ring_buffer__epoll_fd(struct ring_buffer *rb)
... and also added const here, btw.
> +{
> + return rb->epoll_fd;
> +}
>
> base-commit: b4fe9fec51ef48011f11c2da4099f0b530449c92
> --
> 2.29.2.576.ga3fc446d84-goog
>
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2020-12-14 11:38 [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd Brendan Jackman
2020-12-14 20:46 ` Daniel Borkmann
2020-12-15 10:25 ` Brendan Jackman
2020-12-15 12:18 [PATCH bpf-next v4 00/11] Atomics for eBPF Brendan Jackman
2020-12-15 12:18 ` [PATCH bpf-next v2] libbpf: Expose libbpf ringbufer epoll_fd Brendan Jackman
2020-12-15 18:35 ` Andrii Nakryiko
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