Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices: OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
Find a file
David Vernet b66ccae01f bpf: Add libbpf logic for user-space ring buffer
Now that all of the logic is in place in the kernel to support user-space
produced ring buffers, we can add the user-space logic to libbpf. This
patch therefore adds the following public symbols to libbpf:

struct user_ring_buffer *
user_ring_buffer__new(int map_fd,
		      const struct user_ring_buffer_opts *opts);
void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
                                         __u32 size, int timeout_ms);
void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
void user_ring_buffer__discard(struct user_ring_buffer *rb,
void user_ring_buffer__free(struct user_ring_buffer *rb);

A user-space producer must first create a struct user_ring_buffer * object
with user_ring_buffer__new(), and can then reserve samples in the
ring buffer using one of the following two symbols:

void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
                                         __u32 size, int timeout_ms);

With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring
buffer will be returned if sufficient space is available in the buffer.
user_ring_buffer__reserve_blocking() provides similar semantics, but will
block for up to 'timeout_ms' in epoll_wait if there is insufficient space
in the buffer. This function has the guarantee from the kernel that it will
receive at least one event-notification per invocation to
bpf_ringbuf_drain(), provided that at least one sample is drained, and the
BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain().

Once a sample is reserved, it must either be committed to the ring buffer
with user_ring_buffer__submit(), or discarded with
user_ring_buffer__discard().

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com
2022-09-21 16:25:03 -07:00
arch bpf: Move bpf_dispatcher function out of ftrace locations 2022-09-16 22:23:20 +02:00
block
certs
crypto
Documentation bpf: Use bpf_capable() instead of CAP_SYS_ADMIN for blinding decision 2022-09-16 22:11:57 +02:00
drivers
fs
include bpf: Add bpf_user_ringbuf_drain() helper 2022-09-21 16:24:58 -07:00
init
io_uring
ipc
kernel bpf: Add bpf_user_ringbuf_drain() helper 2022-09-21 16:24:58 -07:00
lib
LICENSES
mm
net bpf: Move nf_conn extern declarations to filter.h 2022-09-20 14:41:35 -07:00
samples samples/bpf: Replace blk_account_io_done() with __blk_account_io_done() 2022-09-20 17:25:59 -07:00
scripts
security
sound
tools bpf: Add libbpf logic for user-space ring buffer 2022-09-21 16:25:03 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.