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Dave Marchevsky 1512217c47 bpf: Support refcounted local kptrs in existing semantics
A local kptr is considered 'refcounted' when it is of a type that has a
bpf_refcount field. When such a kptr is created, its refcount should be
initialized to 1; when destroyed, the object should be free'd only if a
refcount decr results in 0 refcount.

Existing logic always frees the underlying memory when destroying a
local kptr, and 0-initializes all btf_record fields. This patch adds
checks for "is local kptr refcounted?" and new logic for that case in
the appropriate places.

This patch focuses on changing existing semantics and thus conspicuously
does _not_ provide a way for BPF programs in increment refcount. That
follows later in the series.

__bpf_obj_drop_impl is modified to do the right thing when it sees a
refcounted type. Container types for graph nodes (list, tree, stashed in
map) are migrated to use __bpf_obj_drop_impl as a destructor for their
nodes instead of each having custom destruction code in their _free
paths. Now that "drop" isn't a synonym for "free" when the type is
refcounted it makes sense to centralize this logic.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-15 17:36:49 -07:00
arch bpf: Support 64-bit pointers to kfuncs 2023-04-13 21:36:41 -07:00
block block: don't set GD_NEED_PART_SCAN if scan partition failed 2023-04-06 20:41:53 -06:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto asymmetric_keys: log on fatal failures in PE/pkcs7 2023-03-21 16:23:56 +00:00
Documentation bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
drivers bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-13 16:04:28 -07:00
include bpf: Support refcounted local kptrs in existing semantics 2023-04-15 17:36:49 -07:00
init bootconfig: Change message if no bootconfig with CONFIG_BOOT_CONFIG_FORCE=y 2023-03-22 22:21:43 +09:00
io_uring Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-13 16:04:28 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel bpf: Support refcounted local kptrs in existing semantics 2023-04-15 17:36:49 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-13 16:04:28 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
net bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
rust Rust fixes for 6.3-rc1 2023-03-03 14:51:15 -08:00
samples samples/bpf: sampleip: Replace PAGE_OFFSET with _text address 2023-04-13 21:57:11 -07:00
scripts bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-03-24 10:10:20 -07:00
sound ALSA: hda/hdmi: Preserve the previous PCM device upon re-enablement 2023-04-01 18:05:48 +02:00
tools bpf: Introduce opaque bpf_refcount struct and add btf_record plumbing 2023-04-15 17:36:49 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE platform dependent 2023-03-31 11:19:05 -04:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore kbuild: rpm-pkg: move source components to rpmbuild/SOURCES 2023-03-16 22:45:56 +09:00
.mailmap mailmap: add an entry for Leonard Crestez 2023-03-28 15:24:32 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-13 16:04:28 -07:00
Makefile Linux 6.3-rc6 2023-04-09 11:15:57 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.