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Paolo Abeni 9db5b3cec4 mptcp: borrow forward memory from subflow
In the MPTCP receive path, we release the subflow allocated fwd
memory just to allocate it again shortly after for the msk.

That could increases the failures chances, especially when we will
add backlog processing, with other actions could consume the just
released memory before the msk socket has a chance to do the
rcv allocation.

Replace the skb_orphan() call with an open-coded variant that
explicitly borrows, the fwd memory from the subflow socket instead
of releasing it.

The borrowed memory does not have PAGE_SIZE granularity; rounding to
the page size will make the fwd allocated memory higher than what is
strictly required and could make the incoming subflow fwd mem
consistently negative. Instead, keep track of the accumulated frag and
borrow the full page at subflow close time.

This allow removing the last drop in the TCP to MPTCP transition and
the associated, now unused, MIB.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-12-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Documentation net/mlx5: implement swp_l4_csum_mode via devlink params 2025-11-20 19:01:22 -08:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-11-20 09:13:26 -08:00
block vfs-6.18-rc7.fixes 2025-11-17 09:11:27 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto net: Convert proto_ops bind() callbacks to use sockaddr_unsized 2025-11-04 19:10:32 -08:00
drivers ipvlan: fix sparse warning about __be32 -> u32 2025-11-24 19:48:49 -08:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-11-20 09:13:26 -08:00
include net: factor-out _sk_charge() helper 2025-11-24 19:49:40 -08:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rsrc: don't use blk_rq_nr_phys_segments() as number of bvecs 2025-11-12 08:25:33 -07:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-11-20 09:13:26 -08:00
lib lib/test_kho: check if KHO is enabled 2025-11-15 10:52:01 -08:00
mm memblock: fix memblock_estimated_nr_free_pages() for soft-reserved memory 2025-11-19 08:27:05 -08:00
net mptcp: borrow forward memory from subflow 2025-11-24 19:49:42 -08:00
rust rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags 2025-11-10 08:37:06 +08:00
samples net: Convert proto_ops connect() callbacks to use sockaddr_unsized 2025-11-04 19:10:32 -08:00
scripts Rust fixes for v6.18 (2nd) 2025-11-14 15:36:15 -08:00
security landlock: fix splats from iput() after it started calling might_sleep() 2025-11-12 10:47:42 +01:00
sound ALSA: usb-audio: Add native DSD quirks for PureAudio DAC series 2025-11-14 14:19:47 +01:00
tools selftests: af_unix: don't use SKIP for expected failures 2025-11-24 19:07:51 -08:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap soc: fixes for 6.18, part 3 2025-11-19 09:36:04 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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 MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-11-20 09:13:26 -08:00
Makefile Linux 6.18-rc6 2025-11-16 14:25:38 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.