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Kuan-Wei Chiu f1e2ca801c lib/base64: add support for multiple variants
Patch series " lib/base64: add generic encoder/decoder, migrate users", v5.

This series introduces a generic Base64 encoder/decoder to the kernel
library, eliminating duplicated implementations and delivering significant
performance improvements.

The Base64 API has been extended to support multiple variants (Standard,
URL-safe, and IMAP) as defined in RFC 4648 and RFC 3501.  The API now
takes a variant parameter and an option to control padding.  As part of
this series, users are migrated to the new interface while preserving
their specific formats: fscrypt now uses BASE64_URLSAFE, Ceph uses
BASE64_IMAP, and NVMe is updated to BASE64_STD.

On the encoder side, the implementation processes input in 3-byte blocks,
mapping 24 bits directly to 4 output symbols.  This avoids bit-by-bit
streaming and reduces loop overhead, achieving about a 2.7x speedup
compared to previous implementations.

On the decoder side, replace strchr() lookups with per-variant reverse
tables and process input in 4-character groups.  Each group is mapped to
numeric values and combined into 3 bytes.  Padded and unpadded forms are
validated explicitly, rejecting invalid '=' usage and enforcing tail
rules.  This improves throughput by ~43-52x.


This patch (of 6):

Extend the base64 API to support multiple variants (standard, URL-safe,
and IMAP) as defined in RFC 4648 and RFC 3501.  The API now takes a
variant parameter and an option to control padding.  Update NVMe auth code
to use the new interface with BASE64_STD.

Link: https://lkml.kernel.org/r/20251114055829.87814-1-409411716@gms.tku.edu.tw
Link: https://lkml.kernel.org/r/20251114060045.88792-1-409411716@gms.tku.edu.tw
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Co-developed-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: David Laight <david.laight.linux@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-20 14:03:43 -08:00
arch lib: mul_u64_u64_div_u64(): optimise multiply on 32bit x86 2025-11-20 14:03:42 -08:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation sys_info: add a default kernel sys_info mask 2025-11-20 14:03:43 -08:00
drivers lib/base64: add support for multiple variants 2025-11-20 14:03:43 -08:00
fs fs/proc/page: remove unused KPMBITS 2025-11-20 14:03:42 -08:00
include lib/base64: add support for multiple variants 2025-11-20 14:03:43 -08:00
init init/main.c: wrap long kernel cmdline when printing to logs 2025-11-12 10:00:16 -08:00
io_uring io_uring: fix regbuf vector size truncation 2025-11-07 17:17:13 -07:00
ipc ipc: create_ipc_ns: drop mqueue mount on sysctl setup failure 2025-11-12 10:00:15 -08:00
kernel watchdog: add sys_info sysctls to dump sys info on system lockup 2025-11-20 14:03:43 -08:00
lib lib/base64: add support for multiple variants 2025-11-20 14:03:43 -08:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab fix for 6.18-rc5 2025-11-07 08:01:58 -08:00
net Including fixes from bluetooth and wireless. 2025-11-06 08:52:30 -08:00
rust uaccess: decouple INLINE_COPY_FROM_USER and CONFIG_RUST 2025-11-12 10:00:16 -08:00
samples samples: fix coding style issues in Kconfig 2025-11-11 16:48:28 -08:00
scripts scripts/gdb/symbols: make BPF debug info available to GDB 2025-11-20 14:03:42 -08:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ASoC: Fixes for v6.18 2025-10-30 13:08:08 +01:00
tools hung_task: panic when there are more than N hung tasks at the same time 2025-11-12 10:00:14 -08:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.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 mailmap: add entry for Hao Ge 2025-11-12 10:00:17 -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 CREDITS: update Martin's information 2025-11-12 10:00:14 -08:00
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 MAINTAINERS: remove Gustavo from sync framework 2025-11-20 14:03:43 -08:00
Makefile Linux 6.18-rc5 2025-11-09 15:10:19 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.