Linux kernel source tree
Go to file
Kairui Song 0fcf8ef4fd mm, swap: tidy up swap device and cluster info helpers
swp_swap_info is the most commonly used helper for retrieving swap info. 
It has an internal check that may lead to a NULL return value, but almost
none of its caller checks the return value, making the internal check
pointless.  In fact, most of these callers already ensured the entry is
valid and never expect a NULL value.

Tidy this up and improve the function names.  If the caller can make sure
the swap entry/type is valid and the device is pinned, use the new
introduced __swap_entry_to_info/__swap_type_to_info instead.  They have
more debug sanity checks and lower overhead as they are inlined.

Callers that may expect a NULL value should use
swap_entry_to_info/swap_type_to_info instead.

No feature change.  The rearranged codes should have had no effect, or
they should have been hitting NULL de-ref bugs already.  Only some new
sanity checks are added so potential issues may show up in debug build.

The new helpers will be frequently used with swap table later when working
with swap cache folios.  A locked swap cache folio ensures the entries are
valid and stable so these helpers are very helpful.

Link: https://lkml.kernel.org/r/20250916160100.31545-8-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Chris Li <chrisl@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: Chris Li <chrisl@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: kernel test robot <oliver.sang@intel.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:23 -07:00
arch arm64: stop calling page_address() in free_pages() 2025-09-21 14:22:18 -07:00
block block: use largest_zero_folio in __blkdev_issue_zero_pages() 2025-09-13 16:54:54 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: remove nth_page() usage within SG entry 2025-09-21 14:22:09 -07:00
Documentation docs/mm: add document for swap table 2025-09-21 14:22:22 -07:00
drivers virtio_balloon: stop calling page_address() in free_pages() 2025-09-21 14:22:18 -07:00
fs mm/hwpoison: decouple hwpoison_filter from mm/memory-failure.c 2025-09-21 14:22:21 -07:00
include mm, swap: tidy up swap device and cluster info helpers 2025-09-21 14:22:23 -07:00
init init/main.c: fix boot time tracing crash 2025-09-03 17:10:36 -07:00
io_uring io_uring/zcrx: remove nth_page() usage within folio 2025-09-21 14:22:05 -07:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel dma-remap: drop nth_page() in dma_common_contiguous_remap() 2025-09-21 14:22:06 -07:00
lib kasan: introduce ARCH_DEFER_KASAN and unify static key across modes 2025-09-21 14:21:58 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm, swap: tidy up swap device and cluster info helpers 2025-09-21 14:22:23 -07:00
net net: ipv4: fix regression in local-broadcast routes 2025-08-28 10:52:30 +02:00
rust rust: maple_tree: add MapleTreeAlloc 2025-09-21 14:22:19 -07:00
samples samples/damon/mtier: avoid starting DAMON before initialization 2025-09-13 13:05:38 -07:00
scripts kasan: fix GCC mem-intrinsic prefix with sw tags 2025-08-27 22:45:43 -07:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/hdmi: Add pin fix for another HP EliteDesk 800 G4 model 2025-09-01 13:51:57 +02:00
tools selftests/mm: split_huge_page_test: cleanups for split_pte_mapped_thp test 2025-09-21 14:22:20 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.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: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap .mailmap: add entry for Easwar Hariharan 2025-08-19 16:35:55 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -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: retire Boris from TLS maintainers 2025-08-26 17:36:01 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS docs/mm: add document for swap table 2025-09-21 14:22:22 -07:00
Makefile Linux 6.17-rc4 2025-08-31 15:33:07 -07:00
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.