mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-12-28 10:15:32 -05:00
ae38eb2105
Swap cache lookup only increases the reference count of the returned folio. That's not enough to ensure a folio is stable in the swap cache, so the folio could be removed from the swap cache at any time. The caller should always lock and check the folio before using it. We have just documented this in kerneldoc, now introduce a helper for swap cache folio verification with proper sanity checks. Also, sanitize a few current users to use this convention and the new helper for easier debugging. They were not having observable problems yet, only trivial issues like wasted CPU cycles on swapoff or reclaiming. They would fail in some other way, but it is still better to always follow this convention to make things robust and make later commits easier to do. Link: https://lkml.kernel.org/r/20250916160100.31545-6-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Chris Li <chrisl@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Chris Li <chrisl@kernel.org> Reviewed-by: Barry Song <baohua@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: 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>
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.