mirror of
https://github.com/torvalds/linux.git
synced 2026-07-30 11:11:26 +02:00
Linux kernel source tree
bdd0d69a32
Patch series "Improve folio split related functions", v4. This patchset improves several folio split related functions to avoid future misuse. The changes are: 1. Consolidated folio splittable checks by moving truncated folio check, huge zero folio check, and writeback folio check into folio_split_supported(). Changed the function return type. Renamed it to folio_check_splittable() for clarification. 2. Replaced can_split_folio() with open coded folio_expected_ref_count() and folio_ref_count() and introduced folio_cache_ref_count(). 3. Changed min_order_for_split() to always return an order. 4. Fixed folio split stats counting. Motivation ========== This is based on Wei's observation[1] and solves several potential issues: 1. Dereferencing NULL folio->mapping in try_folio_split_to_order() if it is called on truncated folios. 2. Not handling of negative return value of min_order_for_split() in mm/memory-failure.c There is no bug in the current code. This patch (of 4): folio_split_supported() used in try_folio_split_to_order() requires folio->mapping to be non NULL, but current try_folio_split_to_order() does not check it. There is no issue in the current code, since try_folio_split_to_order() is only used in truncate_inode_partial_folio(), where folio->mapping is not NULL. To prevent future misuse, move folio->mapping NULL check (i.e., folio is truncated) into folio_split_supported(). Since folio->mapping NULL check returns -EBUSY and folio_split_supported() == false means -EINVAL, change folio_split_supported() return type from bool to int and return error numbers accordingly. Rename folio_split_supported() to folio_check_splittable() to match the return type change. While at it, move is_huge_zero_folio() check and folio_test_writeback() check into folio_check_splittable() and add kernel-doc. Remove all warnings inside folio_check_splittable() and give warnings in __folio_split() instead, so that bool warns parameter can be removed. Link: https://lkml.kernel.org/r/20251126210618.1971206-1-ziy@nvidia.com Link: https://lkml.kernel.org/r/20251126210618.1971206-2-ziy@nvidia.com Signed-off-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: Balbir Singh <balbirs@nvidia.com> Acked-by: David Hildenbrand (Red Hat) <david@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Nico Pache <npache@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.