The patch titled Subject: buffer: improve bdev_getblk documentation has been added to the -mm mm-unstable branch. Its filename is buffer-improve-bdev_getblk-documentation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/buffer-improve-bdev_getblk-documentation.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: buffer: improve bdev_getblk documentation Date: Tue, 16 Apr 2024 04:17:51 +0100 Add some more information about the state of the buffer_head returned. Link: https://lkml.kernel.org/r/20240416031754.4076917-8-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/buffer.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/fs/buffer.c~buffer-improve-bdev_getblk-documentation +++ a/fs/buffer.c @@ -1424,6 +1424,11 @@ EXPORT_SYMBOL(__find_get_block); * @size: The size of buffer_heads for this @bdev. * @gfp: The memory allocation flags to use. * + * The returned buffer head has its reference count incremented, but is + * not locked. The caller should call brelse() when it has finished + * with the buffer. The buffer may not be uptodate. If needed, the + * caller can bring it uptodate either by reading it or overwriting it. + * * Return: The buffer head, or NULL if memory could not be allocated. */ struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, _ Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are mm-always-initialise-folio-_deferred_list.patch mm-create-folio_flag_false-and-folio_type_ops-macros.patch mm-remove-folio_prep_large_rmappable.patch mm-support-page_mapcount-on-page_has_type-pages.patch mm-turn-folio_test_hugetlb-into-a-pagetype.patch mm-turn-folio_test_hugetlb-into-a-pagetype-fix.patch mm-remove-a-call-to-compound_head-from-is_page_hwpoison.patch mm-free-up-pg_slab.patch mm-free-up-pg_slab-fix.patch mm-improve-dumping-of-mapcount-and-page_type.patch hugetlb-remove-mention-of-destructors.patch sh-remove-use-of-pg_arch_1-on-individual-pages.patch xtensa-remove-uses-of-pg_arch_1-on-individual-pages.patch mm-make-page_ext_get-take-a-const-argument.patch mm-make-folio_test_idle-and-folio_test_young-take-a-const-argument.patch mm-make-is_free_buddy_page-take-a-const-argument.patch mm-make-page_mapped-take-a-const-argument.patch mm-convert-arch_clear_hugepage_flags-to-take-a-folio.patch mm-convert-arch_clear_hugepage_flags-to-take-a-folio-fix.patch slub-remove-use-of-page-flags.patch remove-references-to-page-flags-in-documentation.patch proc-rewrite-stable_page_flags.patch proc-rewrite-stable_page_flags-fix.patch proc-rewrite-stable_page_flags-fix-2.patch sparc-use-is_huge_zero_pmd.patch mm-add-is_huge_zero_folio.patch mm-add-pmd_folio.patch mm-convert-migrate_vma_collect_pmd-to-use-a-folio.patch mm-convert-huge_zero_page-to-huge_zero_folio.patch mm-convert-do_huge_pmd_anonymous_page-to-huge_zero_folio.patch dax-use-huge_zero_folio.patch mm-rename-mm_put_huge_zero_page-to-mm_put_huge_zero_folio.patch mm-use-rwsem-assertion-macros-for-mmap_lock.patch filemap-remove-__set_page_dirty.patch mm-correct-page_mapped_in_vma-for-large-folios.patch mm-remove-vma_address.patch mm-rename-vma_pgoff_address-back-to-vma_address.patch khugepaged-inline-hpage_collapse_alloc_folio.patch khugepaged-convert-alloc_charge_hpage-to-alloc_charge_folio.patch khugepaged-remove-hpage-from-collapse_huge_page.patch khugepaged-pass-a-folio-to-__collapse_huge_page_copy.patch khugepaged-remove-hpage-from-collapse_file.patch khugepaged-use-a-folio-throughout-collapse_file.patch khugepaged-use-a-folio-throughout-collapse_file-fix.patch khugepaged-use-a-folio-throughout-hpage_collapse_scan_file.patch proc-convert-clear_refs_pte_range-to-use-a-folio.patch proc-convert-smaps_account-to-use-a-folio.patch mm-remove-page_idle-and-page_young-wrappers.patch mm-generate-page_idle_flag-definitions.patch proc-convert-gather_stats-to-use-a-folio.patch proc-convert-smaps_page_accumulate-to-use-a-folio.patch proc-pass-a-folio-to-smaps_page_accumulate.patch proc-convert-smaps_pmd_entry-to-use-a-folio.patch mm-remove-struct-page-from-get_shadow_from_swap_cache.patch hugetlb-convert-alloc_buddy_hugetlb_folio-to-use-a-folio.patch mm-convert-pagecache_isize_extended-to-use-a-folio.patch mm-free-non-hugetlb-large-folios-in-a-batch.patch mm-combine-free_the_page-and-free_unref_page.patch mm-inline-destroy_large_folio-into-__folio_put_large.patch mm-combine-__folio_put_small-__folio_put_large-and-__folio_put.patch mm-convert-free_zone_device_page-to-free_zone_device_folio.patch doc-improve-the-description-of-__folio_mark_dirty.patch buffer-add-kernel-doc-for-block_dirty_folio.patch buffer-add-kernel-doc-for-try_to_free_buffers.patch buffer-fix-__bread-and-__bread_gfp-kernel-doc.patch buffer-add-kernel-doc-for-brelse-and-__brelse.patch buffer-add-kernel-doc-for-bforget-and-__bforget.patch buffer-improve-bdev_getblk-documentation.patch doc-split-bufferrst-out-of-api-summaryrst.patch