folio_file_page(9)

💅 folio_file_page — a kernel API manual page, bestie edition 🎀

okay so this is folio_file_page(9), and it lives in the Kernel API Manual. it's short, it's sweet, and it slays at exactly one job: handing you the page that belongs to a specific index inside a folio. let's go ✨

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🌸 NAME 🌸

folio_file_page — literally just: the page for a particular index. that's the whole vibe. 🫶

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✨ SYNOPSIS ✨

struct page * folio_file_page (struct folio *folio , pgoff_t index );

like, you give it a folio and an index, and it gives you back a struct page *. no cap. 💫

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🦋 ARGUMENTS 🦋

• folio — the folio that contains this index. she's the container, the main character, the one holding all the pages together 👑
• index — the index we want to look up. this is the lil coordinate you're asking about 🔍

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💖 DESCRIPTION 💖

sometimes, after you've looked up a folio in the page cache, you still need to get the specific page for an index — like, for example, during a page fault. that's the whole situation this function exists for. it's giving "i have the group, now give me the individual bestie." 🙈✨

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🔥 RETURN 🔥

it returns the page containing the file data for this index. that's it, that's the return value, and she ate 💅

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🌈 SEE ALSO 🌈

the kernel file ./include/linux/pagemap.h, plus this absolute stack of related entries — i'm listing every single one because we don't do crumbs here 🍓

• filemap_set_wb_err(9)
• filemap_check_wb_err(9)
• filemap_sample_wb_err(9)
• file_sample_sb_err(9)
• mapping_set_error(9)
• mapping_set_large_folios(9)
• mapping_align_index(9)
• mapping_pmd_folio_support(9)
• folio_flush_mapping(9)
• folio_inode(9)
• folio_attach_private(9)
• folio_change_private(9)
• folio_detach_private(9)
• fgf_t(9)
• fgf_set_order(9)
• write_begin_get_folio(9)
• filemap_get_folio(9)
• filemap_lock_folio(9)
• filemap_grab_folio(9)
• find_get_page(9)
• find_lock_page(9)
• find_or_create_page(9)
• grab_cache_page_nowait(9)
• folio_next_index(9)
• folio_next_pos(9)
• folio_contains(9)
• page_pgoff(9)
• folio_pos(9)
• linear_page_delta(9)
• linear_page_index(9)
• linear_anon_page_index(9)
• folio_trylock(9)
• folio_lock(9)
• lock_page(9)
• folio_lock_killable(9)
• filemap_range_needs_writeback(9)
• struct readahead_control(9)
• page_cache_sync_readahead(9)
• page_cache_async_readahead(9)
• readahead_folio(9)
• readahead_pos(9)
• readahead_length(9)
• readahead_index(9)
• readahead_count(9)
• readahead_batch_length(9)
• folio_mkwrite_check_truncate(9)
• i_blocks_per_folio(9)

iykyk, that's a lot of folio lore 💀 but go read them, they're all right there 🧚

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ok that's the whole page!! tiny page, huge energy 💜

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sign-off time: this one's sourced from ./include/linux and dated October 2026. periodt. 🎀✨