folio_flush_mapping(9)

💅 folio_flush_mapping(9) 💅

okay so bestie, this page is from the Kernel API Manual, and it's about folio_flush_mapping(9) — a very specific little helper with a very specific job. no cap, it's giving niche but iconic. 🎀

💖 NAME 💖

folio_flush_mapping — find the file mapping this folio belongs to. 🦋

✨ SYNOPSIS ✨

struct address_space * folio_flush_mapping (struct folio *folio );

🌸 ARGUMENTS 🌸

• folio — the folio. that's the whole argument, bestie. she's lowkey simple like that. 💜

🔥 DESCRIPTION 🔥

okay so here's the vibe: for folios that are in the page cache, folio_flush_mapping() returns the mapping that this page belongs to. slay. ✨

Anonymous folios return NULL, even if they're in the swap cache. and other kinds of folio also return NULL. no exceptions, no drama. 😭

⚠️ this is ONLY used by architecture cache flushing code. like, ONLY only. if you aren't writing cache flushing code, you want either folio_mapping or folio_file_mapping instead — periodt. 💅

👯 SEE ALSO 👯

Kernel file ./include/linux/pagemap.h is in the group chat, along with all these besties:

• 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_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_file_page(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)

signed, sealed, delivered with 💖 — source/version ./include/linux, date October 2026, page folio_flush_mapping(9). 🎀✨