range_is_subset(9)

🌸 NAME 🌸

okay so bestie, meet range_is_subset(9) from the Kernel API Manual 💖 — it's literally asking: is the specified inner range a subset of the outer range? 👑

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✨ SYNOPSIS ✨

the whole vibe is this one-line bop, no cap:

bool range_is_subset (unsigned long outer_start , unsigned long outer_end , unsigned long inner_start , unsigned long inner_end );

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🎀 ARGUMENTS 🎀

• outer_start — the start of the outer range, bestie 🫶
• outer_end — the exclusive end of the outer range, so that endpoint is not included, iykyk ✨
• inner_start — the start of the inner range 🌸
• inner_end — the exclusive end of the inner range, same exclusive-energy, periodt 💅

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💖 RETURN 💖

true if [inner_start, inner_end) is a subset of [outer_start, outer_end), otherwise false. 🦋

that's it, that's the whole vibe check 😭

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🦋 SEE ALSO 🦋

the kernel file ./include/linux/mm.h is the main character here, and then there's this whole squad of SEE ALSO besties:

• Kernel file ./include/linux/mm.h
• folio_page_idx(9)
• vma_flag_t(9)
• fault_flag_allow_retry_first(9)
• vma_kernel_pagesize(9)
• folio_order(9)
• folio_reset_order(9)
• folio_mapcount(9)
• folio_mapped(9)
• thp_order(9)
• thp_size(9)
• folio_get(9)
• folio_put(9)
• folio_put_refs(9)
• folios_put(9)
• vma_flags_is_cow_mapping(9)
• vma_is_cow_mapping(9)
• vma_desc_is_cow_mapping(9)
• folio_pfn(9)
• folio_mk_pte(9)
• folio_mk_pmd(9)
• folio_mk_pud(9)
• folio_maybe_dma_pinned(9)
• is_zero_page(9)
• is_zero_folio(9)
• folio_nr_pages(9)
• folio_next(9)
• folio_shift(9)
• folio_size(9)
• folio_maybe_mapped_shared(9)
• folio_expected_ref_count(9)
• zap_vma(9)
• ptdesc_address(9)
• ptdesc_set_kernel(9)
• ptdesc_clear_kernel(9)
• ptdesc_test_kernel(9)
• pagetable_alloc(9)
• pagetable_free(9)
• vma_lookup(9)
• vma_start_pgoff(9)
• vma_end_pgoff(9)
• vma_last_pgoff(9)
• vma_start_anon_pgoff(9)
• vma_end_anon_pgoff(9)
• vma_last_anon_pgoff(9)
• mmap_action_remap(9)
• mmap_action_remap_full(9)
• mmap_action_ioremap(9)
• mmap_action_ioremap_full(9)
• mmap_action_simple_ioremap(9)
• mmap_action_map_kernel_pages(9)
• mmap_action_map_kernel_pages_full(9)
• range_in_vma(9)
• range_in_vma_desc(9)
• clear_pages(9)

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mwah 💋 — this iconic little page lives in ./include/linux, dated October 2026, and it's literally range_is_subset(9). 🎀