swiotlb_alloc_tlb(9)

💅 swiotlb_alloc_tlb(9) — like, the Kernel API Manual, bestie ✨

okay so this is a page from the Kernel API Manual, and it's about swiotlb_alloc_tlb — yes that's the name, yes I said it out loud, no I will not say it again 🫶

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✨ NAME ✨

swiotlb_alloc_tlb — allocate a dynamic IO TLB buffer 🎀

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🦋 SYNOPSIS 🦋

struct page * swiotlb_alloc_tlb (struct device *dev , struct io_tlb_mem
*mem , size_t bytes , u64 phys_limit , gfp_t gfp , void **vaddr );

literally the whole signature, copied exact, no cap 💅

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🌸 ARGUMENTS 🌸

• dev — the Device that we're allocating a memory pool for. it's giving "who is this for" energy 👑
• mem — the SWIOTLB allocator for the pool. the main character of the allocator world fr ✨
• bytes — size of the buffer. how big, bestie 📏
• phys_limit — maximum allowed physical address of the buffer. a hard ceiling, no vibes above this line 🚫
• gfp — the GFP flags for the allocation. it's giving "how should we do this" 😌
• vaddr — receives the virtual address for the allocated buffer. it's an out-param, so it gets filled in, she doesn't give, she receives 💖

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⭐ RETURN ⭐

Allocated pages, or NULL on allocation failure. so like… either you get pages or you get nothing and you have to deal with it 😭 check for NULL, please, I'm begging 🙈

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🌈 SEE ALSO 🌈

Kernel file ./kernel/dma/swiotlb.c, plus the whole friend group — every single one of them, and yes I'm listing all of them because they all matter, periodt:

struct io_tlb_slot(9), struct io_tlb_area(9), swiotlb_adjust_nareas(9), limit_nareas(9), add_mem_pool(9), alloc_dma_pages(9), swiotlb_free_tlb(9), swiotlb_alloc_pool(9), swiotlb_dyn_alloc(9), __swiotlb_find_pool(9), swiotlb_del_pool(9), swiotlb_dev_init(9), swiotlb_align_offset(9), swiotlb_search_pool_area(9), swiotlb_search_area(9), swiotlb_find_slots(9), mem_pool_used(9), mem_used(9), swiotlb_tbl_map_single(9), swiotlb_del_transient(9), is_swiotlb_allocated(9), default_swiotlb_base(9), default_swiotlb_limit(9)

like, that's the whole group chat right there 🫶💀

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kay bye, this page lives in ./kernel/dma and it's dated October 2026 — so yeah, future girl summer, slay 🧚‍♀️💜