ib_dma_map_bvec(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ib_dma_map_bvec — like, the kernel API manual, but make it make sense

okay so bestie, this is a page from the Kernel API Manual (ib_dma_map_bvec(9), section 9) and honestly? it's short but it matters. buckle up 🎀

✨ NAME ✨

ib_dma_map_bvec — the girlies that map a bio_vec to a DMA address 💫

🌸 SYNOPSIS 🌸

u64 ib_dma_map_bvec (struct ib_device *dev , struct bio_vec *bvec , enum
dma_data_direction direction );

that's the whole signature, no cap. u64 in, vibes out ✨

🦋 ARGUMENTS 🦋

  • dev — the device the dma_addr is gonna be created for. like, the main character of this whole operation 👑
  • bvec — the bio_vec we're mapping. yes queen, that one 🍓
  • direction — the direction of the DMA. gotta know which way the data's flowing fr fr 🌈

💖 DESCRIPTION 💖

so what it does: it returns a DMA address for the bio_vec. that's the whole slay 💅

BUT — and this is the part where you listen to me — the caller must check the result with ib_dma_mapping_error before use. periodt. and a failed mapping must not be passed to ib_dma_unmap_bvec. like ever. don't do it. i'm serious 😭

⚠️ okay so real talk: ib_dma_mapping_error check = mandatory before you touch that result. failed mapping → never hand it to ib_dma_unmap_bvec. that's the rule, bestie, and it's not negotiable 💀

and for software RDMA devices (rxe, siw), it returns a virtual address and no actual DMA mapping occurs. lowkey iconic behaviour honestly 🌸

🔥 SEE ALSO 🔥

okay this list is long — like, unhinged long — but every single one is here because i would never do you dirty like that. also peep the kernel file ./include/rdma/ib_verbs.h 👀

ik that was a lot but we got through it together 🫶

and that's the page!! 🧚 this little beauty lives at ./include/rdma, it's dated October 2026, and it answers to the name ib_dma_map_bvec(9) — mwah, go check your mapping errors, ily, bye 💜🎀

📦 where this page comes from