svc_rdma_read_special(9)

📦 version 7.3.1, in nixpkgs unstable

💅 svc_rdma_read_special — the Kernel API Manual page you actually want to read 🎀

Okay so bestie, this one lives in the Kernel API Manual and it's lowkey iconic. It's called svc_rdma_read_special and yes, it is that girl — the one that builds RDMA Read WQEs to pull a Long Message. Let's get into it ✨

🌸 SYNOPSIS 🌸

int svc_rdma_read_special (struct svc_rqst *rqstp , struct
svc_rdma_recv_ctxt *head );

Like, that's the whole signature. She's a function. She returns an int. Slay.

🦋 ARGUMENTS 🦋

  • rqstp — the RPC transaction context. Your main character struct, fr fr 💖
  • head — the context for the ongoing I/O. She's holding the vibes together 🫶

✨ DESCRIPTION ✨

So here's the tea ☕: the start of the data lands in the first page, just after the Transport header, and the rest of it lands in rqstp->rq_arg.pages. That's it. That's the whole layout bestie, no cap 💅

Assumptions:

  • A PZRC is never sent in an RDMA_MSG message, though it's allowed by spec. (The spec said she could, but she simply didn't. Respect. 🙈)

💀 Return values — the vibe check 💀

  • 0 — RDMA Read WQEs were successfully built. Ate. 🔥
  • -EINVAL — the client provided too many chunks or segments. Not her fault, the client is doing too much 😭
  • -ENOMEM — the rdma_rw context pool was exhausted. She's running on empty, bestie 🍓
  • -ENOTCONN — posting failed (connection is lost). She ghosted you fr fr 💔
  • -EIO — rdma_rw initialization failed (DMA mapping, etc). The DMA mapping said nope 🙈
Heads up: those negative codes are errors, okay? Don't let a -EINVAL slide past you — check your chunks and segments before she gets mad 😤

👑 SEE ALSO 👑

Kernel file ./net/sunrpc/xprtrdma/svc_rdma_rw.c — that's the source, go look, iykyk 🌈

And her whole friend group, because she does not work alone:

Like, the whole squad. Go read them too, bestie, they're all serving 💜

Okay that's the whole page!! Love that for us. 🧚

Fr fr, this is from ./net/sunrpc/xprtrdma, dated October 2026, in the Kernel API Manual — swiped straight from svc_rdma_read_special(9) itself. Byeee 💖✨

📦 where this page comes from