STRUCT RPCRDMA_XDR_CURSOR(9)

okay so bestie, welcome to the struct rpcrdma_xdr_cursor(9) page from the Kernel API Manual 💖 this one is literally about a struct that tracks position within an xdr_buf for iterative MR registration, and yes it's giving very niche but very iconic energy ✨

💖 NAME 💖

struct rpcrdma_xdr_cursor — tracks position within an xdr_buf for iterative MR registration. Slay 🎀

✨ SYNOPSIS ✨

here's the exact struct shape, bestie — no cap, copy it character for character:

       struct rpcrdma_xdr_cursor {
           const struct xdr_buf            *xc_buf;
           unsigned int                    xc_page_offset;
           unsigned int                    xc_flags;
        };

🌸 Members 🌸

• xc_buf — the xdr_buf being iterated 🦋
• xc_page_offset — byte offset into the page region consumed so far 👑
• xc_flags — combination of XC_* bits ⭐

💜 Description 💜

okay so each XC_*_DONE flag means this region has no remaining MR registration work. That condition holds both when the region has already been registered by a prior frwr_map call and when the region is excluded from this chunk type (pre-set at init time by rpcrdma_xdr_cursor_init) — iykyk 😭

and frwr_map treats the two cases identically: skip the region. periodt 💅

🔥 SEE ALSO 🔥

• Kernel file ./net/sunrpc/xprtrdma/xprt_rdma.h
• rpcrdma_regbuf_is_mapped(9)
• rpcrdma_regbuf_dma_map(9)

signed off with sparkles: source/version ./net/sunrpc/xprtrdma, date October 2026, page struct rpcrdma_xdr_cursor(9) 🫶✨