frwr_map(9)

frwr_map(9) 💖

okay so bestie, this page is from the Kernel API Manual and it's all about frwr_map — registering a memory region from an xdr_buf cursor. it's giving kernel memory registration main character energy, no cap. let's get into it ✨

🌸 NAME 🌸

frwr_map — literally registers a memory region from an xdr_buf cursor. periodt. 💅

✨ SYNOPSIS ✨

int frwr_map (struct rpcrdma_xprt *r_xprt , struct rpcrdma_xdr_cursor
*cur , bool writing , __be32 xid , struct rpcrdma_mr *mr );

🎀 ARGUMENTS 🎀

• r_xprt — the controlling transport 🚂
• cur — cursor tracking position within the xdr_buf 📍
• writing — true when RDMA Write will be used ✍️
• xid — XID of RPC using the registered memory 🆔
• mr — MR to fill in 🧁

💅 DESCRIPTION 💅

so what this actually does: prepare a REG_MR Work Request to register a memory region for remote access via RDMA READ or RDMA WRITE. iconic behavior honestly. 👑

it returns 0 on success — cursor advanced past consumed data and mr populated — or a negative errno on failure. 😭💀

🦋 SEE ALSO 🦋

• Kernel file: ./net/sunrpc/xprtrdma/frwr_ops.c
• frwr_mr_release(9)
• frwr_reset(9)
• frwr_mr_init(9)
• frwr_query_device(9)
• frwr_wc_fastreg(9)
• frwr_send(9)
• frwr_reminv(9)
• frwr_wc_localinv(9)
• frwr_wc_localinv_wake(9)
• frwr_unmap_sync(9)
• frwr_wc_localinv_done(9)
• frwr_unmap_async(9)
• frwr_wp_create(9)

and that's the whole page, bestie 🫶 this one lives at source path ./net/sunrpc/xprtrdma, dated October 2026, and it's literally frwr_map(9). periodt. 💖✨