frwr_unmap_sync(9)

✨ frwr_unmap_sync(9) — Kernel API Manual ✨

okay bestie, this is frwr_unmap_sync(9) from the Kernel API Manual, and it's giving memory-region cleanup realness 💅

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🌸 NAME 🌸

frwr_unmap_sync — invalidate memory regions that were registered for @req 🎀

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🦋 SYNOPSIS 🦋

void frwr_unmap_sync (struct rpcrdma_xprt *r_xprt , struct rpcrdma_req
       *req );

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🌼 ARGUMENTS 🌼

• r_xprt — the controlling transport instance, aka the main character handling the transport vibes ✨
• req — an rpcrdma_req with a non-empty list of MRs to process, no empty-list nonsense here 🫶

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💅 DESCRIPTION 💅

So it sleeps until it is safe for the host CPU to access the previously mapped memory regions 😴✨

This guarantees that registered MRs are properly fenced from the server before the RPC consumer accesses the data in them 🔥 no cap, that fence has to be fenced.

It also ensures proper Send flow control: waking the next RPC waits until this RPC has relinquished all its Send Queue entries 👑 the way it makes the next RPC wait its turn is honestly iconic.

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🔥 SEE ALSO 🔥

• Kernel file ./net/sunrpc/xprtrdma/frwr_ops.c and the whole squad: frwr_mr_release(9), frwr_reset(9), frwr_mr_init(9), frwr_query_device(9), frwr_map(9), frwr_wc_fastreg(9), frwr_send(9), frwr_reminv(9), frwr_wc_localinv(9), frwr_wc_localinv_wake(9), frwr_wc_localinv_done(9), frwr_unmap_async(9), frwr_wp_create(9) 💖

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cute little sign-off bestie: source/version is ./net/sunrpc/xprtrdma, date is October 2026, and the page is frwr_unmap_sync(9) — periodt 🌈💜