Re: [PATCH 1/3] io_uring/net: only import send_zc buffer once

[Pavel Begunkov]

On 3/21/25 18:48, Caleb Sander Mateos wrote:
> io_send_zc() guards its call to io_send_zc_import() with if (!done_io)
> in an attempt to avoid calling it redundantly on the same req. However,
> if the initial non-blocking issue returns -EAGAIN, done_io will stay 0.
> This causes the subsequent issue to unnecessarily re-import the buffer.
>
> Add an explicit flag "imported" to io_sr_msg to track if its buffer has
> already been imported. Clear the flag in io_send_zc_prep(). Call
> io_send_zc_import() and set the flag in io_send_zc() if it is unset.

lgtm. Maybe there is a way to put it into req->flags and combine
with REQ_F_IMPORT_BUFFER, but likely just an idea for the future.

--
Pavel Begunkov