netdev - Re: [PATCH 2/5] io_uring/poll: introduce io_arm

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Message-ID: <bf6aa4f9-7c6f-4e28-88c0-0e20c5e4a854@gmail.com>
Date: Sat, 31 May 2025 11:28:48 +0100
From: Pavel Begunkov <asml.silence@...il.com>
To: io-uring@...r.kernel.org, Vadim Fedorenko <vadim.fedorenko@...ux.dev>
Cc: netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
 Kuniyuki Iwashima <kuniyu@...zon.com>, Paolo Abeni <pabeni@...hat.com>,
 Willem de Bruijn <willemb@...gle.com>, "David S . Miller"
 <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
 Richard Cochran <richardcochran@...il.com>
Subject: Re: [PATCH 2/5] io_uring/poll: introduce io_arm_apoll()

On 5/30/25 13:18, Pavel Begunkov wrote:
> In preparation to allowing commands to do file polling, add a helper
> that takes the desired poll event mask and arms it for polling. We won't
> be able to use io_arm_poll_handler() with IORING_OP_URING_CMD as it
> tries to infer the mask from the opcode data, and we can't unify it
> across all commands.
> 
> Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
> ---
... -		if (req->flags & REQ_F_CLEAR_POLLIN)
> -			mask &= ~EPOLLIN;
> -	} else {
> -		mask |= EPOLLOUT | EPOLLWRNORM;
> -	}
> -	if (def->poll_exclusive)
> -		mask |= EPOLLEXCLUSIVE;
> -
>   	apoll = io_req_alloc_apoll(req, issue_flags);
>   	if (!apoll)
>   		return IO_APOLL_ABORTED;
> @@ -712,6 +696,31 @@ int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
>   	return IO_APOLL_OK;
>   }
>   
> +int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
> +{
> +	const struct io_issue_def *def = &io_issue_defs[req->opcode];
> +	__poll_t mask = POLLPRI | POLLERR | EPOLLET;
> +
> +	if (!def->pollin && !def->pollout)
> +		return IO_APOLL_ABORTED;
> +	if (!io_file_can_poll(req))
> +		return IO_APOLL_ABORTED;
> +
> +	if (def->pollin) {
> +		mask |= EPOLLIN | EPOLLRDNORM;
> +
> +		/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
> +		if (req->flags & REQ_F_CLEAR_POLLIN)
> +		mask &= ~EPOLLIN;

fwiw, I need to fix tabulation here

> +	} else {
> +		mask |= EPOLLOUT | EPOLLWRNORM;
> +	}
> +	if (def->poll_exclusive)
> +		mask |= EPOLLEXCLUSIVE;
> +
> +	return io_arm_apoll(req, issue_flags, mask);
> +}
-- 
Pavel Begunkov