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Date: Wed, 10 Jan 2024 11:32:29 -0700
From: Keith Busch <kbusch@kernel.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: io-uring <io-uring@vger.kernel.org>
Subject: Re: [PATCH] io_uring/rw: cleanup io_rw_done()
Message-ID: <ZZ7ivQcfP4rgtbS0@kbusch-mbp>
References: <8182cb84-0fca-43b8-b36f-0287e20184cd@kernel.dk>
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In-Reply-To: <8182cb84-0fca-43b8-b36f-0287e20184cd@kernel.dk>

On Wed, Jan 10, 2024 at 10:09:19AM -0700, Jens Axboe wrote:
> +static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
> +{
> +	if (ret == -EIOCBQUEUED) {
> +		return;
> +	} else if (ret >= 0) {
> +end_io:
> +		INDIRECT_CALL_2(kiocb->ki_complete, io_complete_rw_iopoll,
> +				io_complete_rw, kiocb, ret);
> +	} else {
> +		switch (ret) {
> +		case -ERESTARTSYS:
> +		case -ERESTARTNOINTR:
> +		case -ERESTARTNOHAND:
> +		case -ERESTART_RESTARTBLOCK:
> +			/*
> +			 * We can't just restart the syscall, since previously
> +			 * submitted sqes may already be in progress. Just fail
> +			 * this IO with EINTR.
> +			 */
> +			ret = -EINTR;
> +			WARN_ON_ONCE(1);
> +			break;
> +		}
> +		goto end_io;
> +	}
> +}

Are you just trying to get the most common two conditions at the top? A
little rearringing and you can remove the 'goto'. Maybe just my opinion,
but I find using goto for flow control harder to read if there's a
structured alternative.

static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
	if (ret == -EIOCBQUEUED)
		return;

	if (unlikely(ret < 0)) {
		switch (ret) {
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
		case -ERESTARTNOHAND:
		case -ERESTART_RESTARTBLOCK:
			/*
			 * We can't just restart the syscall, since previously
			 * submitted sqes may already be in progress. Just fail
			 * this IO with EINTR.
			 */
			ret = -EINTR;
			WARN_ON_ONCE(1);
			break;
		}
	}

	INDIRECT_CALL_2(kiocb->ki_complete, io_complete_rw_iopoll,
			io_complete_rw, kiocb, ret);
}