linux-kernel - Re: [PATCH v6 02/13] iomap: comment on atomic write checks in iomap_dio_bio

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Message-ID: <20250317060828.GB27019@lst.de>
Date: Mon, 17 Mar 2025 07:08:28 +0100
From: Christoph Hellwig <hch@....de>
To: John Garry <john.g.garry@...cle.com>
Cc: brauner@...nel.org, djwong@...nel.org, cem@...nel.org,
	dchinner@...hat.com, hch@....de, linux-xfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	ojaswin@...ux.ibm.com, ritesh.list@...il.com,
	martin.petersen@...cle.com, tytso@....edu,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH v6 02/13] iomap: comment on atomic write checks in
 iomap_dio_bio_iter()

On Thu, Mar 13, 2025 at 05:12:59PM +0000, John Garry wrote:
>  		if (iter->flags & IOMAP_ATOMIC_HW) {
> +			/*
> +			* Ensure that the mapping covers the full write length,
> +			* otherwise we will submit multiple BIOs, which is
> +			* disallowed.
> +			*/

"disallowed" doesn't really explain anything, why is it disallowed?

Maybe:

			* Ensure that the mapping covers the full write length,
			* otherwise it can't be submitted as a single bio,
			* which is required to use hardware atomics.