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Date: Mon, 25 Aug 2025 07:57:49 -0600
From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@meta.com>, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	snitzer@kernel.org, axboe@kernel.dk, dw@davidwei.uk,
	brauner@kernel.org, martin.petersen@oracle.com, djwong@kernel.org,
	linux-xfs@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Re: [PATCHv3 3/8] block: align the bio after building it
Message-ID: <aKxr3a74EjiyEUUA@kbusch-mbp>
References: <20250819164922.640964-1-kbusch@meta.com>
 <20250819164922.640964-4-kbusch@meta.com>
 <20250825074606.GE20853@lst.de>
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In-Reply-To: <20250825074606.GE20853@lst.de>

On Mon, Aug 25, 2025 at 09:46:06AM +0200, Christoph Hellwig wrote:
> On Tue, Aug 19, 2025 at 09:49:17AM -0700, Keith Busch wrote:
> > +
> > +	if (!bio->bi_iter.bi_size)
> > +		return -EFAULT;
> 
> And as bi_size doesn't change in the loop, this should probably move
> above the loop.

The loop also releases pinned pages if necessary. We can't count on the
caller to do that if we return error here.  __blkdev_direct_IO is the
only one that tries to release pages on error, everyone else would leak
them.