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Date: Fri, 18 Sep 2026 10:43:15 +0200
From: Christoph Hellwig <hch@lst.de>
To: Tal Zussman <tz2294@columbia.edu>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Hannes Reinecke <hare@kernel.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	John Garry <john.g.garry@oracle.com>,
	Christian Brauner <brauner@kernel.org>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Keith Busch <kbusch@kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sashiko <sashiko-bot@kernel.org>
Subject: Re: [PATCH v3 6/7] block: unpin all pages of a bvec in
 bio_iov_iter_align_down()
Message-ID: <20260918084315.GA12283@lst.de>
References: <20260909-blkdev-fixes-v3-0-1a5222c6e8ad@columbia.edu> <20260909-blkdev-fixes-v3-6-1a5222c6e8ad@columbia.edu>
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User-Agent: Mutt/1.5.17 (2007-11-01)

> +
> +	/*
> +	 * __bio_release_pages() only unpins the pages still covered by
> +	 * bv_len, so drop the pins for the pages trimmed off here.
> +	 */
> +	npages = bvec_nr_pages(bv);
>  	bv->bv_len -= nbytes;
> +	npages -= bvec_nr_pages(bv);

Wouldn't it make more sense to calculate npages once after the
decrement here, or am I missing something?