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From: Matthew Wilcox <willy@infradead.org>
To: Yishai Hadas <yishaih@nvidia.com>
Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	linux-mm@kvack.org, jgg@nvidia.com, axboe@kernel.dk,
	logang@deltatee.com, hch@lst.de, alex.williamson@redhat.com,
	leonro@nvidia.com, maorg@nvidia.com
Subject: Re: [PATCH] lib/scatterlist: Fix to calculate the last_pg properly
Date: Tue, 10 Jan 2023 05:08:25 +0000	[thread overview]
Message-ID: <Y7zyyTxdoJulq7OD@casper.infradead.org> (raw)
In-Reply-To: <20230109144701.83021-1-yishaih@nvidia.com>

On Mon, Jan 09, 2023 at 04:47:01PM +0200, Yishai Hadas wrote:
>  	if (sgt_append->prv) {
> +		unsigned long paddr =
> +			(page_to_pfn(sg_page(sgt_append->prv)) * PAGE_SIZE +

1. page_to_pfn() * PAGE_SIZE is spelled page_to_phys()

2. physical addresses have type phys_addr_t.  Oh, wait, paddr isn't a
physical address, it's a pfn because you divide by PAGE_SIZE at the end.
But you will get truncation on 32-bit, because page_to_pfn() has type
unsigned long.  Anyway, this shouldn't be called paddr.  Maybe last_pfn
or something?

> +			 sgt_append->prv->offset + sgt_append->prv->length) /
> +			PAGE_SIZE;


  parent reply	other threads:[~2023-01-10  5:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-09 14:47 Yishai Hadas
2023-01-09 18:08 ` Logan Gunthorpe
2023-01-10  3:18 ` Jens Axboe
2023-01-11  0:03   ` Andrew Morton
2023-01-11 13:28     ` Jason Gunthorpe
2023-01-10  5:08 ` Matthew Wilcox [this message]
2023-01-10  8:01   ` Yishai Hadas
2023-01-10 13:53     ` Jason Gunthorpe
2023-01-10 15:05       ` Yishai Hadas

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