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From: Matthew Wilcox <willy@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-block@vger.kernel.org
Subject: Re: [PATCH v15 01/17] block: Add bio_add_folio()
Date: Fri, 30 Jul 2021 12:30:57 +0100	[thread overview]
Message-ID: <YQPi8R+Mjh3MxToC@casper.infradead.org> (raw)
In-Reply-To: <YQO3bXpibArh37fH@T590>

On Fri, Jul 30, 2021 at 04:25:17PM +0800, Ming Lei wrote:
> > +size_t bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
> > +		size_t off)
> > +{
> > +	if (len > UINT_MAX || off > UINT_MAX)
> > +		return 0;
> 
> The added page shouldn't cross 4G boundary, so just wondering why not
> check 'if (len > UINT_MAX - off)'?

That check is going to be vulnerable to wrapping, eg
	off = 2^32, len = 512

It would be less vulnerable to wrapping if we cast both sides to
signed long.  But at that point, we're firmly into obscuring the
intent of the check.

  reply	other threads:[~2021-07-30 11:32 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 18:39 [PATCH v15 00/17] Folio support in block + iomap layers Matthew Wilcox (Oracle)
2021-07-19 18:39 ` [PATCH v15 01/17] block: Add bio_add_folio() Matthew Wilcox (Oracle)
2021-07-20  1:28   ` Darrick J. Wong
2021-07-20  6:42   ` Christoph Hellwig
2021-07-20 11:16     ` Matthew Wilcox
2021-07-22 16:27     ` Matthew Wilcox
2021-07-30  8:25   ` Ming Lei
2021-07-30 11:30     ` Matthew Wilcox [this message]
2021-07-19 18:39 ` [PATCH v15 02/17] block: Add bio_for_each_folio_all() Matthew Wilcox (Oracle)
2021-07-20  1:29   ` Darrick J. Wong
2021-07-20  1:59     ` Matthew Wilcox
2021-07-20  6:48   ` Christoph Hellwig
2021-07-23  2:40     ` Matthew Wilcox
2021-07-20 12:05   ` kernel test robot
2021-07-20 12:05     ` kernel test robot
2021-07-20 12:05   ` kernel test robot
2021-07-20 12:05     ` kernel test robot
2021-07-20 12:26   ` kernel test robot
2021-07-20 12:26     ` kernel test robot
2021-07-19 18:39 ` [PATCH v15 03/17] iomap: Convert to_iomap_page to take a folio Matthew Wilcox (Oracle)
2021-07-20  6:49   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 04/17] iomap: Convert iomap_page_create " Matthew Wilcox (Oracle)
2021-07-20  6:50   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 05/17] iomap: Convert iomap_page_release " Matthew Wilcox (Oracle)
2021-07-20  6:52   ` Christoph Hellwig
2021-07-20 11:29     ` Matthew Wilcox
2021-07-20 11:40       ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 06/17] iomap: Convert iomap_releasepage to use " Matthew Wilcox (Oracle)
2021-07-20  6:54   ` Christoph Hellwig
2021-07-20 23:56   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 07/17] iomap: Convert iomap_invalidatepage " Matthew Wilcox (Oracle)
2021-07-20  6:55   ` Christoph Hellwig
2021-07-20 23:57   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 08/17] iomap: Pass the iomap_page into iomap_set_range_uptodate Matthew Wilcox (Oracle)
2021-07-20  6:57   ` Christoph Hellwig
2021-07-20 11:36     ` Matthew Wilcox
2021-07-19 18:39 ` [PATCH v15 09/17] iomap: Use folio offsets instead of page offsets Matthew Wilcox (Oracle)
2021-07-20  6:59   ` Christoph Hellwig
2021-07-20 11:42     ` Matthew Wilcox
2021-07-19 18:39 ` [PATCH v15 10/17] iomap: Convert bio completions to use folios Matthew Wilcox (Oracle)
2021-07-20  7:08   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 11/17] iomap: Convert readahead and readpage to use a folio Matthew Wilcox (Oracle)
2021-07-20  7:09   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 12/17] iomap: Convert iomap_page_mkwrite " Matthew Wilcox (Oracle)
2021-07-20  7:13   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 13/17] iomap: Convert iomap_write_begin and iomap_write_end to folios Matthew Wilcox (Oracle)
2021-07-20  7:15   ` Christoph Hellwig
2021-07-20 23:59   ` Darrick J. Wong
2021-07-19 18:39 ` [PATCH v15 14/17] iomap: Convert iomap_read_inline_data to take a folio Matthew Wilcox (Oracle)
2021-07-20  7:16   ` Christoph Hellwig
2021-07-19 18:39 ` [PATCH v15 15/17] iomap: Convert iomap_write_end_inline " Matthew Wilcox (Oracle)
2021-07-20  7:17   ` Christoph Hellwig
2021-07-19 18:40 ` [PATCH v15 16/17] iomap: Convert iomap_add_to_ioend " Matthew Wilcox (Oracle)
2021-07-20  7:20   ` Christoph Hellwig
2021-07-20 11:45     ` Matthew Wilcox
2021-07-21  0:12   ` Darrick J. Wong
2021-07-21  4:27     ` Christoph Hellwig
2021-07-21  4:31       ` Matthew Wilcox
2021-07-21 15:28         ` Darrick J. Wong
2021-07-19 18:40 ` [PATCH v15 17/17] iomap: Convert iomap_migrate_page to use folios Matthew Wilcox (Oracle)
2021-07-20  7:21   ` Christoph Hellwig
2021-07-20 13:30   ` kernel test robot
2021-07-20 13:30     ` kernel test robot
2021-07-21  0:02   ` Darrick J. Wong
2021-07-20  8:44 ` [PATCH v15 00/17] Folio support in block + iomap layers Christoph Hellwig
2021-07-20 11:08   ` Matthew Wilcox

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