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From: Christoph Hellwig <hch@infradead.org>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-mm@kvack.org, John Hubbard <jhubbard@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	William Kucharski <william.kucharski@oracle.com>,
	linux-kernel@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>
Subject: Re: [PATCH v2 06/28] gup: Fix some contiguous memmap assumptions
Date: Mon, 10 Jan 2022 00:29:58 -0800	[thread overview]
Message-ID: <YdvuhjweiC1SjVF4@infradead.org> (raw)
In-Reply-To: <20220110042406.499429-7-willy@infradead.org>

On Mon, Jan 10, 2022 at 04:23:44AM +0000, Matthew Wilcox (Oracle) wrote:
> Several functions in gup.c assume that a compound page has virtually
> contiguous page structs.  This isn't true for SPARSEMEM configs unless
> SPARSEMEM_VMEMMAP is also set.  Fix them by using nth_page() instead of
> plain pointer arithmetic.

So is this an actualy bug that need a Fixes tag, or do all architectures
that support THP and sparsemem use SPARSEMEM_VMEMMAP?

> +	page = nth_page(head, (addr & (sz-1)) >> PAGE_SHIFT);

Would be nice to fix the indeation for sz - 1 while you're at it.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

  reply	other threads:[~2022-01-10  8:31 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-10  4:23 [PATCH v2 00/28] Convert GUP to folios Matthew Wilcox (Oracle)
2022-01-10  4:23 ` [PATCH v2 01/28] gup: Remove for_each_compound_range() Matthew Wilcox (Oracle)
2022-01-10  8:22   ` Christoph Hellwig
2022-01-11  1:07   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 02/28] gup: Remove for_each_compound_head() Matthew Wilcox (Oracle)
2022-01-10  8:23   ` Christoph Hellwig
2022-01-11  1:11   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 03/28] gup: Change the calling convention for compound_range_next() Matthew Wilcox (Oracle)
2022-01-10  8:25   ` Christoph Hellwig
2022-01-11  1:14   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 04/28] gup: Optimise compound_range_next() Matthew Wilcox (Oracle)
2022-01-10  8:26   ` Christoph Hellwig
2022-01-11  1:16   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 05/28] gup: Change the calling convention for compound_next() Matthew Wilcox (Oracle)
2022-01-10  8:27   ` Christoph Hellwig
2022-01-10 13:28     ` Matthew Wilcox
2022-01-11  1:18   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 06/28] gup: Fix some contiguous memmap assumptions Matthew Wilcox (Oracle)
2022-01-10  8:29   ` Christoph Hellwig [this message]
2022-01-10 13:37     ` Matthew Wilcox
2022-01-10 19:05       ` [External] : " Mike Kravetz
2022-01-11  1:47   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 07/28] gup: Remove an assumption of a contiguous memmap Matthew Wilcox (Oracle)
2022-01-10  8:30   ` Christoph Hellwig
2022-01-11  3:27   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 08/28] gup: Handle page split race more efficiently Matthew Wilcox (Oracle)
2022-01-10  8:31   ` Christoph Hellwig
2022-01-11  3:30   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 09/28] gup: Turn hpage_pincount_add() into page_pincount_add() Matthew Wilcox (Oracle)
2022-01-10  8:31   ` Christoph Hellwig
2022-01-11  3:35   ` John Hubbard
2022-01-11  4:32   ` John Hubbard
2022-01-11 13:46     ` Matthew Wilcox
2022-01-10  4:23 ` [PATCH v2 10/28] gup: Turn hpage_pincount_sub() into page_pincount_sub() Matthew Wilcox (Oracle)
2022-01-10  8:32   ` Christoph Hellwig
2022-01-11  6:40   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 11/28] mm: Make compound_pincount always available Matthew Wilcox (Oracle)
2022-01-11  4:06   ` John Hubbard
2022-01-11  4:38     ` Matthew Wilcox
2022-01-11  5:10       ` John Hubbard
2022-01-20  9:15   ` Christoph Hellwig
2022-01-10  4:23 ` [PATCH v2 12/28] mm: Add folio_put_refs() Matthew Wilcox (Oracle)
2022-01-10  8:32   ` Christoph Hellwig
2022-01-11  4:14   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 13/28] mm: Add folio_pincount_ptr() Matthew Wilcox (Oracle)
2022-01-10  8:33   ` Christoph Hellwig
2022-01-11  4:22   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 14/28] mm: Convert page_maybe_dma_pinned() to use a folio Matthew Wilcox (Oracle)
2022-01-10  8:33   ` Christoph Hellwig
2022-01-11  4:27   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 15/28] gup: Add try_get_folio() and try_grab_folio() Matthew Wilcox (Oracle)
2022-01-10  8:34   ` Christoph Hellwig
2022-01-11  5:00   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 16/28] mm: Remove page_cache_add_speculative() and page_cache_get_speculative() Matthew Wilcox (Oracle)
2022-01-10  8:35   ` Christoph Hellwig
2022-01-11  5:14   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 17/28] gup: Add gup_put_folio() Matthew Wilcox (Oracle)
2022-01-10  8:35   ` Christoph Hellwig
2022-01-11  6:44   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 18/28] hugetlb: Use try_grab_folio() instead of try_grab_compound_head() Matthew Wilcox (Oracle)
2022-01-10  8:36   ` Christoph Hellwig
2022-01-11  6:47   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 19/28] gup: Convert try_grab_page() to call try_grab_folio() Matthew Wilcox (Oracle)
2022-01-10  8:36   ` Christoph Hellwig
2022-01-11  7:01   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 20/28] gup: Convert gup_pte_range() to use a folio Matthew Wilcox (Oracle)
2022-01-10  8:37   ` Christoph Hellwig
2022-01-11  7:06   ` John Hubbard
2022-01-10  4:23 ` [PATCH v2 21/28] gup: Convert gup_hugepte() " Matthew Wilcox (Oracle)
2022-01-10  8:37   ` Christoph Hellwig
2022-01-11  7:33   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 22/28] gup: Convert gup_huge_pmd() " Matthew Wilcox (Oracle)
2022-01-10  8:37   ` Christoph Hellwig
2022-01-11  7:36   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 23/28] gup: Convert gup_huge_pud() " Matthew Wilcox (Oracle)
2022-01-10  8:38   ` Christoph Hellwig
2022-01-11  7:38   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 24/28] gup: Convert gup_huge_pgd() " Matthew Wilcox (Oracle)
2022-01-10  8:38   ` Christoph Hellwig
2022-01-11  7:38   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 25/28] gup: Convert compound_next() to gup_folio_next() Matthew Wilcox (Oracle)
2022-01-10  8:39   ` Christoph Hellwig
2022-01-11  7:41   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 26/28] gup: Convert compound_range_next() to gup_folio_range_next() Matthew Wilcox (Oracle)
2022-01-10  8:41   ` Christoph Hellwig
2022-01-10 13:41     ` Matthew Wilcox
2022-01-11  7:44   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 27/28] mm: Add isolate_lru_folio() Matthew Wilcox (Oracle)
2022-01-10  8:42   ` Christoph Hellwig
2022-01-11  7:49   ` John Hubbard
2022-01-10  4:24 ` [PATCH v2 28/28] gup: Convert check_and_migrate_movable_pages() to use a folio Matthew Wilcox (Oracle)
2022-01-10  8:42   ` Christoph Hellwig
2022-01-11  7:52   ` John Hubbard
2022-01-10 15:31 ` [PATCH v2 00/28] Convert GUP to folios Jason Gunthorpe
2022-01-10 16:09   ` Matthew Wilcox
2022-01-10 17:26 ` William Kucharski

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