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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , "Matthew Wilcox (Oracle)" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 02/16] mm: provide vma_[flags_]is_cow_mapping() and remove is_cow_mapping() Message-ID: References: <20260813-b4-scalable-cow-virt-pgoff-v5-0-c21581c0c3c8@kernel.org> <20260813-b4-scalable-cow-virt-pgoff-v5-2-c21581c0c3c8@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260813-b4-scalable-cow-virt-pgoff-v5-2-c21581c0c3c8@kernel.org> X-Rspam-User: X-Stat-Signature: p64i7wrhepmzi7wedoyz985t1kcc6kew X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E36B318000C X-HE-Tag: 1787229683-375490 X-HE-Meta: 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 OG0mZatO Len/bLFWje2jGXkEpIGPbaWHZfhd3PZajuYb/5UWVbAVE8g1Wd70A8N784X0TcSsDqP1YtQXAY7MmfB8RzYgAtvRGYTzvMhN8H2NPV9JolZHMksLG/GkRDaLxaVWjKZhu3u4Gzbalp1uj+PyO5f8JnPxl5VBpnGqK3/ACohSmD4FN/txh4LY9iiaVsx8/eDBxOskewty38+jo1Dfd6vTsZtU1DcJxB+MVjlgW3tSxZywgaIahBjebL3bFtu7ChouZ8hTIp5oJHgnNxO10jEuDT/Urdk/TmRNWy+dpy+o9ALsApe0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: (trim cc-list) On Thu, Aug 13, 2026 at 06:32:19PM +0100, Lorenzo Stoakes (ARM) wrote: ... > diff --git a/include/linux/mm.h b/include/linux/mm.h > index df78847f5f07..199d0a64b14a 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2271,17 +2271,76 @@ void unpin_user_pages(struct page **pages, unsigned long npages); > void unpin_user_folio(struct folio *folio, unsigned long npages); > void unpin_folios(struct folio **folios, unsigned long nfolios); > ... > +/** > + * vma_is_cow_mapping() - Is this VMA a CoW mapping? > + * @desc: The VMA to check. Andrew - a small typo here, this should be @vma not @desc, are you still to fix this in place? If not can always send a fixup patch next cycle :)) (Credit to David's scripts for finding this! :) > + * > + * See vma_flags_is_cow_mapping() for details. > + * > + * Returns: true if the VMA is a CoW mapping, otherwise false. > + */ > +static inline bool vma_is_cow_mapping(const struct vm_area_struct *vma) > { > - return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; > + return vma_flags_is_cow_mapping(&vma->flags); > } > -- Cheers, Lorenzo