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Date: Tue, 28 May 2024 10:12:48 +0200
From: Christoph Hellwig <hch@lst.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna@kernel.org>, linux-nfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/2] filemap: Convert generic_perform_write() to
 support large folios
Message-ID: <20240528081248.GA3192@lst.de>
References: <20240527163616.1135968-1-hch@lst.de> <20240527163616.1135968-2-hch@lst.de> <ZlTOLsrhD4P4Yiwl@casper.infradead.org>
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On Mon, May 27, 2024 at 07:17:18PM +0100, Matthew Wilcox wrote:
> Could you remind me why we need to call flush_dcache_folio() in
> generic_perform_write() while we don't in iomap_write_iter()?

> > -		copied = copy_page_from_iter_atomic(page, offset, bytes, i);
> > -		flush_dcache_page(page);
> > +		copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
> > +		flush_dcache_folio(folio);
> 
> (this one has no equivalent in iomap)

The iomap equivalent is in __iomap_write_end and iomap_write_end_inline
and block_write_end.