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Date:   Tue, 3 May 2022 07:35:41 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc:     linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 01/69] scsicam: Fix use of page cache
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On Fri, Apr 29, 2022 at 06:24:48PM +0100, Matthew Wilcox (Oracle) wrote:
> Filesystems do not necessarily set PageError; instead they will leave
> PageUptodate clear on errors.  We should also kmap() the page before
> accessing it in case the page is allocated from HIGHMEM.

The PageError to PageUptodate change looks sane.  But block device
page cache absolutely must not be in highmem, so I don't see a point
in the kmap conversion here.