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Date:   Tue, 25 Jun 2019 09:41:08 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Christoph Hellwig <hch@lst.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
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Subject: Re: [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast
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Message-ID: <20190625074108.GB30815@lst.de>
References: <20190611144102.8848-1-hch@lst.de> <20190611144102.8848-2-hch@lst.de> <20190621133911.GL19891@ziepe.ca>
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On Fri, Jun 21, 2019 at 10:39:11AM -0300, Jason Gunthorpe wrote:
> 
> Hmm, this function, and the other, goes on to do:
> 
>         if (unlikely(!access_ok((void __user *)start, len)))
>                 return 0;
> 
> and I thought that access_ok takes in the tagged pointer?
> 
> How about re-order it a bit?

The patch doesn't really work as-as an misses the main
get_user_pages_fast fast path, but I'll add something equivalent.