On 8/6/19 11:34 PM, Christoph Hellwig wrote:

On Mon, Aug 05, 2019 at 03:54:35PM -0700, John Hubbard wrote:

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On 7/23/19 11:17 PM, Christoph Hellwig wrote:

...

quoted

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I think we can do this in a simple and better way.  We have 5 ITER_*
types.  Of those ITER_DISCARD as the name suggests never uses pages, so
we can skip handling it.  ITER_PIPE is rejected іn the direct I/O path,
which leaves us with three.

Hi Christoph,

Are you working on anything like this?

I was hoping I could steer you towards it.  But if you don't want to do
it yourself I'll add it to my ever growing todo list.

Sure, I'm up for this. The bvec-related items are the next logical part
of the gup/dma conversions to work on, and I just wanted to avoid solving the
same problem if you were already in the code.

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Or on the put_user_bvec() idea?

I have a prototype from two month ago:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/gup-bvec

but that only survived the most basic testing, so it'll need more work,
which I'm not sure when I'll find time for.

I'll take a peek, and probably pester you with a few questions if I get
confused. :)

thanks,
-- 
John Hubbard
NVIDIA