Re: [PATCH] staging: kpc2000: kpc_dma: Convert get_user_pages() --> pin_user_pages()

From: John Hubbard
Date: Mon Jun 08 2020 - 15:22:12 EST


On 2020-06-08 12:16, Dan Carpenter wrote:
On Mon, Jun 08, 2020 at 12:05:57PM -0700, John Hubbard wrote:
On 2020-06-08 12:01, Souptick Joarder wrote:
On Mon, Jun 1, 2020 at 7:15 AM John Hubbard <jhubbard@xxxxxxxxxx> wrote:

On 2020-05-31 10:51, Souptick Joarder wrote:
In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information.

When pin_user_pages() returns numbers of partially mapped pages,
those pages were not unpinned as part of error handling. Fixed
it as part of this patch.


Hi Souptick,

btw, Bharath (+cc) attempted to do the "put" side of this, last year.
That got as far as a v4 patch [1], and then I asked him to let me put
it into my tree. But then it didn't directly apply anymore after the
whole design moved to pin+unpin, and so here we are now.


If Bharath is still doing kernel work, you might offer him a Co-Developed-by:
tag (see https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html).

Sure, will add him as *Co-Developed-by*



Yes, but it's best to wait and see if he responds, before adding that tag, because
it also required a Signed-off-by from him.

Souptick is porting patches from your tree? It's not clear to me how
Bharath actually helped author this patch.


What happened is that Bharath wrote patches very similar to these, last year.
And we spent some time on review and figuring out pre-existing issues in the code.

Anyway, I suspect that he's not actually involved anymore, so I probably shouldn't
have done any more than to just put him on Cc. Sorry for any confusion I created
here.

thanks,
--
John Hubbard
NVIDIA