Messages in this thread | | | Subject | Re: [PATCH v4 2/3] mm: introduce put_user_page*(), placeholder versions | From | John Hubbard <> | Date | Sun, 4 Nov 2018 23:25:31 -0800 |
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On 10/18/18 3:19 AM, Jan Kara wrote: > On Thu 11-10-18 20:53:34, John Hubbard wrote: >> On 10/11/18 6:23 PM, John Hubbard wrote: >>> On 10/11/18 6:20 AM, Jason Gunthorpe wrote: >>>> On Thu, Oct 11, 2018 at 10:49:29AM +0200, Jan Kara wrote: [...] > Well, put_page() cannot assert page is not dma-pinned as someone can still > to get_page(), put_page() on dma-pinned page and that must not barf. But > put_page() could assert that if the page is pinned, refcount is >= > pincount. That will detect leaked pin references relatively quickly. >
That assertion is definitely a life saver. I've been attempting a combination of finishing up more call site conversions, and runtime testing, and this lights up the missing conversions pretty nicely.
As I mentioned in another thread just now, I'll send out an updated RFC this week, so that people can look through it well before the LPC (next week).
thanks, -- John Hubbard NVIDIA
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