On 7/19/19 1:59 PM, Matt Sickler wrote: >> From: Bharath Vedartham <linux.b...@gmail.com> >> Changes since v2 >> - Added back PageResevered check as suggested by John Hubbard. >> >> The PageReserved check needs a closer look and is not worth messing >> around with for now. >> >> Matt, Could you give any suggestions for testing this patch? > > Myself or someone else from Daktronics would have to do the testing since the > hardware isn't really commercially available. I've been toying with the idea > of asking for a volunteer from the mailing list to help me out with this - I'd > send them some hardware and they'd do all the development and testing. :) > I still have to run that idea by Management though. > >> If in-case, you are willing to pick this up to test. Could you >> apply this patch to this tree and test it with your devices? > > I've been meaning to get to testing the changes to the drivers since > upstreaming > them, but I've been swamped with other development. I'm keeping an eye on the > mailing lists, so I'm at least aware of what is coming down the pipe. > I'm not too worried about this specific change, even though I don't really > know > if the reserved check and the dirtying are even necessary. > It sounded like John's suggestion was to not do the PageReserved() check and > just > use put_user_pges_dirty() all the time. John, is that incorrect? >
That's what I suggested at first. But then I saw at least one other place where this pattern is being used, and it shook my confidence. I don't clearly see what the PageReserved check is protecting against here, but it's better to be safe, and do things in two steps: step 1 is *only* convert from put_page() to put_user_page(), and step 2 is to maybe remove the PageReserved() check, once fully understood. thanks, -- John Hubbard NVIDIA
