Messages in this thread | | | Subject | Re: [PATCH 1/2] tomoyo: Convert get_user_pages*() to pin_user_pages*() | From | Tetsuo Handa <> | Date | Sun, 8 Nov 2020 10:13:55 +0900 |
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On 2020/11/08 4:17, John Hubbard wrote: > On 11/7/20 1:04 AM, John Hubbard wrote: >> On 11/7/20 12:24 AM, 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. This is case 5 as per document [1]. >> >> It turns out that Case 5 can be implemented via a better pattern, as long >> as we're just dealing with a page at a time, briefly: >> >> lock_page() >> write to page's data >> unlock_page() >> >> ...which neatly synchronizes with writeback and other fs activities. > > Ahem, I left out a key step: set_page_dirty()! > > lock_page() > write to page's data > set_page_dirty() > unlock_page() >
Excuse me, but Documentation/core-api/pin_user_pages.rst says "CASE 5: Pinning in order to _write_ to the data within the page" while tomoyo_dump_page() is for "_read_ the data within the page". Do we want to convert to pin_user_pages_remote() or lock_page() ?
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