Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 27 Aug 2020 10:13:49 -0700 | Subject | Re: [PATCH v5 6/7] mm/gup: Take mmap_lock in get_dump_page() |
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On Thu, Aug 27, 2020 at 4:50 AM Jann Horn <jannh@google.com> wrote: > > Properly take the mmap_lock before calling into the GUP code from > get_dump_page(); and play nice, allowing the GUP code to drop the mmap_lock > if it has to sleep.
Hmm. Of all the patches in the series, this simple one is now the only one I feel makes for ugly code. Certainly not uglier than it used to be, but also not as pretty as it could be..
I think you're pretty much just re-implementing get_user_pages_unlocked(), aren't you?
There are differences - you use mmap_read_lock_killable(), for example. But I think get_user_pages_unlocked() should too.
The other difference is that you don't set FOLL_TOUCH. So it's not *exactly* the same thing, but it's close enough that I get the feeling that this should be cleaned up to use a common helper between the two.
That said, I suspect that falls under the heading of "future cleanup". I don't think there's any need to re-spin this series for this, it's just the only slightly negative reaction I had for the whole series now.
Linus
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