Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 8 Apr 2020 09:20:00 -0700 | Subject | Re: [PATCH] mm/gup: Let __get_user_pages_locked() return -EINTR for fatal signal |
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On Wed, Apr 8, 2020 at 8:59 AM Peter Xu <peterx@redhat.com> wrote: > > __get_user_pages_locked() will return 0 instead of -EINTR after commit > 4426e945df588 which added extra code to allow gup detect fatal signal > faster. Restore that behavior.
I've applied this, but it's worth noting that __get_user_pages_locked() can still return 0 in other situations.
I realize that "I got zero pages" is a valid return value, but I do wonder if we should make the rule be that a zero return value isn't possible (return -EAGAIN or whatever if you doin't have the EFAULT/EINTR conditions).
So that you'd always get either an error, or a successful number of pages.
The only case where __get_user_pages_locked() might return zero is if you pass in a zero 'nr_pages', although I suspect even for that case returning -EINVAL might be a better option.
Anyway, this is not a new issue, but I thought I'd mention it.
Linus
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