Re: [PATCH v5.5 10/10] mmap locking API: rename mmap_sem to mmap_lock

[John Hubbard]

On 2020-05-19 19:39, Michel Lespinasse wrote:
...

That gives you additional options inside internal_get_user_pages_fast(), such
as, approximately:

if (!(gup_flags & FOLL_FAST_ONLY))
         might_lock_read(&current->mm->mmap_lock);

...not that that is necessarily a great idea, seeing as how it merely changes
"might lock" into "maybe might lock".  :)

I think that is completely fine, makes sure everyone not using
FOLL_FAST_ONLY realizes that the call could block.

Can I ask you to add that assertion in your patchset ? Based on
Matthew's feedback, I would do it in my patchset, but it doesn't seem
worth doing if we know this will conflict with your changes.

Sure, that's no problem. Although it looks like my changes may land
in mmotm first, and then your patchset, so maybe the right move is to
make this change *after* both of those things happen, yes?


thanks,
--
John Hubbard
NVIDIA