Re: [PATCH v11 2/8] iov_iter: Add a function to extract a page list from an iterator

[David Howells]

Al says that pinning a page (ie. FOLL_PIN) could cause a deadlock if a page is
vmspliced into a pipe with the pipe holding a pin on it because pinned pages
are removed from all page tables.  Is this actually the case?  I can't see
offhand where in mm/gup.c it does this.

David