FROMLIST: mm: cache some VMA fields in the vm_fault structure

When handling speculative page fault, the vma->vm_flags and
vma->vm_page_prot fields are read once the page table lock is released. So
there is no more guarantee that these fields would not change in our back.
They will be saved in the vm_fault structure before the VMA is checked for
changes.

This patch also set the fields in hugetlb_no_page() and
__collapse_huge_page_swapin even if it is not need for the callee.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Change-Id: I9821f02ea32ef220b57b8bfd817992bbf71bbb1d
Link: https://lore.kernel.org/lkml/1523975611-15978-13-git-send-email-ldufour@linux.vnet.ibm.com/


Bug: 161210518
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>