sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes

diff --cc fs/userfaultfd.c
Simple merge

diff --cc include/linux/mm_types.h
Simple merge

diff --cc kernel/fork.c
Simple merge

diff --cc lib/maple_tree.c
Simple merge

diff --cc mm/huge_memory.c
Simple merge

diff --cc mm/hugetlb.c
Simple merge

diff --cc mm/khugepaged.c
Simple merge

diff --cc mm/memory.c
Simple merge

diff --cc mm/mmap.c
index 511f656eb423827433ba103bbc8bf7b209b65f21,ff68a67a2a7c3477fa19c93d740a3f26617545b9..51cd747884e321a56d778df0b0c1af0bc6e0f7c5
--- 1/mm/mmap.c
--- 2/mm/mmap.c
+++ b/mm/mmap.c
@@@ -3069,8 -3037,9 +3069,9 @@@ void exit_mmap(struct mm_struct *mm
         */
        set_bit(MMF_OOM_SKIP, &mm->flags);
        mmap_write_lock(mm);
+       mt_clear_in_rcu(&mm->mm_mt);
        free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS,
 -                    USER_PGTABLES_CEILING);
 +                    USER_PGTABLES_CEILING, true);
        tlb_finish_mmu(&tlb);
  
        /*

diff --cc mm/mprotect.c
Simple merge

diff --cc mm/swapfile.c
Simple merge

diff --cc mm/vmalloc.c
Simple merge