mm/mprotect: drop pgprot_t parameter from change_protection()

Being able to provide a custom protection opens the door for
inconsistencies and BUGs: for example, accidentally allowing for more
permissions than desired by other mechanisms (e.g., softdirty tracking). 
vma->vm_page_prot should be the single source of truth.

Only PROT_NUMA is special: there is no way we can erroneously allow
for more permissions when removing all permissions. Special-case using
the MM_CP_PROT_NUMA flag.

[[email protected]: PAGE_NONE might not be defined without CONFIG_NUMA_BALANCING]  
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Peter Xu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions