mm/mmu_gather: define ENCODED_PAGE_FLAG_DELAY_RMAP

Nowadays, encoded pages are only used in mmu_gather handling.  Let's
update the documentation, and define ENCODED_PAGE_BIT_DELAY_RMAP.  While
at it, rename ENCODE_PAGE_BITS to ENCODED_PAGE_BITS.

If encoded page pointers would ever be used in other context again, we'd
likely want to change the defines to reflect their context (e.g.,
ENCODED_PAGE_FLAG_MMU_GATHER_DELAY_RMAP).  For now, let's keep it simple.

This is a preparation for using the remaining spare bit to indicate that
the next item in an array of encoded pages is a "nr_pages" argument and
not an encoded page.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Reviewed-by: Ryan Roberts <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: "Naveen N. Rao" <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yin Fengwei <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions