mm/gup: cache p4d in follow_p4d_mask()

Add a variable to cache p4d in follow_p4d_mask().  It's a good practise to
make sure all the following checks will have a consistent view of the
entry.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Peter Xu <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Andreas Larsson <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Bjorn Andersson <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Konrad Dybcio <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Mike Rapoport (IBM) <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: "Naveen N. Rao" <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Russell King <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions