mm/gup: simplify the external interface functions and consolidate invariants

The GUP family of functions have a complex, but fairly well defined, set
of invariants for their arguments.  Currently these are sprinkled about,
sometimes in duplicate through many functions.

Internally we don't follow all the invariants that the external interface
has to follow, so place these checks directly at the exported interface. 
This ensures the internal functions never reach a violated invariant.

Remove the duplicated invariant checks.

The end result is to make these functions fully internal:
 __get_user_pages_locked()
 internal_get_user_pages_fast()
 __gup_longterm_locked()

And all the other functions call directly into one of these.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jason Gunthorpe <[email protected]>
Suggested-by: John Hubbard <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Acked-by: Mike Rapoport (IBM) <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Claudio Imbrenda <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: David Howells <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions