Commit 91429023 authored by John Hubbard's avatar John Hubbard Committed by Linus Torvalds
Browse files

mm/gup: introduce pin_user_pages_unlocked 



Introduce pin_user_pages_unlocked(), which is nearly identical to the
get_user_pages_unlocked() that it wraps, except that it sets FOLL_PIN
and rejects FOLL_GET.

Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: http://lkml.kernel.org/r/20200518012157.1178336-2-jhubbard@nvidia.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent adc8cb40

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -1713,6 +1713,8 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, 
		    unsigned int gup_flags, struct page **pages, int *locked);

long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,

		    struct page **pages, unsigned int gup_flags);

long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,

		    struct page **pages, unsigned int gup_flags);



int get_user_pages_fast(unsigned long start, int nr_pages,

			unsigned int gup_flags, struct page **pages);

mm/gup.c

+17 −0
Original line number Diff line number Diff line
@@ -2960,3 +2960,20 @@ long pin_user_pages(unsigned long start, unsigned long nr_pages, 
				     pages, vmas, gup_flags);

}

EXPORT_SYMBOL(pin_user_pages);



/*

 * pin_user_pages_unlocked() is the FOLL_PIN variant of

 * get_user_pages_unlocked(). Behavior is the same, except that this one sets

 * FOLL_PIN and rejects FOLL_GET.

 */

long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,

			     struct page **pages, unsigned int gup_flags)

{

	/* FOLL_GET and FOLL_PIN are mutually exclusive. */

	if (WARN_ON_ONCE(gup_flags & FOLL_GET))

		return -EINVAL;



	gup_flags |= FOLL_PIN;

	return get_user_pages_unlocked(start, nr_pages, pages, gup_flags);

}

EXPORT_SYMBOL(pin_user_pages_unlocked);