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Date: Sun, 17 May 2020 18:21:56 -0700 From: John Hubbard <jhubbard@...dia.com> To: Andrew Morton <akpm@...ux-foundation.org> CC: Andy Walls <awalls@...metrocast.net>, Mauro Carvalho Chehab <mchehab@...nel.org>, <linux-media@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>, John Hubbard <jhubbard@...dia.com> Subject: [PATCH 1/2] 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: John Hubbard <jhubbard@...dia.com> --- include/linux/mm.h | 2 ++ mm/gup.c | 17 +++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5a323422d783..a5594ac9ebe3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1702,6 +1702,8 @@ 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); diff --git a/mm/gup.c b/mm/gup.c index 87a6a59fe667..50cd9323efff 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2939,3 +2939,20 @@ 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); base-commit: b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce prerequisite-patch-id: 0496235d2f0b29f75b9835e63a6923ddad6d0260 prerequisite-patch-id: 2711b9393a74cd0e1fcf48befea3618f7bb1ca9e prerequisite-patch-id: 95e2521748b3058710fb2a161b2c76389644665b prerequisite-patch-id: eeae300399f69db2cd61535b40c1f1ee1929195a prerequisite-patch-id: 9ed26cdb071ab084a204c85a08986806d6bae877 -- 2.26.2
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