+ mm-gup-add-foll_longterm-capability-to-gup-fast-v3.patch added to -mm tree

[akpm@xxxxxxxxxxxxxxxxxxxx]

The patch titled
     Subject: mm-gup-add-foll_longterm-capability-to-gup-fast-v3
has been added to the -mm tree.  Its filename is
     mm-gup-add-foll_longterm-capability-to-gup-fast-v3.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-gup-add-foll_longterm-capability-to-gup-fast-v3.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-gup-add-foll_longterm-capability-to-gup-fast-v3.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Ira Weiny <ira.weiny@xxxxxxxxx>
Subject: mm-gup-add-foll_longterm-capability-to-gup-fast-v3

Changes from V2:
	Add comment on special use case of FOLL_LONGTERM

Link: http://lkml.kernel.org/r/20190328084422.29911-5-ira.weiny@xxxxxxxxx
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Marshall <hubcap@xxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/gup.c |   39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

--- a/mm/gup.c~mm-gup-add-foll_longterm-capability-to-gup-fast-v3
+++ a/mm/gup.c
@@ -2043,6 +2043,29 @@ int __get_user_pages_fast(unsigned long
 	return nr;
 }
 
+static int __gup_longterm_unlocked(unsigned long start, int nr_pages,
+				   unsigned int gup_flags, struct page **pages)
+{
+	int ret;
+
+	/*
+	 * FIXME: FOLL_LONGTERM does not work with
+	 * get_user_pages_unlocked() (see comments in that function)
+	 */
+	if (gup_flags & FOLL_LONGTERM) {
+		down_read(&current->mm->mmap_sem);
+		ret = __gup_longterm_locked(current, current->mm,
+					    start, nr_pages,
+					    pages, NULL, gup_flags);
+		up_read(&current->mm->mmap_sem);
+	} else {
+		ret = get_user_pages_unlocked(start, nr_pages,
+					      pages, gup_flags);
+	}
+
+	return ret;
+}
+
 /**
  * get_user_pages_fast() - pin user pages in memory
  * @start:	starting user address
@@ -2088,20 +2111,8 @@ int get_user_pages_fast(unsigned long st
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		if (gup_flags & FOLL_LONGTERM) {
-			down_read(&current->mm->mmap_sem);
-			ret = __gup_longterm_locked(current, current->mm,
-						    start, nr_pages - nr,
-						    pages, NULL, gup_flags);
-			up_read(&current->mm->mmap_sem);
-		} else {
-			/*
-			 * retain FAULT_FOLL_ALLOW_RETRY optimization if
-			 * possible
-			 */
-			ret = get_user_pages_unlocked(start, nr_pages - nr,
-						      pages, gup_flags);
-		}
+		ret = __gup_longterm_unlocked(start, nr_pages - nr,
+					      gup_flags, pages);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
_

Patches currently in -mm which might be from ira.weiny@xxxxxxxxx are

mm-gup-replace-get_user_pages_longterm-with-foll_longterm.patch
mm-gup-replace-get_user_pages_longterm-with-foll_longterm-v3.patch
mm-gup-change-write-parameter-to-flags-in-fast-walk.patch
mm-gup-change-gup-fast-to-use-flags-rather-than-a-write-bool.patch
mm-gup-add-foll_longterm-capability-to-gup-fast.patch
mm-gup-add-foll_longterm-capability-to-gup-fast-v3.patch
ib-hfi1-use-the-new-foll_longterm-flag-to-get_user_pages_fast.patch
ib-hfi1-use-the-new-foll_longterm-flag-to-get_user_pages_fast-v3.patch
ib-qib-use-the-new-foll_longterm-flag-to-get_user_pages_fast.patch
ib-mthca-use-the-new-foll_longterm-flag-to-get_user_pages_fast.patch