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* [PATCH v5 0/5] mm/gup: some cleanups
@ 2022-02-07  6:22 John Hubbard
  2022-02-07  6:22 ` [PATCH v5 1/5] mm: Fix invalid page pointer returned with FOLL_PIN gups John Hubbard
                   ` (5 more replies)
  0 siblings, 6 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard

Hi,

Here's an update, mainly just collecting reviewed-by tags:

Changes since v4:

    * Patch 1: reflowed the commit description to 72 columns.

    * Added reviewed-by's from Christoph and Jan for remaining patches.

    * Rebased onto 5.17-rc3.


Changes since v3:

    * Patch 1: Commit log: removed a reference to an out of tree module,
      and updated tags and added a short note to that effect.

    * Patch 2: Fixed up do_move_pages(), to squash -EEXIST returns from
      follow_page() into something that move_pages() allows: -EFAULT.
      This is from reviews by Jan Kara, Matthew Wilcox, Jason Gunthorpe.

      Removed all Reviewed-by tags for this patch, due to that update.

    * Patch 4: Split into two patches, as recommended by Christoph
      Hellwig. Left the Reviewed-by tags intact because no code changes
      were required.

    * Added Reviewed-by tags from Claudio Imbrenda.

Changes since v2:

    * Patch 2: Removed an unnecessary line that was causing a
      clang-analyzer complaint, as reported by Lukas Bulwahn
      [1] (thanks!), and retested locally.

      Jason: I've boldly left your Reviewed-by tag on this patch,
      because I am predicting you'll agree with it...

    * Added Reviewed-by tags from Jan Kara, Christoph Hellwig, and
      Jason Gunthorpe that have collected since v2.


Changes since v1:
    * Patch 4: changed from get_user_pages(), to get_user_pages_fast().

    * Patch 4: Rewrote the commit description--thanks to Jan Kara for
               that feedback.

    * Patch 1: Removed Jerome's Cc from patch 1, due to a stale email
               address.

    * Added Reviewed-by's from David Hildenbrand and Jason Gunthorpe.

Original cover letter, updated as necessary:

I'm including Peter's patch as the first one in this tiny series. (The
commit description has my r-b tag in place of my Cc, and removes
Jerome's Cc because he is no longer at redhat.com) The second patch is
what I had in mind for a follow-up to that, when we were discussing that
fix [2].

Plus, a couple more small removals that I had queued up:

The third patch removes a completely unused routine:
pin_user_pages_locked().

The forth patch removes a similar routine, get_user_pages_locked(), that
only has one caller. It now calls get_user_pages_fast(), instead.

v1 of this patchset is here:
https://lore.kernel.org/all/20220131051752.447699-1-jhubbard@nvidia.com/

v2:
https://lore.kernel.org/r/20220201101108.306062-1-jhubbard@nvidia.com

v3:
https://lore.kernel.org/r/20220203093232.572380-1-jhubbard@nvidia.com

v4:
https://lore.kernel.org/r/20220204020010.68930-1-jhubbard@nvidia.com


[1] https://lore.kernel.org/r/CAKXUXMxFK9bo8jDoRZbQ0r2j-JwAGg3Xc5cpAcLaHfwHddJ7ew@mail.gmail.com

[2] https://lore.kernel.org/all/20220125033700.69705-1-peterx@redhat.com/


John Hubbard (4):
  mm/gup: follow_pfn_pte(): -EEXIST cleanup
  mm/gup: remove unused pin_user_pages_locked()
  mm: change lookup_node() to use get_user_pages_fast()
  mm/gup: remove unused get_user_pages_locked()

Peter Xu (1):
  mm: Fix invalid page pointer returned with FOLL_PIN gups

 include/linux/mm.h |   4 --
 mm/gup.c           | 101 ++++-----------------------------------------
 mm/mempolicy.c     |  21 ++++------
 mm/migrate.c       |   7 ++++
 4 files changed, 24 insertions(+), 109 deletions(-)


base-commit: dfd42facf1e4ada021b939b4e19c935dcdd55566
-- 
2.35.1



^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH v5 1/5] mm: Fix invalid page pointer returned with FOLL_PIN gups
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
@ 2022-02-07  6:22 ` John Hubbard
  2022-02-07  6:22 ` [PATCH v5 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup John Hubbard
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard,
	Christoph Hellwig

From: Peter Xu <peterx@redhat.com>

Alex reported invalid page pointer returned with pin_user_pages_remote()
from vfio after upstream commit 4b6c33b32296 ("vfio/type1: Prepare for
batched pinning with struct vfio_batch").

It turns out that it's not the fault of the vfio commit; however after
vfio switches to a full page buffer to store the page pointers it starts
to expose the problem easier.

The problem is for VM_PFNMAP vmas we should normally fail with an
-EFAULT then vfio will carry on to handle the MMIO regions.  However
when the bug triggered, follow_page_mask() returned -EEXIST for such a
page, which will jump over the current page, leaving that entry in
**pages untouched.  However the caller is not aware of it, hence the
caller will reference the page as usual even if the pointer data can be
anything.

We had that -EEXIST logic since commit 1027e4436b6a ("mm: make GUP
handle pfn mapping unless FOLL_GET is requested") which seems very
reasonable.  It could be that when we reworked GUP with FOLL_PIN we
could have overlooked that special path in commit 3faa52c03f44 ("mm/gup:
track FOLL_PIN pages"), even if that commit rightfully touched up
follow_devmap_pud() on checking FOLL_PIN when it needs to return an
-EEXIST.

Attaching the Fixes to the FOLL_PIN rework commit, as it happened later
than 1027e4436b6a.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Debugged-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
[jhubbard: added some tags, removed a reference to an out of tree
           module, and reflowed to 72 columns.]
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 mm/gup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index a9d4d724aef7..80229ecf0114 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -465,7 +465,7 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
 		pte_t *pte, unsigned int flags)
 {
 	/* No page to get reference */
-	if (flags & FOLL_GET)
+	if (flags & (FOLL_GET | FOLL_PIN))
 		return -EFAULT;
 
 	if (flags & FOLL_TOUCH) {
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH v5 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
  2022-02-07  6:22 ` [PATCH v5 1/5] mm: Fix invalid page pointer returned with FOLL_PIN gups John Hubbard
@ 2022-02-07  6:22 ` John Hubbard
  2022-02-07  6:22 ` [PATCH v5 3/5] mm/gup: remove unused pin_user_pages_locked() John Hubbard
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard,
	Christoph Hellwig, Jason Gunthorpe

Remove a quirky special case from follow_pfn_pte(), and adjust its
callers to match. Caller changes include:

__get_user_pages(): Regardless of any FOLL_* flags, get_user_pages() and
its variants should handle PFN-only entries by stopping early, if the
caller expected **pages to be filled in. This makes for a more reliable
API, as compared to the previous approach of skipping over such entries
(and thus leaving them silently unwritten).

move_pages(): squash the -EEXIST error return from follow_page() into
-EFAULT, because -EFAULT is listed in the man page, whereas -EEXIST is
not.

Cc: Peter Xu <peterx@redhat.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 mm/gup.c     | 13 ++++++++-----
 mm/migrate.c |  7 +++++++
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 80229ecf0114..2df0d0103c43 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -464,10 +464,6 @@ static struct page *no_page_table(struct vm_area_struct *vma,
 static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
 		pte_t *pte, unsigned int flags)
 {
-	/* No page to get reference */
-	if (flags & (FOLL_GET | FOLL_PIN))
-		return -EFAULT;
-
 	if (flags & FOLL_TOUCH) {
 		pte_t entry = *pte;
 
@@ -1205,8 +1201,15 @@ static long __get_user_pages(struct mm_struct *mm,
 		} else if (PTR_ERR(page) == -EEXIST) {
 			/*
 			 * Proper page table entry exists, but no corresponding
-			 * struct page.
+			 * struct page. If the caller expects **pages to be
+			 * filled in, bail out now, because that can't be done
+			 * for this page.
 			 */
+			if (pages) {
+				ret = PTR_ERR(page);
+				goto out;
+			}
+
 			goto next_page;
 		} else if (IS_ERR(page)) {
 			ret = PTR_ERR(page);
diff --git a/mm/migrate.c b/mm/migrate.c
index c7da064b4781..be0d5ae36dc1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1761,6 +1761,13 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
 			continue;
 		}
 
+		/*
+		 * The move_pages() man page does not have an -EEXIST choice, so
+		 * use -EFAULT instead.
+		 */
+		if (err == -EEXIST)
+			err = -EFAULT;
+
 		/*
 		 * If the page is already on the target node (!err), store the
 		 * node, otherwise, store the err.
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH v5 3/5] mm/gup: remove unused pin_user_pages_locked()
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
  2022-02-07  6:22 ` [PATCH v5 1/5] mm: Fix invalid page pointer returned with FOLL_PIN gups John Hubbard
  2022-02-07  6:22 ` [PATCH v5 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup John Hubbard
@ 2022-02-07  6:22 ` John Hubbard
  2022-02-07  6:22 ` [PATCH v5 4/5] mm: change lookup_node() to use get_user_pages_fast() John Hubbard
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard,
	Jason Gunthorpe, Christoph Hellwig

This routine was used for a short while, but then the calling code was
refactored and the only caller was removed.

Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 include/linux/mm.h |  2 --
 mm/gup.c           | 29 -----------------------------
 2 files changed, 31 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 213cc569b192..80c540c17d83 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1918,8 +1918,6 @@ long pin_user_pages(unsigned long start, unsigned long nr_pages,
 		    struct vm_area_struct **vmas);
 long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
 		    unsigned int gup_flags, struct page **pages, int *locked);
-long pin_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,
diff --git a/mm/gup.c b/mm/gup.c
index 2df0d0103c43..6664dfa7a38f 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3146,32 +3146,3 @@ long pin_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
 	return get_user_pages_unlocked(start, nr_pages, pages, gup_flags);
 }
 EXPORT_SYMBOL(pin_user_pages_unlocked);
-
-/*
- * pin_user_pages_locked() is the FOLL_PIN variant of get_user_pages_locked().
- * Behavior is the same, except that this one sets FOLL_PIN and rejects
- * FOLL_GET.
- */
-long pin_user_pages_locked(unsigned long start, unsigned long nr_pages,
-			   unsigned int gup_flags, struct page **pages,
-			   int *locked)
-{
-	/*
-	 * FIXME: Current FOLL_LONGTERM behavior is incompatible with
-	 * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
-	 * vmas.  As there are no users of this flag in this call we simply
-	 * disallow this option for now.
-	 */
-	if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
-		return -EINVAL;
-
-	/* 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_locked(current->mm, start, nr_pages,
-				       pages, NULL, locked,
-				       gup_flags | FOLL_TOUCH);
-}
-EXPORT_SYMBOL(pin_user_pages_locked);
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH v5 4/5] mm: change lookup_node() to use get_user_pages_fast()
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
                   ` (2 preceding siblings ...)
  2022-02-07  6:22 ` [PATCH v5 3/5] mm/gup: remove unused pin_user_pages_locked() John Hubbard
@ 2022-02-07  6:22 ` John Hubbard
  2022-02-07  6:22 ` [PATCH v5 5/5] mm/gup: remove unused get_user_pages_locked() John Hubbard
  2022-02-12  0:24 ` [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
  5 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard,
	Christoph Hellwig, Jason Gunthorpe

The purpose of calling get_user_pages_locked() from lookup_node() was to
allow for unlocking the mmap_lock when reading a page from the disk
during a page fault (hidden behind VM_FAULT_RETRY). The idea was to
reduce contention on the heavily-used mmap_lock. (Thanks to Jan Kara for
clearly pointing that out, and in fact I've used some of his wording
here.)

However, it is unlikely for lookup_node() to take a page fault. With
that in mind, change over to calling get_user_pages_fast(). This
simplifies the code, runs a little faster in the expected case, and
allows removing get_user_pages_locked() entirely, in a subsequent patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 mm/mempolicy.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 028e8dd82b44..3f8dc58da3e8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -907,17 +907,14 @@ static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
 static int lookup_node(struct mm_struct *mm, unsigned long addr)
 {
 	struct page *p = NULL;
-	int err;
+	int ret;
 
-	int locked = 1;
-	err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked);
-	if (err > 0) {
-		err = page_to_nid(p);
+	ret = get_user_pages_fast(addr & PAGE_MASK, 1, 0, &p);
+	if (ret > 0) {
+		ret = page_to_nid(p);
 		put_page(p);
 	}
-	if (locked)
-		mmap_read_unlock(mm);
-	return err;
+	return ret;
 }
 
 /* Retrieve NUMA policy */
@@ -968,14 +965,14 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 	if (flags & MPOL_F_NODE) {
 		if (flags & MPOL_F_ADDR) {
 			/*
-			 * Take a refcount on the mpol, lookup_node()
-			 * will drop the mmap_lock, so after calling
-			 * lookup_node() only "pol" remains valid, "vma"
-			 * is stale.
+			 * Take a refcount on the mpol, because we are about to
+			 * drop the mmap_lock, after which only "pol" remains
+			 * valid, "vma" is stale.
 			 */
 			pol_refcount = pol;
 			vma = NULL;
 			mpol_get(pol);
+			mmap_read_unlock(mm);
 			err = lookup_node(mm, addr);
 			if (err < 0)
 				goto out;
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH v5 5/5] mm/gup: remove unused get_user_pages_locked()
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
                   ` (3 preceding siblings ...)
  2022-02-07  6:22 ` [PATCH v5 4/5] mm: change lookup_node() to use get_user_pages_fast() John Hubbard
@ 2022-02-07  6:22 ` John Hubbard
  2022-02-12  0:24 ` [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
  5 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-07  6:22 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm, John Hubbard,
	Christoph Hellwig, Jason Gunthorpe

Now that the last caller of get_user_pages_locked() is gone, remove it.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 include/linux/mm.h |  2 --
 mm/gup.c           | 59 ----------------------------------------------
 2 files changed, 61 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80c540c17d83..528ef1cb4f3a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1916,8 +1916,6 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
 long pin_user_pages(unsigned long start, unsigned long nr_pages,
 		    unsigned int gup_flags, struct page **pages,
 		    struct vm_area_struct **vmas);
-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,
diff --git a/mm/gup.c b/mm/gup.c
index 6664dfa7a38f..7337520afa49 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2145,65 +2145,6 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
 }
 EXPORT_SYMBOL(get_user_pages);
 
-/**
- * get_user_pages_locked() - variant of get_user_pages()
- *
- * @start:      starting user address
- * @nr_pages:   number of pages from start to pin
- * @gup_flags:  flags modifying lookup behaviour
- * @pages:      array that receives pointers to the pages pinned.
- *              Should be at least nr_pages long. Or NULL, if caller
- *              only intends to ensure the pages are faulted in.
- * @locked:     pointer to lock flag indicating whether lock is held and
- *              subsequently whether VM_FAULT_RETRY functionality can be
- *              utilised. Lock must initially be held.
- *
- * It is suitable to replace the form:
- *
- *      mmap_read_lock(mm);
- *      do_something()
- *      get_user_pages(mm, ..., pages, NULL);
- *      mmap_read_unlock(mm);
- *
- *  to:
- *
- *      int locked = 1;
- *      mmap_read_lock(mm);
- *      do_something()
- *      get_user_pages_locked(mm, ..., pages, &locked);
- *      if (locked)
- *          mmap_read_unlock(mm);
- *
- * We can leverage the VM_FAULT_RETRY functionality in the page fault
- * paths better by using either get_user_pages_locked() or
- * get_user_pages_unlocked().
- *
- */
-long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
-			   unsigned int gup_flags, struct page **pages,
-			   int *locked)
-{
-	/*
-	 * FIXME: Current FOLL_LONGTERM behavior is incompatible with
-	 * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
-	 * vmas.  As there are no users of this flag in this call we simply
-	 * disallow this option for now.
-	 */
-	if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
-		return -EINVAL;
-	/*
-	 * FOLL_PIN must only be set internally by the pin_user_pages*() APIs,
-	 * never directly by the caller, so enforce that:
-	 */
-	if (WARN_ON_ONCE(gup_flags & FOLL_PIN))
-		return -EINVAL;
-
-	return __get_user_pages_locked(current->mm, start, nr_pages,
-				       pages, NULL, locked,
-				       gup_flags | FOLL_TOUCH);
-}
-EXPORT_SYMBOL(get_user_pages_locked);
-
 /*
  * get_user_pages_unlocked() is suitable to replace the form:
  *
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [PATCH v5 0/5] mm/gup: some cleanups
  2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
                   ` (4 preceding siblings ...)
  2022-02-07  6:22 ` [PATCH v5 5/5] mm/gup: remove unused get_user_pages_locked() John Hubbard
@ 2022-02-12  0:24 ` John Hubbard
  2022-02-12  0:27   ` Andrew Morton
  5 siblings, 1 reply; 9+ messages in thread
From: John Hubbard @ 2022-02-12  0:24 UTC (permalink / raw)
  To: Andrew Morton, Peter Xu, Jason Gunthorpe
  Cc: David Hildenbrand, Lukas Bulwahn, Claudio Imbrenda,
	Christoph Hellwig, Matthew Wilcox, Jan Kara, Kirill A . Shutemov,
	Alex Williamson, Andrea Arcangeli, LKML, linux-mm

On 2/6/22 22:22, John Hubbard wrote:
> Hi,
> 
> Here's an update, mainly just collecting reviewed-by tags:
> 
> Changes since v4:
> 
>      * Patch 1: reflowed the commit description to 72 columns.
> 
>      * Added reviewed-by's from Christoph and Jan for remaining patches.
> 
>      * Rebased onto 5.17-rc3.
> 

Hi Andrew,

Is this OK to put in mmotm yet? All the patches here have been reviewed.
And this small series also does not conflict with Willy's "[PATCH 00/75]
MM folio patches for 5.18" series.


thanks,
John Hubbard

> 
> Changes since v3:
> 
>      * Patch 1: Commit log: removed a reference to an out of tree module,
>        and updated tags and added a short note to that effect.
> 
>      * Patch 2: Fixed up do_move_pages(), to squash -EEXIST returns from
>        follow_page() into something that move_pages() allows: -EFAULT.
>        This is from reviews by Jan Kara, Matthew Wilcox, Jason Gunthorpe.
> 
>        Removed all Reviewed-by tags for this patch, due to that update.
> 
>      * Patch 4: Split into two patches, as recommended by Christoph
>        Hellwig. Left the Reviewed-by tags intact because no code changes
>        were required.
> 
>      * Added Reviewed-by tags from Claudio Imbrenda.
> 
> Changes since v2:
> 
>      * Patch 2: Removed an unnecessary line that was causing a
>        clang-analyzer complaint, as reported by Lukas Bulwahn
>        [1] (thanks!), and retested locally.
> 
>        Jason: I've boldly left your Reviewed-by tag on this patch,
>        because I am predicting you'll agree with it...
> 
>      * Added Reviewed-by tags from Jan Kara, Christoph Hellwig, and
>        Jason Gunthorpe that have collected since v2.
> 
> 
> Changes since v1:
>      * Patch 4: changed from get_user_pages(), to get_user_pages_fast().
> 
>      * Patch 4: Rewrote the commit description--thanks to Jan Kara for
>                 that feedback.
> 
>      * Patch 1: Removed Jerome's Cc from patch 1, due to a stale email
>                 address.
> 
>      * Added Reviewed-by's from David Hildenbrand and Jason Gunthorpe.
> 
> Original cover letter, updated as necessary:
> 
> I'm including Peter's patch as the first one in this tiny series. (The
> commit description has my r-b tag in place of my Cc, and removes
> Jerome's Cc because he is no longer at redhat.com) The second patch is
> what I had in mind for a follow-up to that, when we were discussing that
> fix [2].
> 
> Plus, a couple more small removals that I had queued up:
> 
> The third patch removes a completely unused routine:
> pin_user_pages_locked().
> 
> The forth patch removes a similar routine, get_user_pages_locked(), that
> only has one caller. It now calls get_user_pages_fast(), instead.
> 
> v1 of this patchset is here:
> https://lore.kernel.org/all/20220131051752.447699-1-jhubbard@nvidia.com/
> 
> v2:
> https://lore.kernel.org/r/20220201101108.306062-1-jhubbard@nvidia.com
> 
> v3:
> https://lore.kernel.org/r/20220203093232.572380-1-jhubbard@nvidia.com
> 
> v4:
> https://lore.kernel.org/r/20220204020010.68930-1-jhubbard@nvidia.com
> 
> 
> [1] https://lore.kernel.org/r/CAKXUXMxFK9bo8jDoRZbQ0r2j-JwAGg3Xc5cpAcLaHfwHddJ7ew@mail.gmail.com
> 
> [2] https://lore.kernel.org/all/20220125033700.69705-1-peterx@redhat.com/
> 
> 
> John Hubbard (4):
>    mm/gup: follow_pfn_pte(): -EEXIST cleanup
>    mm/gup: remove unused pin_user_pages_locked()
>    mm: change lookup_node() to use get_user_pages_fast()
>    mm/gup: remove unused get_user_pages_locked()
> 
> Peter Xu (1):
>    mm: Fix invalid page pointer returned with FOLL_PIN gups
> 
>   include/linux/mm.h |   4 --
>   mm/gup.c           | 101 ++++-----------------------------------------
>   mm/mempolicy.c     |  21 ++++------
>   mm/migrate.c       |   7 ++++
>   4 files changed, 24 insertions(+), 109 deletions(-)
> 
> 
> base-commit: dfd42facf1e4ada021b939b4e19c935dcdd55566



^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v5 0/5] mm/gup: some cleanups
  2022-02-12  0:24 ` [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
@ 2022-02-12  0:27   ` Andrew Morton
  2022-02-12  0:30     ` John Hubbard
  0 siblings, 1 reply; 9+ messages in thread
From: Andrew Morton @ 2022-02-12  0:27 UTC (permalink / raw)
  To: John Hubbard
  Cc: Peter Xu, Jason Gunthorpe, David Hildenbrand, Lukas Bulwahn,
	Claudio Imbrenda, Christoph Hellwig, Matthew Wilcox, Jan Kara,
	Kirill A . Shutemov, Alex Williamson, Andrea Arcangeli, LKML,
	linux-mm

On Fri, 11 Feb 2022 16:24:15 -0800 John Hubbard <jhubbard@nvidia.com> wrote:

> On 2/6/22 22:22, John Hubbard wrote:
> > Hi,
> > 
> > Here's an update, mainly just collecting reviewed-by tags:
> > 
> > Changes since v4:
> > 
> >      * Patch 1: reflowed the commit description to 72 columns.
> > 
> >      * Added reviewed-by's from Christoph and Jan for remaining patches.
> > 
> >      * Rebased onto 5.17-rc3.
> > 
> 
> Hi Andrew,
> 
> Is this OK to put in mmotm yet? All the patches here have been reviewed.
> And this small series also does not conflict with Willy's "[PATCH 00/75]
> MM folio patches for 5.18" series.

The v4 series is is -mm.  Shall update to v5 soon...


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v5 0/5] mm/gup: some cleanups
  2022-02-12  0:27   ` Andrew Morton
@ 2022-02-12  0:30     ` John Hubbard
  0 siblings, 0 replies; 9+ messages in thread
From: John Hubbard @ 2022-02-12  0:30 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Peter Xu, Jason Gunthorpe, David Hildenbrand, Lukas Bulwahn,
	Claudio Imbrenda, Christoph Hellwig, Matthew Wilcox, Jan Kara,
	Kirill A . Shutemov, Alex Williamson, Andrea Arcangeli, LKML,
	linux-mm

On 2/11/22 16:27, Andrew Morton wrote:
...
>> Hi Andrew,
>>
>> Is this OK to put in mmotm yet? All the patches here have been reviewed.
>> And this small series also does not conflict with Willy's "[PATCH 00/75]
>> MM folio patches for 5.18" series.
> 
> The v4 series is is -mm.  Shall update to v5 soon...

Oh, sorry for the noise, then. Somehow I did not see the usual notification
emails this time around, I'm not sure what happened there.

thanks,
-- 
John Hubbard
NVIDIA


^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2022-02-12  0:30 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-07  6:22 [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
2022-02-07  6:22 ` [PATCH v5 1/5] mm: Fix invalid page pointer returned with FOLL_PIN gups John Hubbard
2022-02-07  6:22 ` [PATCH v5 2/5] mm/gup: follow_pfn_pte(): -EEXIST cleanup John Hubbard
2022-02-07  6:22 ` [PATCH v5 3/5] mm/gup: remove unused pin_user_pages_locked() John Hubbard
2022-02-07  6:22 ` [PATCH v5 4/5] mm: change lookup_node() to use get_user_pages_fast() John Hubbard
2022-02-07  6:22 ` [PATCH v5 5/5] mm/gup: remove unused get_user_pages_locked() John Hubbard
2022-02-12  0:24 ` [PATCH v5 0/5] mm/gup: some cleanups John Hubbard
2022-02-12  0:27   ` Andrew Morton
2022-02-12  0:30     ` John Hubbard

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