* [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages()
@ 2020-12-15 14:13 Liam R. Howlett
2020-12-15 14:50 ` Matthew Wilcox
0 siblings, 1 reply; 3+ messages in thread
From: Liam R. Howlett @ 2020-12-15 14:13 UTC (permalink / raw)
To: linux-mm, linux-kernel; +Cc: Andrew Morton
do_mmap() will unlock the necessary VMAs. There is also a bug in the
loop which will evaluate as false and not unlock any VMAs anyways.
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
mm/mmap.c | 19 -------------------
1 file changed, 19 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 5c8b4485860de..008adf20611e5 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3025,25 +3025,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
flags &= MAP_NONBLOCK;
flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
- if (vma->vm_flags & VM_LOCKED) {
- struct vm_area_struct *tmp;
- flags |= MAP_LOCKED;
-
- /* drop PG_Mlocked flag for over-mapped range */
- for (tmp = vma; tmp->vm_start >= start + size;
- tmp = tmp->vm_next) {
- /*
- * Split pmd and munlock page on the border
- * of the range.
- */
- vma_adjust_trans_huge(tmp, start, start + size, 0);
-
- munlock_vma_pages_range(tmp,
- max(tmp->vm_start, start),
- min(tmp->vm_end, start + size));
- }
- }
-
file = get_file(vma->vm_file);
ret = do_mmap(vma->vm_file, start, size,
prot, flags, pgoff, &populate, NULL);
--
2.28.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages()
2020-12-15 14:13 [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages() Liam R. Howlett
@ 2020-12-15 14:50 ` Matthew Wilcox
2020-12-15 15:40 ` Liam R. Howlett
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Wilcox @ 2020-12-15 14:50 UTC (permalink / raw)
To: Liam R. Howlett; +Cc: linux-mm, linux-kernel, Andrew Morton
On Tue, Dec 15, 2020 at 09:13:00AM -0500, Liam R. Howlett wrote:
> @@ -3025,25 +3025,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
>
> flags &= MAP_NONBLOCK;
> flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
> - if (vma->vm_flags & VM_LOCKED) {
> - struct vm_area_struct *tmp;
> - flags |= MAP_LOCKED;
I think you need to keep ^^^ that line because the vma needs to stay
mlocked.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages()
2020-12-15 14:50 ` Matthew Wilcox
@ 2020-12-15 15:40 ` Liam R. Howlett
0 siblings, 0 replies; 3+ messages in thread
From: Liam R. Howlett @ 2020-12-15 15:40 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: linux-mm, linux-kernel, Andrew Morton
* Matthew Wilcox <willy@infradead.org> [201215 09:50]:
> On Tue, Dec 15, 2020 at 09:13:00AM -0500, Liam R. Howlett wrote:
> > @@ -3025,25 +3025,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
> >
> > flags &= MAP_NONBLOCK;
> > flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE;
> > - if (vma->vm_flags & VM_LOCKED) {
> > - struct vm_area_struct *tmp;
> > - flags |= MAP_LOCKED;
>
> I think you need to keep ^^^ that line because the vma needs to stay
> mlocked.
>
Yes. I missed that this is transferred through by calc_vm_flag_bits()
in do_mmap(). I will revise the patch.
Thanks,
Liam
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-12-15 15:42 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-15 14:13 [PATCH] mm/mmap: Don't unlock VMAs in remap_file_pages() Liam R. Howlett
2020-12-15 14:50 ` Matthew Wilcox
2020-12-15 15:40 ` Liam R. Howlett
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).