| Message ID | 20201215141300.1436976-1-Liam.Howlett@Oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/mmap: Don't unlock VMAs in remap_file_pages() | expand |
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.
* 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
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);
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(-)