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| author | Brian Geffon <bgeffon@google.com> | 2021-04-30 07:57:48 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-30 20:20:39 +0200 |
| commit | 14d071134c740cfe61c09fc506fd3ab052beea10 (patch) | |
| tree | d5ef569e0bf6d6d0f701ef5c7abb95fdf56d7757 /mm/mmap.c | |
| parent | mm: extend MREMAP_DONTUNMAP to non-anonymous mappings (diff) | |
| download | linux-14d071134c740cfe61c09fc506fd3ab052beea10.tar.xz linux-14d071134c740cfe61c09fc506fd3ab052beea10.zip | |
Revert "mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio"
This reverts commit cd544fd1dc9293c6702fab6effa63dac1cc67e99.
As discussed in [1] this commit was a no-op because the mapping type was
checked in vma_to_resize before move_vma is ever called. This meant that
vm_ops->mremap() would never be called on such mappings. Furthermore,
we've since expanded support of MREMAP_DONTUNMAP to non-anonymous
mappings, and these special mappings are still protected by the existing
check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL.
1. https://lkml.org/lkml/2020/12/28/2340
Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sonny Rao <sonnyrao@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 1d96a21acb2f..347ef9b83bb5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3409,14 +3409,10 @@ static const char *special_mapping_name(struct vm_area_struct *vma) return ((struct vm_special_mapping *)vma->vm_private_data)->name; } -static int special_mapping_mremap(struct vm_area_struct *new_vma, - unsigned long flags) +static int special_mapping_mremap(struct vm_area_struct *new_vma) { struct vm_special_mapping *sm = new_vma->vm_private_data; - if (flags & MREMAP_DONTUNMAP) - return -EINVAL; - if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) return -EFAULT; |