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mm/mremap: simplify vma expansion again

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This effectively reverts d014cd7c1c ("mm, mremap: fix mremap() expanding
for vma's with vm_ops->close()").  After the recent changes, vma_merge()
is able to handle the expansion properly even when the vma being expanded
has a vm_ops->close operation, so we don't need to special case it
anymore.

Link: https://lkml.kernel.org/r/20230309111258.24079-11-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Vlastimil Babka 2023-03-09 12:12:58 +01:00 committed by Andrew Morton
parent 714965ca82
commit 4bfbe371db
1 changed files with 4 additions and 16 deletions
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20
mm/mremap.c
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@ -1040,23 +1040,11 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
* vma (expand operation itself) and possibly also with
* the next vma if it becomes adjacent to the expanded
* vma and otherwise compatible.
*
* However, vma_merge() can currently fail due to
* is_mergeable_vma() check for vm_ops->close (see the
* comment there). Yet this should not prevent vma
* expanding, so perform a simple expand for such vma.
* Ideally the check for close op should be only done
* when a vma would be actually removed due to a merge.
*/
if (!vma->vm_ops || !vma->vm_ops->close) {
vma = vma_merge(&vmi, mm, vma, extension_start,
extension_end, vma->vm_flags, vma->anon_vma,
vma->vm_file, extension_pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
} else if (vma_expand(&vmi, vma, vma->vm_start,
addr + new_len, vma->vm_pgoff, NULL)) {
vma = NULL;
}
vma = vma_merge(&vmi, mm, vma, extension_start,
extension_end, vma->vm_flags, vma->anon_vma,
vma->vm_file, extension_pgoff, vma_policy(vma),
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
if (!vma) {
vm_unacct_memory(pages);
ret = -ENOMEM;