+ mm-mremap-simplify-vma-expansion-again.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/mremap: simplify vma expansion again
has been added to the -mm mm-unstable branch.  Its filename is
     mm-mremap-simplify-vma-expansion-again.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mremap-simplify-vma-expansion-again.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Vlastimil Babka <vbabka@suse.cz>
Subject: mm/mremap: simplify vma expansion again
Date: Thu, 9 Mar 2023 12:12:58 +0100

This effectively reverts d014cd7c1c35 ("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>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mremap.c |   20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

--- a/mm/mremap.c~mm-mremap-simplify-vma-expansion-again
+++ a/mm/mremap.c
@@ -1041,23 +1041,11 @@ SYSCALL_DEFINE5(mremap, unsigned long, a
 			 * 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;
_

Patches currently in -mm which might be from vbabka@suse.cz are

mm-page_alloc-reduce-page-alloc-free-sanity-checks.patch
mm-mmap-vma_merge-use-only-primary-pointers-for-preparing-merge.patch
mm-mmap-vma_merge-use-the-proper-vma-pointer-in-case-3.patch
mm-mmap-vma_merge-use-the-proper-vma-pointers-in-cases-1-and-6.patch
mm-mmap-vma_merge-use-the-proper-vma-pointer-in-case-4.patch
mm-mmap-vma_merge-initialize-mid-and-next-in-natural-order.patch
mm-mmap-vma_merge-set-mid-to-null-if-not-applicable.patch
mm-mmap-vma_merge-rename-adj_next-to-adj_start.patch
mm-mmap-vma_merge-convert-mergeability-checks-to-return-bool.patch
mm-mmap-start-distinguishing-if-vma-can-be-removed-in-mergeability-test.patch
mm-mremap-simplify-vma-expansion-again.patch