Also available in git: https://git.kernel.org/vbabka/h/vma_merge_cleanup-v1r1 My initial goal here was to try making the check for vm_ops->close in is_mergeable_vma() only be applied for vma's that would be truly removed as part of the merge (see Patch 10). This would then allow reverting the quick fix d014cd7c1c35 ("mm, mremap: fix mremap() expanding for vma's with vm_ops->close()"). This was successful enough to allow the revert. Checks using can_vma_merge_before() are still pessimistic about possible vma removal, and making them precise would probably complicate the vma_merge() code too much. Liam's recent simplification of vma_merge() and removal of __vma_adjust() was very much helpful in understanding the vma_merge() implementation and especially when vma removals can happen, which is now very obvious. While studing the code, I've found ways to make it hopefully even more easy to follow, so that's the patches 2-9. That made me notice a bug fixed in patch 1, which is already in the mm tree and here just for completeness. Vlastimil Babka (11): mm/mremap: fix dup_anon_vma() in vma_merge() case 4 mm/mmap/vma_merge: use only primary pointers for preparing merge mm/mmap/vma_merge: use the proper vma pointer in case 3 mm/mmap/vma_merge: use the proper vma pointers in cases 1 and 6 mm/mmap/vma_merge: use the proper vma pointer in case 4 mm/mmap/vma_merge: initialize mid and next in natural order mm/mmap/vma_merge: set mid to NULL if not applicable mm/mmap/vma_merge: rename adj_next to adj_start mm/mmap/vma_merge: convert mergeability checks to return bool mm/mmap: start distinguishing if vma can be removed in mergeability test mm/mremap: simplify vma expansion again mm/mmap.c | 130 +++++++++++++++++++++++++++++----------------------- mm/mremap.c | 20 ++------ 2 files changed, 76 insertions(+), 74 deletions(-) -- 2.39.2
