mm: vma_adjust: remove superfluous confusing update in remove_next == 1 case
mm->highest_vm_end doesn't need any update. After finally removing the oddness from vma_merge case 8 that was causing: 1) constant risk of trouble whenever anybody would check vma fields from rmap_walks, like it happened when page migration was introduced and it read the vma->vm_page_prot from a rmap_walk 2) the callers of vma_merge to re-initialize any value different from the current vma, instead of vma_merge() more reliably returning a vma that already matches all fields passed as parameter .. it is also worth to take the opportunity of cleaning up superfluous code in vma_adjust(), that if not removed adds up to the hard readability of the function. Link: http://lkml.kernel.org/r/1474492522-2261-5-git-send-email-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Vorlicek <janvorli@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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mm/mmap.c
24
mm/mmap.c
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@ -817,8 +817,28 @@ again:
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}
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}
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else if (next)
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else if (next)
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vma_gap_update(next);
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vma_gap_update(next);
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else
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else {
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mm->highest_vm_end = end;
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/*
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* If remove_next == 2 we obviously can't
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* reach this path.
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*
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* If remove_next == 3 we can't reach this
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* path because pre-swap() next is always not
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* NULL. pre-swap() "next" is not being
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* removed and its next->vm_end is not altered
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* (and furthermore "end" already matches
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* next->vm_end in remove_next == 3).
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*
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* We reach this only in the remove_next == 1
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* case if the "next" vma that was removed was
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* the highest vma of the mm. However in such
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* case next->vm_end == "end" and the extended
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* "vma" has vma->vm_end == next->vm_end so
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* mm->highest_vm_end doesn't need any update
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* in remove_next == 1 case.
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*/
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VM_WARN_ON(mm->highest_vm_end != end);
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}
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}
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}
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if (insert && file)
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if (insert && file)
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uprobe_mmap(insert);
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uprobe_mmap(insert);
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