From: Andrew Morton Date: Thu, 17 Sep 2015 23:02:00 +0000 (-0700) Subject: revert "mm: make sure all file VMAs have ->vm_ops set" X-Git-Tag: firefly_0821_release~176^2~1043^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=28c553d0aa0acf02e18f9e008661491a4b996595;p=firefly-linux-kernel-4.4.55.git revert "mm: make sure all file VMAs have ->vm_ops set" Revert commit 6dc296e7df4c "mm: make sure all file VMAs have ->vm_ops set". Will Deacon reports that it "causes some mmap regressions in LTP, which appears to use a MAP_PRIVATE mmap of /dev/zero as a way to get anonymous pages in some of its tests (specifically mmap10 [1])". William Shuman reports Oracle crashes. So revert the patch while we work out what to do. Reported-by: William Shuman Reported-by: Will Deacon Cc: Kirill A. Shutemov Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/mmap.c b/mm/mmap.c index 971dd2cb77d2..c739d6db7193 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -612,8 +612,6 @@ static unsigned long count_vma_pages_range(struct mm_struct *mm, void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, struct rb_node **rb_link, struct rb_node *rb_parent) { - WARN_ONCE(vma->vm_file && !vma->vm_ops, "missing vma->vm_ops"); - /* Update tracking information for the gap following the new vma. */ if (vma->vm_next) vma_gap_update(vma->vm_next); @@ -1638,12 +1636,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr, */ WARN_ON_ONCE(addr != vma->vm_start); - /* All file mapping must have ->vm_ops set */ - if (!vma->vm_ops) { - static const struct vm_operations_struct dummy_ops = {}; - vma->vm_ops = &dummy_ops; - } - addr = vma->vm_start; vm_flags = vma->vm_flags; } else if (vm_flags & VM_SHARED) {