mm/mmap: mmap_region() fixes for when expanding vma as well as anon

When expanding a vma, call khugepaged_enter_vma_merge() with correct vma.

Also, set the vm_pgoff to the correct value when adding an anon mapping.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/mm/mmap.c b/mm/mmap.c
index 81eda5e3c1e3312f380fc2b39ac3bdf5e95f832c..10d71be99816f51391e373c2af7d9ff90a275ed1 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2537,6 +2537,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        struct ma_state ma_prev, tmp;
        MA_STATE(mas, &mm->mm_mt, addr, end - 1);
 
+       validate_mm(mm);
+
        /* Check against address space limit. */
        if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
                unsigned long nr_pages;
@@ -2583,6 +2585,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
                if (next->vm_start == end && vma_policy(next) &&
                    can_vma_merge_before(next, vm_flags, NULL, file,
                                         pgoff + pglen, NULL_VM_UFFD_CTX)) {
+                       /* Try to expand next back over the requested area */
                        merge_end = next->vm_end;
                        vma = next;
                        vm_pgoff = next->vm_pgoff - pglen;
@@ -2595,17 +2598,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        if (prev && prev->vm_end == addr && !vma_policy(prev) &&
            can_vma_merge_after(prev, vm_flags, NULL, file, pgoff,
                                NULL_VM_UFFD_CTX)) {
+               /* Try to expand the prev over the requested area */
                merge_start = prev->vm_start;
                vma = prev;
                tmp = ma_prev;
                vm_pgoff = prev->vm_pgoff;
        }
 
-
        /* Actually expand, if possible */
        if (vma &&
            !vma_expand(&tmp, vma, merge_start, merge_end, vm_pgoff, next)) {
-               khugepaged_enter_vma_merge(prev, vm_flags);
+               khugepaged_enter_vma_merge(vma, vm_flags);
                goto expanded;
        }
 
@@ -2693,6 +2696,7 @@ cannot_expand:
                        goto free_vma;
        } else {
                vma_set_anonymous(vma);
+               vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
        }
 
        /* Allow architectures to sanity-check the vm_flags */
@@ -2747,6 +2751,7 @@ expanded:
 
        vma_set_page_prot(vma);
 
+       validate_mm(mm);
        return addr;
 
 unmap_and_free_vma: