[out of topic] Cc list is edited to quite mail agent warning:
-"Dr. David Alan Gilbert"@v2.random; " <dgilbert@xxxxxxxxxx>
+"Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
-Pavel Emelyanov <xemul@xxxxxxxxxxxxx>"@v2.random
+Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
-Michael Rapoport <RAPOPORT@xxxxxxxxxx>
+Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
On Thursday, November 03, 2016 3:34 AM Andrea Arcangeli wrote:
> +
> +#ifdef CONFIG_HUGETLB_PAGE
> +/*
> + * __mcopy_atomic processing for HUGETLB vmas. Note that this routine is
> + * called with mmap_sem held, it will release mmap_sem before returning.
> + */
> +static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
> + struct vm_area_struct *dst_vma,
> + unsigned long dst_start,
> + unsigned long src_start,
> + unsigned long len,
> + bool zeropage)
> +{
> + ssize_t err;
> + pte_t *dst_pte;
> + unsigned long src_addr, dst_addr;
> + long copied;
> + struct page *page;
> + struct hstate *h;
> + unsigned long vma_hpagesize;
> + pgoff_t idx;
> + u32 hash;
> + struct address_space *mapping;
> +
> + /*
> + * There is no default zero huge page for all huge page sizes as
> + * supported by hugetlb. A PMD_SIZE huge pages may exist as used
> + * by THP. Since we can not reliably insert a zero page, this
> + * feature is not supported.
> + */
> + if (zeropage)
> + return -EINVAL;
Release mmap_sem before return?
> +
> + src_addr = src_start;
> + dst_addr = dst_start;
> + copied = 0;
> + page = NULL;
> + vma_hpagesize = vma_kernel_pagesize(dst_vma);
> +
> +retry:
> + /*
> + * On routine entry dst_vma is set. If we had to drop mmap_sem and
> + * retry, dst_vma will be set to NULL and we must lookup again.
> + */
> + err = -EINVAL;
> + if (!dst_vma) {
> + dst_vma = find_vma(dst_mm, dst_start);
In case of retry, s/dst_start/dst_addr/?
And check if we find a valid vma?
> @@ -182,6 +355,13 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
> goto out_unlock;
>
> /*
> + * If this is a HUGETLB vma, pass off to appropriate routine
> + */
> + if (dst_vma->vm_flags & VM_HUGETLB)
> + return __mcopy_atomic_hugetlb(dst_mm, dst_vma, dst_start,
> + src_start, len, false);
Use is_vm_hugetlb_page()?
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