7:22 p.m.
On 04/07/2015 12:03 PM, Kirill A. Shutemov wrote:
On Tue, Apr 07, 2015 at 11:40:06AM +0300, Boaz Harrosh wrote:
>
> [v2]
> Based on linux-next/akpm [3dc4623]. For v4.1 merge window
> Incorporated comments from Andrew And Kirill
Not really. You've ignored most of them. See below.
Yes sorry about that I sent the wrong version.
<>
> ---
> include/linux/mm.h | 3 +++
> mm/memory.c | 35 +++++++++++++++++++++++++++++++----
Please, document it in Documentation/filesystems/Locking.
Ha, I missed this one. Ok will try to put something coherent.
<>
> diff --git a/mm/memory.c b/mm/memory.c
> index 59f6268..6e8f3f6 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1982,6 +1982,19 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct
page *page,
> return ret;
> }
>
> +static int do_pfn_mkwrite(struct vm_area_struct *vma, unsigned long address)
> +{
> + struct vm_fault vmf = {
> + .page = 0,
.page = NULL,
> + .pgoff = (((address & PAGE_MASK) - vma->vm_start)
> + >> PAGE_SHIFT) + vma->vm_pgoff,
.pgoff = linear_page_index(vma, address),
Yes I had fixes for these two
> + .virtual_address = (void __user *)(address & PAGE_MASK),
> + .flags = FAULT_FLAG_WRITE | FAULT_FLAG_MKWRITE,
> + };
> +
> + return vma->vm_ops->pfn_mkwrite(vma, &vmf);
> +}
> +
> /*
> * Handle write page faults for pages that can be reused in the current vma
> *
> @@ -2259,14 +2272,28 @@ static int do_wp_page(struct mm_struct *mm, struct
vm_area_struct *vma,
> * VM_PFNMAP VMA.
> *
> * We should not cow pages in a shared writeable mapping.
> - * Just mark the pages writable as we can't do any dirty
> - * accounting on raw pfn maps.
> + * Just mark the pages writable and/or call ops->pfn_mkwrite.
> */
> if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
> - (VM_WRITE|VM_SHARED))
> + (VM_WRITE|VM_SHARED)) {
Let's move this case in separate function -- wp_pfn_shared(). As we do for
wp_page_shared().
Ha, OK I will try that. I will need to re-run tests to make sure I did
not mess up
Thanks will fix, makes sense
Boaz
> + if (vma->vm_ops && vma->vm_ops->pfn_mkwrite)
{
> + int ret;
> +
> + pte_unmap_unlock(page_table, ptl);
> + ret = do_pfn_mkwrite(vma, address);
> + if (ret & VM_FAULT_ERROR)
> + return ret;
> + page_table = pte_offset_map_lock(mm, pmd,
> + address, &ptl);
> + /* Did pfn_mkwrite already fixed up the pte */
> + if (!pte_same(*page_table, orig_pte)) {
> + pte_unmap_unlock(page_table, ptl);
> + return ret;
> + }
> + }
> return wp_page_reuse(mm, vma, address, page_table, ptl,
> orig_pte, old_page, 0, 0);
> -
> + }
> pte_unmap_unlock(page_table, ptl);
> return wp_page_copy(mm, vma, address, page_table, pmd,
> orig_pte, old_page);