On 14/11/18 22:51, Barret Rhoden wrote:
> KVM has a use case for determining the size of a dax mapping. The KVM
> code has easy access to the address and the mm; hence the change in
> parameters.
>
> Signed-off-by: Barret Rhoden <brho@xxxxxxxxxx>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
> include/linux/mm.h | 3 +++
> mm/memory-failure.c | 38 +++-----------------------------------
> mm/util.c | 34 ++++++++++++++++++++++++++++++++++
> 3 files changed, 40 insertions(+), 35 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5411de93a363..51215d695753 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -935,6 +935,9 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
> }
> #endif /* CONFIG_DEV_PAGEMAP_OPS */
>
> +unsigned long dev_pagemap_mapping_shift(unsigned long address,
> + struct mm_struct *mm);
> +
> static inline void get_page(struct page *page)
> {
> page = compound_head(page);
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 0cd3de3550f0..c3f2c6a8607e 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -265,40 +265,6 @@ void shake_page(struct page *p, int access)
> }
> EXPORT_SYMBOL_GPL(shake_page);
>
> -static unsigned long dev_pagemap_mapping_shift(struct page *page,
> - struct vm_area_struct *vma)
> -{
> - unsigned long address = vma_address(page, vma);
> - pgd_t *pgd;
> - p4d_t *p4d;
> - pud_t *pud;
> - pmd_t *pmd;
> - pte_t *pte;
> -
> - pgd = pgd_offset(vma->vm_mm, address);
> - if (!pgd_present(*pgd))
> - return 0;
> - p4d = p4d_offset(pgd, address);
> - if (!p4d_present(*p4d))
> - return 0;
> - pud = pud_offset(p4d, address);
> - if (!pud_present(*pud))
> - return 0;
> - if (pud_devmap(*pud))
> - return PUD_SHIFT;
> - pmd = pmd_offset(pud, address);
> - if (!pmd_present(*pmd))
> - return 0;
> - if (pmd_devmap(*pmd))
> - return PMD_SHIFT;
> - pte = pte_offset_map(pmd, address);
> - if (!pte_present(*pte))
> - return 0;
> - if (pte_devmap(*pte))
> - return PAGE_SHIFT;
> - return 0;
> -}
> -
> /*
> * Failure handling: if we can't find or can't kill a process there's
> * not much we can do. We just print a message and ignore otherwise.
> @@ -329,7 +295,9 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
> tk->addr = page_address_in_vma(p, vma);
> tk->addr_valid = 1;
> if (is_zone_device_page(p))
> - tk->size_shift = dev_pagemap_mapping_shift(p, vma);
> + tk->size_shift =
> + dev_pagemap_mapping_shift(vma_address(page, vma),
> + vma->vm_mm);
> else
> tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT;
>
> diff --git a/mm/util.c b/mm/util.c
> index 8bf08b5b5760..61bc9bab931d 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -780,3 +780,37 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen)
> out:
> return res;
> }
> +
> +unsigned long dev_pagemap_mapping_shift(unsigned long address,
> + struct mm_struct *mm)
> +{
> + pgd_t *pgd;
> + p4d_t *p4d;
> + pud_t *pud;
> + pmd_t *pmd;
> + pte_t *pte;
> +
> + pgd = pgd_offset(mm, address);
> + if (!pgd_present(*pgd))
> + return 0;
> + p4d = p4d_offset(pgd, address);
> + if (!p4d_present(*p4d))
> + return 0;
> + pud = pud_offset(p4d, address);
> + if (!pud_present(*pud))
> + return 0;
> + if (pud_devmap(*pud))
> + return PUD_SHIFT;
> + pmd = pmd_offset(pud, address);
> + if (!pmd_present(*pmd))
> + return 0;
> + if (pmd_devmap(*pmd))
> + return PMD_SHIFT;
> + pte = pte_offset_map(pmd, address);
> + if (!pte_present(*pte))
> + return 0;
> + if (pte_devmap(*pte))
> + return PAGE_SHIFT;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(dev_pagemap_mapping_shift);
>
Andrew,
can you ack this patch?
Thanks,
Paolo
