From: Dan Williams <dan.j.williams@xxxxxxxxx> Subject: mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct When device-dax is operating in huge-page mode we want it to behave like hugetlbfs and report the MMU page mapping size that is being enforced by the vma. Similar to commit 31383c6865a5 "mm, hugetlbfs: introduce ->split() to vm_operations_struct" it would be messy to teach vma_mmu_pagesize() about device-dax page mapping sizes in the same (hstate) way that hugetlbfs communicates this attribute. Instead, these patches introduce a new ->pagesize() vm operation. Link: http://lkml.kernel.org/r/151996254734.27922.15813097401404359642.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Reported-by: Jane Chu <jane.chu@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 1 + mm/hugetlb.c | 19 +++++++++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff -puN include/linux/mm.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct include/linux/mm.h --- a/include/linux/mm.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct +++ a/include/linux/mm.h @@ -390,6 +390,7 @@ struct vm_operations_struct { int (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size); void (*map_pages)(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff); + unsigned long (*pagesize)(struct vm_area_struct * area); /* notification that a previously read-only page is about to become * writable, if an error is returned it will cause a SIGBUS */ diff -puN mm/hugetlb.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct mm/hugetlb.c --- a/mm/hugetlb.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct +++ a/mm/hugetlb.c @@ -637,14 +637,9 @@ EXPORT_SYMBOL_GPL(linear_hugepage_index) */ unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) { - struct hstate *hstate; - - if (!is_vm_hugetlb_page(vma)) - return PAGE_SIZE; - - hstate = hstate_vma(vma); - - return 1UL << huge_page_shift(hstate); + if (vma->vm_ops && vma->vm_ops->pagesize) + return vma->vm_ops->pagesize(vma); + return PAGE_SIZE; } EXPORT_SYMBOL_GPL(vma_kernel_pagesize); @@ -3151,6 +3146,13 @@ static int hugetlb_vm_op_split(struct vm return 0; } +static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma) +{ + struct hstate *hstate = hstate_vma(vma); + + return 1UL << huge_page_shift(hstate); +} + /* * We cannot handle pagefaults against hugetlb pages at all. They cause * handle_mm_fault() to try to instantiate regular-sized pages in the @@ -3168,6 +3170,7 @@ const struct vm_operations_struct hugetl .open = hugetlb_vm_op_open, .close = hugetlb_vm_op_close, .split = hugetlb_vm_op_split, + .pagesize = hugetlb_vm_op_pagesize, }; static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
