diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/mm/memory.c b/mm/memory.c index bc929dbad21..5d2ef1217d0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1462,10 +1462,11 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, EXPORT_SYMBOL_GPL(zap_vma_ptes); /** - * follow_page - look up a page descriptor from a user-virtual address + * follow_page_mask - look up a page descriptor from a user-virtual address * @vma: vm_area_struct mapping @address * @address: virtual address to look up * @flags: flags modifying lookup behaviour + * @page_mask: on output, *page_mask is set according to the size of the page * * @flags can have FOLL_ flags set, defined in <linux/mm.h> * @@ -1473,8 +1474,9 @@ EXPORT_SYMBOL_GPL(zap_vma_ptes); * an error pointer if there is a mapping to something not represented * by a page descriptor (see also vm_normal_page()). */ -struct page *follow_page(struct vm_area_struct *vma, unsigned long address, - unsigned int flags) +struct page *follow_page_mask(struct vm_area_struct *vma, + unsigned long address, unsigned int flags, + unsigned int *page_mask) { pgd_t *pgd; pud_t *pud; @@ -1484,6 +1486,8 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, struct page *page; struct mm_struct *mm = vma->vm_mm; + *page_mask = 0; + page = follow_huge_addr(mm, address, flags & FOLL_WRITE); if (!IS_ERR(page)) { BUG_ON(flags & FOLL_GET); @@ -1530,6 +1534,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, page = follow_trans_huge_pmd(vma, address, pmd, flags); spin_unlock(&mm->page_table_lock); + *page_mask = HPAGE_PMD_NR - 1; goto out; } } else @@ -1684,6 +1689,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, { long i; unsigned long vm_flags; + unsigned int page_mask; if (!nr_pages) return 0; @@ -1761,6 +1767,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, get_page(page); } pte_unmap(pte); + page_mask = 0; goto next_page; } @@ -1778,6 +1785,7 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, do { struct page *page; unsigned int foll_flags = gup_flags; + unsigned int page_increm; /* * If we have a pending SIGKILL, don't keep faulting @@ -1787,7 +1795,8 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, return i ? i : -ERESTARTSYS; cond_resched(); - while (!(page = follow_page(vma, start, foll_flags))) { + while (!(page = follow_page_mask(vma, start, + foll_flags, &page_mask))) { int ret; unsigned int fault_flags = 0; @@ -1861,13 +1870,19 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, flush_anon_page(vma, page, start); flush_dcache_page(page); + page_mask = 0; } next_page: - if (vmas) + if (vmas) { vmas[i] = vma; - i++; - start += PAGE_SIZE; - nr_pages--; + page_mask = 0; + } + page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask); + if (page_increm > nr_pages) + page_increm = nr_pages; + i += page_increm; + start += page_increm * PAGE_SIZE; + nr_pages -= page_increm; } while (nr_pages && start < vma->vm_end); } while (nr_pages); return i; |