diff options
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 128 |
1 files changed, 86 insertions, 42 deletions
@@ -234,6 +234,16 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, return page; return no_page_table(vma, flags); } +retry: + if (!pmd_present(*pmd)) { + if (likely(!(flags & FOLL_MIGRATION))) + return no_page_table(vma, flags); + VM_BUG_ON(thp_migration_supported() && + !is_pmd_migration_entry(*pmd)); + if (is_pmd_migration_entry(*pmd)) + pmd_migration_entry_wait(mm, pmd); + goto retry; + } if (pmd_devmap(*pmd)) { ptl = pmd_lock(mm, pmd); page = follow_devmap_pmd(vma, address, pmd, flags); @@ -247,7 +257,15 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, if ((flags & FOLL_NUMA) && pmd_protnone(*pmd)) return no_page_table(vma, flags); +retry_locked: ptl = pmd_lock(mm, pmd); + if (unlikely(!pmd_present(*pmd))) { + spin_unlock(ptl); + if (likely(!(flags & FOLL_MIGRATION))) + return no_page_table(vma, flags); + pmd_migration_entry_wait(mm, pmd); + goto retry_locked; + } if (unlikely(!pmd_trans_huge(*pmd))) { spin_unlock(ptl); return follow_page_pte(vma, address, pmd, flags); @@ -424,7 +442,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, pud = pud_offset(p4d, address); BUG_ON(pud_none(*pud)); pmd = pmd_offset(pud, address); - if (pmd_none(*pmd)) + if (!pmd_present(*pmd)) return -EFAULT; VM_BUG_ON(pmd_trans_huge(*pmd)); pte = pte_offset_map(pmd, address); @@ -438,6 +456,13 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte))) goto unmap; *page = pte_page(*pte); + + /* + * This should never happen (a device public page in the gate + * area). + */ + if (is_device_public_page(*page)) + goto unmap; } get_page(*page); out: @@ -1352,7 +1377,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, } #endif /* __HAVE_ARCH_PTE_SPECIAL */ -#ifdef __HAVE_ARCH_PTE_DEVMAP +#if defined(__HAVE_ARCH_PTE_DEVMAP) && defined(CONFIG_TRANSPARENT_HUGEPAGE) static int __gup_device_huge(unsigned long pfn, unsigned long addr, unsigned long end, struct page **pages, int *nr) { @@ -1534,7 +1559,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, pmd_t pmd = READ_ONCE(*pmdp); next = pmd_addr_end(addr, end); - if (pmd_none(pmd)) + if (!pmd_present(pmd)) return 0; if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd))) { @@ -1618,6 +1643,47 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, return 1; } +static void gup_pgd_range(unsigned long addr, unsigned long end, + int write, struct page **pages, int *nr) +{ + unsigned long next; + pgd_t *pgdp; + + pgdp = pgd_offset(current->mm, addr); + do { + pgd_t pgd = READ_ONCE(*pgdp); + + next = pgd_addr_end(addr, end); + if (pgd_none(pgd)) + return; + if (unlikely(pgd_huge(pgd))) { + if (!gup_huge_pgd(pgd, pgdp, addr, next, write, + pages, nr)) + return; + } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { + if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, + PGDIR_SHIFT, next, write, pages, nr)) + return; + } else if (!gup_p4d_range(pgd, addr, next, write, pages, nr)) + return; + } while (pgdp++, addr = next, addr != end); +} + +#ifndef gup_fast_permitted +/* + * Check if it's allowed to use __get_user_pages_fast() for the range, or + * we need to fall back to the slow version: + */ +bool gup_fast_permitted(unsigned long start, int nr_pages, int write) +{ + unsigned long len, end; + + len = (unsigned long) nr_pages << PAGE_SHIFT; + end = start + len; + return end >= start; +} +#endif + /* * Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to * the regular GUP. It will only return non-negative values. @@ -1625,10 +1691,8 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, int __get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { - struct mm_struct *mm = current->mm; unsigned long addr, len, end; - unsigned long next, flags; - pgd_t *pgdp; + unsigned long flags; int nr = 0; start &= PAGE_MASK; @@ -1652,45 +1716,15 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, * block IPIs that come from THPs splitting. */ - local_irq_save(flags); - pgdp = pgd_offset(mm, addr); - do { - pgd_t pgd = READ_ONCE(*pgdp); - - next = pgd_addr_end(addr, end); - if (pgd_none(pgd)) - break; - if (unlikely(pgd_huge(pgd))) { - if (!gup_huge_pgd(pgd, pgdp, addr, next, write, - pages, &nr)) - break; - } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { - if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, - PGDIR_SHIFT, next, write, pages, &nr)) - break; - } else if (!gup_p4d_range(pgd, addr, next, write, pages, &nr)) - break; - } while (pgdp++, addr = next, addr != end); - local_irq_restore(flags); + if (gup_fast_permitted(start, nr_pages, write)) { + local_irq_save(flags); + gup_pgd_range(addr, end, write, pages, &nr); + local_irq_restore(flags); + } return nr; } -#ifndef gup_fast_permitted -/* - * Check if it's allowed to use __get_user_pages_fast() for the range, or - * we need to fall back to the slow version: - */ -bool gup_fast_permitted(unsigned long start, int nr_pages, int write) -{ - unsigned long len, end; - - len = (unsigned long) nr_pages << PAGE_SHIFT; - end = start + len; - return end >= start; -} -#endif - /** * get_user_pages_fast() - pin user pages in memory * @start: starting user address @@ -1710,12 +1744,22 @@ bool gup_fast_permitted(unsigned long start, int nr_pages, int write) int get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { + unsigned long addr, len, end; int nr = 0, ret = 0; start &= PAGE_MASK; + addr = start; + len = (unsigned long) nr_pages << PAGE_SHIFT; + end = start + len; + + if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ, + (void __user *)start, len))) + return 0; if (gup_fast_permitted(start, nr_pages, write)) { - nr = __get_user_pages_fast(start, nr_pages, write, pages); + local_irq_disable(); + gup_pgd_range(addr, end, write, pages, &nr); + local_irq_enable(); ret = nr; } |