diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 86 |
1 files changed, 57 insertions, 29 deletions
diff --git a/mm/memory.c b/mm/memory.c index d67fd9fcf1f2..5c55270729f7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -884,7 +884,7 @@ out_set_pte: return 0; } -int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, +static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, unsigned long addr, unsigned long end) { @@ -2399,7 +2399,10 @@ EXPORT_SYMBOL(unmap_mapping_range); /* * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * + * We return with the mmap_sem locked or unlocked in the same cases + * as does filemap_fault(). */ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, @@ -2688,6 +2691,11 @@ oom: return VM_FAULT_OOM; } +/* + * The mmap_sem must have been held on entry, and may have been + * released depending on flags and vma->vm_ops->fault() return value. + * See filemap_fault() and __lock_page_retry(). + */ static int __do_fault(struct vm_area_struct *vma, unsigned long address, pgoff_t pgoff, unsigned int flags, struct page **page) { @@ -2744,7 +2752,7 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address, if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); else if (pte_file(*pte) && pte_file_soft_dirty(*pte)) - pte_mksoft_dirty(entry); + entry = pte_mksoft_dirty(entry); if (anon) { inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); page_add_new_anon_rmap(page, vma, address); @@ -2758,22 +2766,8 @@ void do_set_pte(struct vm_area_struct *vma, unsigned long address, update_mmu_cache(vma, address, pte); } -static unsigned long fault_around_bytes = 65536; - -/* - * fault_around_pages() and fault_around_mask() round down fault_around_bytes - * to nearest page order. It's what do_fault_around() expects to see. - */ -static inline unsigned long fault_around_pages(void) -{ - return rounddown_pow_of_two(fault_around_bytes) / PAGE_SIZE; -} - -static inline unsigned long fault_around_mask(void) -{ - return ~(rounddown_pow_of_two(fault_around_bytes) - 1) & PAGE_MASK; -} - +static unsigned long fault_around_bytes __read_mostly = + rounddown_pow_of_two(65536); #ifdef CONFIG_DEBUG_FS static int fault_around_bytes_get(void *data, u64 *val) @@ -2782,11 +2776,19 @@ static int fault_around_bytes_get(void *data, u64 *val) return 0; } +/* + * fault_around_pages() and fault_around_mask() expects fault_around_bytes + * rounded down to nearest page order. It's what do_fault_around() expects to + * see. + */ static int fault_around_bytes_set(void *data, u64 val) { if (val / PAGE_SIZE > PTRS_PER_PTE) return -EINVAL; - fault_around_bytes = val; + if (val > PAGE_SIZE) + fault_around_bytes = rounddown_pow_of_two(val); + else + fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ return 0; } DEFINE_SIMPLE_ATTRIBUTE(fault_around_bytes_fops, @@ -2831,12 +2833,15 @@ late_initcall(fault_around_debugfs); static void do_fault_around(struct vm_area_struct *vma, unsigned long address, pte_t *pte, pgoff_t pgoff, unsigned int flags) { - unsigned long start_addr; + unsigned long start_addr, nr_pages, mask; pgoff_t max_pgoff; struct vm_fault vmf; int off; - start_addr = max(address & fault_around_mask(), vma->vm_start); + nr_pages = ACCESS_ONCE(fault_around_bytes) >> PAGE_SHIFT; + mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; + + start_addr = max(address & mask, vma->vm_start); off = ((address - start_addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); pte -= off; pgoff -= off; @@ -2848,7 +2853,7 @@ static void do_fault_around(struct vm_area_struct *vma, unsigned long address, max_pgoff = pgoff - ((start_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + PTRS_PER_PTE - 1; max_pgoff = min3(max_pgoff, vma_pages(vma) + vma->vm_pgoff - 1, - pgoff + fault_around_pages() - 1); + pgoff + nr_pages - 1); /* Check if it makes any sense to call ->map_pages */ while (!pte_none(*pte)) { @@ -2882,7 +2887,8 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, * if page by the offset is not ready to be mapped (cold cache or * something). */ - if (vma->vm_ops->map_pages && fault_around_pages() > 1) { + if (vma->vm_ops->map_pages && !(flags & FAULT_FLAG_NONLINEAR) && + fault_around_bytes >> PAGE_SHIFT > 1) { pte = pte_offset_map_lock(mm, pmd, address, &ptl); do_fault_around(vma, address, pte, pgoff, flags); if (!pte_same(*pte, orig_pte)) @@ -3012,6 +3018,12 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, return ret; } +/* + * We enter with non-exclusive mmap_sem (to exclude vma changes, + * but allow concurrent faults). + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). + */ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, unsigned int flags, pte_t orig_pte) @@ -3036,7 +3048,9 @@ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, * * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *page_table, pmd_t *pmd, @@ -3168,7 +3182,10 @@ out: * * We enter with non-exclusive mmap_sem (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. - * We return with mmap_sem still held, but pte unmapped and unlocked. + * We return with pte unmapped and unlocked. + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int handle_pte_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, @@ -3177,7 +3194,7 @@ static int handle_pte_fault(struct mm_struct *mm, pte_t entry; spinlock_t *ptl; - entry = *pte; + entry = ACCESS_ONCE(*pte); if (!pte_present(entry)) { if (pte_none(entry)) { if (vma->vm_ops) { @@ -3228,6 +3245,9 @@ unlock: /* * By the time we get here, we already hold the mm semaphore + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). */ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, unsigned int flags) @@ -3309,6 +3329,12 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, return handle_pte_fault(mm, vma, address, pte, pmd, flags); } +/* + * By the time we get here, we already hold the mm semaphore + * + * The mmap_sem may have been released depending on flags and our + * return value. See filemap_fault() and __lock_page_or_retry(). + */ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, unsigned int flags) { @@ -3587,11 +3613,13 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, ret = get_user_pages(tsk, mm, addr, 1, write, 1, &page, &vma); if (ret <= 0) { +#ifndef CONFIG_HAVE_IOREMAP_PROT + break; +#else /* * Check if this is a VM_IO | VM_PFNMAP VMA, which * we can access using slightly different code. */ -#ifdef CONFIG_HAVE_IOREMAP_PROT vma = find_vma(mm, addr); if (!vma || vma->vm_start > addr) break; @@ -3599,9 +3627,9 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, ret = vma->vm_ops->access(vma, addr, buf, len, write); if (ret <= 0) -#endif break; bytes = ret; +#endif } else { bytes = len; offset = addr & (PAGE_SIZE-1); |