diff options
Diffstat (limited to 'mm/fremap.c')
-rw-r--r-- | mm/fremap.c | 103 |
1 files changed, 72 insertions, 31 deletions
diff --git a/mm/fremap.c b/mm/fremap.c index 4e3f53dd5fd..01e51f01b84 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -126,6 +126,25 @@ out: return err; } +static int populate_range(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, unsigned long size, pgoff_t pgoff) +{ + int err; + + do { + err = install_file_pte(mm, vma, addr, pgoff, vma->vm_page_prot); + if (err) + return err; + + size -= PAGE_SIZE; + addr += PAGE_SIZE; + pgoff++; + } while (size); + + return 0; + +} + /*** * sys_remap_file_pages - remap arbitrary pages of a shared backing store * file within an existing vma. @@ -183,41 +202,63 @@ asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, * the single existing vma. vm_private_data is used as a * swapout cursor in a VM_NONLINEAR vma. */ - if (vma && (vma->vm_flags & VM_SHARED) && - (!vma->vm_private_data || (vma->vm_flags & VM_NONLINEAR)) && - vma->vm_ops && vma->vm_ops->populate && - end > start && start >= vma->vm_start && - end <= vma->vm_end) { - - /* Must set VM_NONLINEAR before any pages are populated. */ - if (pgoff != linear_page_index(vma, start) && - !(vma->vm_flags & VM_NONLINEAR)) { - if (!has_write_lock) { - up_read(&mm->mmap_sem); - down_write(&mm->mmap_sem); - has_write_lock = 1; - goto retry; + if (!vma || !(vma->vm_flags & VM_SHARED)) + goto out; + + if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR)) + goto out; + + if ((!vma->vm_ops || !vma->vm_ops->populate) && + !(vma->vm_flags & VM_CAN_NONLINEAR)) + goto out; + + if (end <= start || start < vma->vm_start || end > vma->vm_end) + goto out; + + /* Must set VM_NONLINEAR before any pages are populated. */ + if (!(vma->vm_flags & VM_NONLINEAR)) { + /* Don't need a nonlinear mapping, exit success */ + if (pgoff == linear_page_index(vma, start)) { + err = 0; + goto out; + } + + if (!has_write_lock) { + up_read(&mm->mmap_sem); + down_write(&mm->mmap_sem); + has_write_lock = 1; + goto retry; + } + mapping = vma->vm_file->f_mapping; + spin_lock(&mapping->i_mmap_lock); + flush_dcache_mmap_lock(mapping); + vma->vm_flags |= VM_NONLINEAR; + vma_prio_tree_remove(vma, &mapping->i_mmap); + vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); + flush_dcache_mmap_unlock(mapping); + spin_unlock(&mapping->i_mmap_lock); + } + + if (vma->vm_flags & VM_CAN_NONLINEAR) { + err = populate_range(mm, vma, start, size, pgoff); + if (!err && !(flags & MAP_NONBLOCK)) { + if (unlikely(has_write_lock)) { + downgrade_write(&mm->mmap_sem); + has_write_lock = 0; } - mapping = vma->vm_file->f_mapping; - spin_lock(&mapping->i_mmap_lock); - flush_dcache_mmap_lock(mapping); - vma->vm_flags |= VM_NONLINEAR; - vma_prio_tree_remove(vma, &mapping->i_mmap); - vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); - flush_dcache_mmap_unlock(mapping); - spin_unlock(&mapping->i_mmap_lock); + make_pages_present(start, start+size); } + } else + err = vma->vm_ops->populate(vma, start, size, vma->vm_page_prot, + pgoff, flags & MAP_NONBLOCK); - err = vma->vm_ops->populate(vma, start, size, - vma->vm_page_prot, - pgoff, flags & MAP_NONBLOCK); + /* + * We can't clear VM_NONLINEAR because we'd have to do + * it after ->populate completes, and that would prevent + * downgrading the lock. (Locks can't be upgraded). + */ - /* - * We can't clear VM_NONLINEAR because we'd have to do - * it after ->populate completes, and that would prevent - * downgrading the lock. (Locks can't be upgraded). - */ - } +out: if (likely(!has_write_lock)) up_read(&mm->mmap_sem); else |