diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 99 |
1 files changed, 93 insertions, 6 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 64c9d736155c..80217c935608 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -221,7 +221,7 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma, if (vma->vm_flags & VM_DENYWRITE) atomic_inc(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable--; + mapping_unmap_writable(mapping); flush_dcache_mmap_lock(mapping); if (unlikely(vma->vm_flags & VM_NONLINEAR)) @@ -622,7 +622,7 @@ static void __vma_link_file(struct vm_area_struct *vma) if (vma->vm_flags & VM_DENYWRITE) atomic_dec(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) - mapping->i_mmap_writable++; + atomic_inc(&mapping->i_mmap_writable); flush_dcache_mmap_lock(mapping); if (unlikely(vma->vm_flags & VM_NONLINEAR)) @@ -1577,6 +1577,17 @@ munmap_back: if (error) goto free_vma; } + if (vm_flags & VM_SHARED) { + error = mapping_map_writable(file->f_mapping); + if (error) + goto allow_write_and_free_vma; + } + + /* ->mmap() can change vma->vm_file, but must guarantee that + * vma_link() below can deny write-access if VM_DENYWRITE is set + * and map writably if VM_SHARED is set. This usually means the + * new file must not have been exposed to user-space, yet. + */ vma->vm_file = get_file(file); error = file->f_op->mmap(file, vma); if (error) @@ -1616,8 +1627,12 @@ munmap_back: vma_link(mm, vma, prev, rb_link, rb_parent); /* Once vma denies write, undo our temporary denial count */ - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); + if (file) { + if (vm_flags & VM_SHARED) + mapping_unmap_writable(file->f_mapping); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + } file = vma->vm_file; out: perf_event_mmap(vma); @@ -1646,14 +1661,17 @@ out: return addr; unmap_and_free_vma: - if (vm_flags & VM_DENYWRITE) - allow_write_access(file); vma->vm_file = NULL; fput(file); /* Undo any partial mapping done by a device driver. */ unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); charged = 0; + if (vm_flags & VM_SHARED) + mapping_unmap_writable(file->f_mapping); +allow_write_and_free_vma: + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); free_vma: kmem_cache_free(vm_area_cachep, vma); unacct_error: @@ -2586,6 +2604,75 @@ SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) return vm_munmap(addr, len); } + +/* + * Emulation of deprecated remap_file_pages() syscall. + */ +SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, + unsigned long, prot, unsigned long, pgoff, unsigned long, flags) +{ + + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long populate = 0; + unsigned long ret = -EINVAL; + struct file *file; + + pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. " + "See Documentation/vm/remap_file_pages.txt.\n", + current->comm, current->pid); + + if (prot) + return ret; + start = start & PAGE_MASK; + size = size & PAGE_MASK; + + if (start + size <= start) + return ret; + + /* Does pgoff wrap? */ + if (pgoff + (size >> PAGE_SHIFT) < pgoff) + return ret; + + down_write(&mm->mmap_sem); + vma = find_vma(mm, start); + + if (!vma || !(vma->vm_flags & VM_SHARED)) + goto out; + + if (start < vma->vm_start || start + size > vma->vm_end) + goto out; + + if (pgoff == linear_page_index(vma, start)) { + ret = 0; + goto out; + } + + prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; + prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; + prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; + + flags &= MAP_NONBLOCK; + flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; + if (vma->vm_flags & VM_LOCKED) { + flags |= MAP_LOCKED; + /* drop PG_Mlocked flag for over-mapped range */ + munlock_vma_pages_range(vma, start, start + size); + } + + file = get_file(vma->vm_file); + ret = do_mmap_pgoff(vma->vm_file, start, size, + prot, flags, pgoff, &populate); + fput(file); +out: + up_write(&mm->mmap_sem); + if (populate) + mm_populate(ret, populate); + if (!IS_ERR_VALUE(ret)) + ret = 0; + return ret; +} + static inline void verify_mm_writelocked(struct mm_struct *mm) { #ifdef CONFIG_DEBUG_VM |