- /* We must do this while still holding mmap_sem for write, as we
- * need to be protected against userspace attempting to mremap()
- * or munmap() the ring buffer.
- */
- ctx->nr_pages = get_user_pages(current, mm, ctx->mmap_base, nr_pages,
- 1, 0, ctx->ring_pages, NULL);
-
- /* Dropping the reference here is safe as the page cache will hold
- * onto the pages for us. It is also required so that page migration
- * can unmap the pages and get the right reference count.
- */
- for (i = 0; i < ctx->nr_pages; i++)
- put_page(ctx->ring_pages[i]);
-
- up_write(&mm->mmap_sem);
-
- if (unlikely(ctx->nr_pages != nr_pages)) {
- aio_free_ring(ctx);
- return -EAGAIN;
- }
-