From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267829AbUHWUqy (ORCPT ); Mon, 23 Aug 2004 16:46:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267765AbUHWUpr (ORCPT ); Mon, 23 Aug 2004 16:45:47 -0400 Received: from zcars04e.nortelnetworks.com ([47.129.242.56]:64462 "EHLO zcars04e.nortelnetworks.com") by vger.kernel.org with ESMTP id S267792AbUHWUpX (ORCPT ); Mon, 23 Aug 2004 16:45:23 -0400 Message-ID: <412A5759.7060401@nortelnetworks.com> Date: Mon, 23 Aug 2004 16:45:13 -0400 X-Sybari-Space: 00000000 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Linux kernel Subject: question on char driver mmap Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I have a need for a device driver to map a page of memory between interrupt handlers and userspace. It's been suggested that I use something like the following code (simplified): unsigned long mypage; int my_mmap(struct file *filp, struct vm_area_struct *vma) { unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; if (offset & ~PAGE_MASK) return -ENXIO; mypage = __get_free_page(GFP_KERNEL); SetPageReserved(virt_to_page(mypage)); remap_page_range(vma->vm_start, virt_to_phys((void *) mypage), PAGE_SIZE, vma->vm_page_prot); return 0; } This seems to work. If I do this, however, do I need to hook into the munmap() file operations to handle unmapping, clearing the reserved bit, and freeing the page, or will the memory subsystem do it for me? Thanks, Chris