Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932540AbWEaAJX (ORCPT ); Tue, 30 May 2006 20:09:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932541AbWEaAJX (ORCPT ); Tue, 30 May 2006 20:09:23 -0400 Received: from mail.visionpro.com ([63.91.95.13]:50200 "EHLO chicken.machinevisionproducts.com") by vger.kernel.org with ESMTP id S932540AbWEaAJW convert rfc822-to-8bit (ORCPT ); Tue, 30 May 2006 20:09:22 -0400 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: Sharing memory between kernel and user space X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Date: Tue, 30 May 2006 17:09:21 -0700 Message-ID: <14CFC56C96D8554AA0B8969DB825FEA0012B3321@chicken.machinevisionproducts.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Sharing memory between kernel and user space Thread-Index: AcaEO0EWI7vDXMIcR++YZH69iyZhZwACwXaA From: "Brian D. McGrew" To: "H. Peter Anvin" , Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1692 Lines: 48 As you recommended I do a __get_free_pages in the kernel and then from user space I try and mmap the memory. The mmap is successful but then when I go back and try and read from that location I get a 'can't read of address 0xbf7c8000 (which is the address the kernel gave me back). ??? :b! Brian D. McGrew { brian@visionpro.com || brian@doubledimension.com } -- > This is a test. This is only a test! Had this been an actual emergency, you would have been told to cancel this test and seek professional assistance! -----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of H. Peter Anvin Sent: Tuesday, May 30, 2006 3:46 PM To: linux-kernel@vger.kernel.org Subject: Re: Sharing memory between kernel and user space Followup to: <14CFC56C96D8554AA0B8969DB825FEA0012B331A@chicken.machinevisionproducts. com> By author: "Brian D. McGrew" In newsgroup: linux.dev.kernel > > I have a question about the best way to share memory between user and > kernel space. > In general, allocate the memory in kernel space (via get_free_page et al), and make accessible to userspace via mmap on a device node. -hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/