Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262776AbTKCStX (ORCPT ); Mon, 3 Nov 2003 13:49:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262796AbTKCStX (ORCPT ); Mon, 3 Nov 2003 13:49:23 -0500 Received: from nat9.steeleye.com ([65.114.3.137]:38406 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S262776AbTKCStO (ORCPT ); Mon, 3 Nov 2003 13:49:14 -0500 Subject: Re: virt_to_page/pci_map_page vs. pci_map_single From: James Bottomley To: Jes Sorensen Cc: Jamie Wellnitz , Linux Kernel Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-9) Date: 03 Nov 2003 12:48:42 -0600 Message-Id: <1067885332.2076.13.camel@mulgrave> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1076 Lines: 29 Jamie> The Document/DMA-mapping.txt in 2.6.0-test9 says "To map a Jamie> single region, you do:" and then shows pci_map_single. Is Jamie> DMA-mapping.txt in need of patching? Sounds like it needs an update. Erm, I don't think so. pci_map_single() covers a different use case from pci_map_page(). The thing pci_map_single() can do that pci_map_page() can't is cope with contiguous regions greater than PAGE_SIZE in length (which you get either from kmalloc() or __get_free_pages()). This feature is used in the SCSI layer for instance. There has been talk of deprecating dma_map_single() in favour of dma_map_sg() (i.e. make all transfers use scatter/gather and eliminate dma_map_single() in favour of a single sg entry table) but nothing has been done about it (at least as far as I know). James - 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/