From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 14 Jan 2003 17:26:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 14 Jan 2003 17:26:55 -0500 Received: from ns.temetra.com ([64.239.6.61]:56812 "EHLO temetra.com") by vger.kernel.org with ESMTP id ; Tue, 14 Jan 2003 17:26:54 -0500 Date: Tue, 14 Jan 2003 17:35:45 -0500 Message-Id: <200301142235.RAA23806@temetra.com> From: Brian Kelly To: linux-kernel@vger.kernel.org Subject: How to setup a buffer_head in a driver Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm writing a device driver that among other things needs to write data, manufactured by the driver itself, to a block device. I have this data in block sized kmalloc()'d chunks. So what I'm doing is allocating a struct buffer_head, initialising it, fill out it's various fields and send it to generic_make_request(). Something like the following [inspired by looking at various drivers like loop and ram]: do { if((bh = kmem_cache_alloc(bh_cachep, SLAB_NOIO)) != NULL){ break; } run_task_queue(&tq_disk); schedule_timeout(HZ); } while (1); memset(bh, 0, sizeof(*bh)); bh->b_size = size; bh->b_dev = dev; bh->b_rdev = dev; bh->b_data = data; init_waitqueue_head(&bh->b_wait); bh->b_rsector = sect; bh->b_end_io = write_done; bh->b_private = NULL; generic_make_request(WRITE, bh); Now this causes a panic in ll_rw_blk.c because the b_state isn't set correctly. I experimented with this a little but decided I needed some proper direction on this whole endeavour. Soooo, what do I really need to do? What's the correct way to do what I want to do or could someone point me at an existing driver that does this sort of thing. Thanks, Brian -- bkelly@sulaco.com