From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932105AbWGRNPN (ORCPT ); Tue, 18 Jul 2006 09:15:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932191AbWGRNPM (ORCPT ); Tue, 18 Jul 2006 09:15:12 -0400 Received: from mail.cs.umn.edu ([128.101.34.202]:34198 "EHLO mail.cs.umn.edu") by vger.kernel.org with ESMTP id S932105AbWGRNPK (ORCPT ); Tue, 18 Jul 2006 09:15:10 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17596.56260.541661.919437@hound.rchland.ibm.com> Date: Tue, 18 Jul 2006 08:01:56 -0500 To: Chris Wright Cc: linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Jeremy Fitzhardinge , Andi Kleen , Andrew Morton , Rusty Russell , Zachary Amsden , Ian Pratt , Christian Limpach Subject: [RFC PATCH 33/33] Add Xen virtual block device driver. In-Reply-To: <20060718091958.657332000@sous-sol.org> References: <20060718091807.467468000@sous-sol.org> <20060718091958.657332000@sous-sol.org> X-Mailer: VM 7.19 under Emacs 21.4.1 From: boutcher@cs.umn.edu (Dave Boutcher) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 Jul 2006 00:00:33 -0700, Chris Wright said: > > The block device frontend driver allows the kernel to access block > devices exported exported by a virtual machine containing a physical > block device driver. First, I think this belongs in drivers/block (and the network driver belongs in drivers/net). If we're going to bring xen to the party, lets not leave it hiding out in a corner. > +static void connect(struct blkfront_info *); > +static void blkfront_closing(struct xenbus_device *); > +static int blkfront_remove(struct xenbus_device *); > +static int talk_to_backend(struct xenbus_device *, struct blkfront_info *); > +static int setup_blkring(struct xenbus_device *, struct blkfront_info *); > + > +static void kick_pending_request_queues(struct blkfront_info *); > + > +static irqreturn_t blkif_int(int irq, void *dev_id, struct pt_regs *ptregs); > +static void blkif_restart_queue(void *arg); > +static void blkif_recover(struct blkfront_info *); > +static void blkif_completion(struct blk_shadow *); > +static void blkif_free(struct blkfront_info *, int); I'm pretty sure you can rearrange the code to get rid of the forward references. > +/** > + * We are reconnecting to the backend, due to a suspend/resume, or a backend > + * driver restart. We tear down our blkif structure and recreate it, but > + * leave the device-layer structures intact so that this is transparent to the > + * rest of the kernel. > + */ > +static int blkfront_resume(struct xenbus_device *dev) > +{ > + struct blkfront_info *info = dev->dev.driver_data; > + int err; > + > + DPRINTK("blkfront_resume: %s\n", dev->nodename); > + > + blkif_free(info, 1); > + > + err = talk_to_backend(dev, info); > + if (!err) > + blkif_recover(info); > + > + return err; > +} Should blkfront_resume grab blkif_io_lock? > + switch (backend_state) { > + case XenbusStateUnknown: > + case XenbusStateInitialising: > + case XenbusStateInitWait: > + case XenbusStateInitialised: > + case XenbusStateClosed: This actually should get fixed elsewhere, but SillyCaps??? > +static inline int GET_ID_FROM_FREELIST( > + struct blkfront_info *info) > +{ > + unsigned long free = info->shadow_free; > + BUG_ON(free > BLK_RING_SIZE); > + info->shadow_free = info->shadow[free].req.id; > + info->shadow[free].req.id = 0x0fffffee; /* debug */ > + return free; > +} > + > +static inline void ADD_ID_TO_FREELIST( > + struct blkfront_info *info, unsigned long id) > +{ > + info->shadow[id].req.id = info->shadow_free; > + info->shadow[id].request = 0; > + info->shadow_free = id; > +} A real nit..but why are these routines SHOUTING? > +int blkif_release(struct inode *inode, struct file *filep) > +{ > + struct blkfront_info *info = inode->i_bdev->bd_disk->private_data; > + info->users--; > + if (info->users == 0) { Hrm...this strikes me as racey. Don't you need at least a memory barrier here to handle SMP? > +static struct xlbd_major_info xvd_major_info = { > + .major = 201, > + .type = &xvd_type_info > +}; I've forgotten what the current policy is around new major numbers. Dave B