mirror of https://gitee.com/openkylin/linux.git
1096 lines
27 KiB
C
1096 lines
27 KiB
C
/*
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* blkfront.c
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*
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* XenLinux virtual block device driver.
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*
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
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* Modifications by Mark A. Williamson are (c) Intel Research Cambridge
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* Copyright (c) 2004, Christian Limpach
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* Copyright (c) 2004, Andrew Warfield
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* Copyright (c) 2005, Christopher Clark
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* Copyright (c) 2005, XenSource Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <linux/interrupt.h>
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#include <linux/blkdev.h>
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#include <linux/hdreg.h>
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#include <linux/cdrom.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/scatterlist.h>
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#include <xen/xen.h>
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#include <xen/xenbus.h>
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#include <xen/grant_table.h>
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#include <xen/events.h>
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#include <xen/page.h>
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#include <xen/interface/grant_table.h>
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#include <xen/interface/io/blkif.h>
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#include <xen/interface/io/protocols.h>
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#include <asm/xen/hypervisor.h>
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enum blkif_state {
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BLKIF_STATE_DISCONNECTED,
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BLKIF_STATE_CONNECTED,
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BLKIF_STATE_SUSPENDED,
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};
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struct blk_shadow {
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struct blkif_request req;
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unsigned long request;
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unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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};
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static const struct block_device_operations xlvbd_block_fops;
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#define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
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/*
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* We have one of these per vbd, whether ide, scsi or 'other'. They
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* hang in private_data off the gendisk structure. We may end up
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* putting all kinds of interesting stuff here :-)
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*/
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struct blkfront_info
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{
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struct xenbus_device *xbdev;
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struct gendisk *gd;
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int vdevice;
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blkif_vdev_t handle;
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enum blkif_state connected;
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int ring_ref;
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struct blkif_front_ring ring;
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struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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unsigned int evtchn, irq;
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struct request_queue *rq;
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struct work_struct work;
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struct gnttab_free_callback callback;
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struct blk_shadow shadow[BLK_RING_SIZE];
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unsigned long shadow_free;
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int feature_barrier;
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int is_ready;
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/**
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* The number of people holding this device open. We won't allow a
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* hot-unplug unless this is 0.
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*/
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int users;
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};
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static DEFINE_SPINLOCK(blkif_io_lock);
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#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
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(BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
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#define GRANT_INVALID_REF 0
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#define PARTS_PER_DISK 16
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#define PARTS_PER_EXT_DISK 256
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#define BLKIF_MAJOR(dev) ((dev)>>8)
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#define BLKIF_MINOR(dev) ((dev) & 0xff)
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#define EXT_SHIFT 28
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#define EXTENDED (1<<EXT_SHIFT)
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#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
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#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
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#define DEV_NAME "xvd" /* name in /dev */
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static int get_id_from_freelist(struct blkfront_info *info)
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{
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unsigned long free = info->shadow_free;
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BUG_ON(free >= BLK_RING_SIZE);
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info->shadow_free = info->shadow[free].req.id;
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info->shadow[free].req.id = 0x0fffffee; /* debug */
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return free;
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}
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static void add_id_to_freelist(struct blkfront_info *info,
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unsigned long id)
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{
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info->shadow[id].req.id = info->shadow_free;
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info->shadow[id].request = 0;
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info->shadow_free = id;
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}
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static void blkif_restart_queue_callback(void *arg)
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{
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struct blkfront_info *info = (struct blkfront_info *)arg;
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schedule_work(&info->work);
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}
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static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
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{
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/* We don't have real geometry info, but let's at least return
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values consistent with the size of the device */
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sector_t nsect = get_capacity(bd->bd_disk);
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sector_t cylinders = nsect;
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hg->heads = 0xff;
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hg->sectors = 0x3f;
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sector_div(cylinders, hg->heads * hg->sectors);
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hg->cylinders = cylinders;
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if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
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hg->cylinders = 0xffff;
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return 0;
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}
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static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
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unsigned command, unsigned long argument)
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{
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struct blkfront_info *info = bdev->bd_disk->private_data;
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int i;
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dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
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command, (long)argument);
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switch (command) {
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case CDROMMULTISESSION:
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dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
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for (i = 0; i < sizeof(struct cdrom_multisession); i++)
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if (put_user(0, (char __user *)(argument + i)))
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return -EFAULT;
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return 0;
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case CDROM_GET_CAPABILITY: {
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struct gendisk *gd = info->gd;
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if (gd->flags & GENHD_FL_CD)
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return 0;
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return -EINVAL;
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}
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default:
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/*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
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command);*/
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return -EINVAL; /* same return as native Linux */
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}
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return 0;
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}
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/*
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* blkif_queue_request
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*
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* request block io
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*
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* id: for guest use only.
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* operation: BLKIF_OP_{READ,WRITE,PROBE}
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* buffer: buffer to read/write into. this should be a
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* virtual address in the guest os.
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*/
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static int blkif_queue_request(struct request *req)
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{
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struct blkfront_info *info = req->rq_disk->private_data;
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unsigned long buffer_mfn;
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struct blkif_request *ring_req;
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unsigned long id;
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unsigned int fsect, lsect;
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int i, ref;
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grant_ref_t gref_head;
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struct scatterlist *sg;
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if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
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return 1;
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if (gnttab_alloc_grant_references(
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BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
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gnttab_request_free_callback(
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&info->callback,
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blkif_restart_queue_callback,
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info,
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BLKIF_MAX_SEGMENTS_PER_REQUEST);
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return 1;
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}
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/* Fill out a communications ring structure. */
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ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
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id = get_id_from_freelist(info);
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info->shadow[id].request = (unsigned long)req;
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ring_req->id = id;
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ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req);
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ring_req->handle = info->handle;
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ring_req->operation = rq_data_dir(req) ?
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BLKIF_OP_WRITE : BLKIF_OP_READ;
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if (blk_barrier_rq(req))
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ring_req->operation = BLKIF_OP_WRITE_BARRIER;
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ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
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BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
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for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
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buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
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fsect = sg->offset >> 9;
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lsect = fsect + (sg->length >> 9) - 1;
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/* install a grant reference. */
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ref = gnttab_claim_grant_reference(&gref_head);
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BUG_ON(ref == -ENOSPC);
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gnttab_grant_foreign_access_ref(
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ref,
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info->xbdev->otherend_id,
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buffer_mfn,
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rq_data_dir(req) );
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info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
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ring_req->seg[i] =
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(struct blkif_request_segment) {
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.gref = ref,
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.first_sect = fsect,
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.last_sect = lsect };
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}
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info->ring.req_prod_pvt++;
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/* Keep a private copy so we can reissue requests when recovering. */
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info->shadow[id].req = *ring_req;
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gnttab_free_grant_references(gref_head);
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return 0;
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}
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static inline void flush_requests(struct blkfront_info *info)
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{
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int notify;
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RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
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if (notify)
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notify_remote_via_irq(info->irq);
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}
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/*
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* do_blkif_request
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* read a block; request is in a request queue
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*/
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static void do_blkif_request(struct request_queue *rq)
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{
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struct blkfront_info *info = NULL;
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struct request *req;
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int queued;
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pr_debug("Entered do_blkif_request\n");
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queued = 0;
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while ((req = blk_peek_request(rq)) != NULL) {
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info = req->rq_disk->private_data;
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if (RING_FULL(&info->ring))
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goto wait;
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blk_start_request(req);
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if (!blk_fs_request(req)) {
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__blk_end_request_all(req, -EIO);
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continue;
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}
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pr_debug("do_blk_req %p: cmd %p, sec %lx, "
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"(%u/%u) buffer:%p [%s]\n",
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req, req->cmd, (unsigned long)blk_rq_pos(req),
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blk_rq_cur_sectors(req), blk_rq_sectors(req),
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req->buffer, rq_data_dir(req) ? "write" : "read");
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if (blkif_queue_request(req)) {
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blk_requeue_request(rq, req);
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wait:
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/* Avoid pointless unplugs. */
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blk_stop_queue(rq);
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break;
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}
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queued++;
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}
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if (queued != 0)
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flush_requests(info);
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}
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static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
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{
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struct request_queue *rq;
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rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
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if (rq == NULL)
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return -1;
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queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
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/* Hard sector size and max sectors impersonate the equiv. hardware. */
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blk_queue_logical_block_size(rq, sector_size);
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blk_queue_max_hw_sectors(rq, 512);
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/* Each segment in a request is up to an aligned page in size. */
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blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
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blk_queue_max_segment_size(rq, PAGE_SIZE);
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/* Ensure a merged request will fit in a single I/O ring slot. */
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blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
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/* Make sure buffer addresses are sector-aligned. */
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blk_queue_dma_alignment(rq, 511);
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/* Make sure we don't use bounce buffers. */
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blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
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gd->queue = rq;
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return 0;
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}
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static int xlvbd_barrier(struct blkfront_info *info)
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{
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int err;
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err = blk_queue_ordered(info->rq,
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info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE,
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NULL);
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if (err)
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return err;
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printk(KERN_INFO "blkfront: %s: barriers %s\n",
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info->gd->disk_name,
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info->feature_barrier ? "enabled" : "disabled");
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return 0;
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}
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|
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static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
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struct blkfront_info *info,
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u16 vdisk_info, u16 sector_size)
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{
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struct gendisk *gd;
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int nr_minors = 1;
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int err = -ENODEV;
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unsigned int offset;
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int minor;
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int nr_parts;
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BUG_ON(info->gd != NULL);
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BUG_ON(info->rq != NULL);
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if ((info->vdevice>>EXT_SHIFT) > 1) {
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/* this is above the extended range; something is wrong */
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printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
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return -ENODEV;
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}
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if (!VDEV_IS_EXTENDED(info->vdevice)) {
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minor = BLKIF_MINOR(info->vdevice);
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nr_parts = PARTS_PER_DISK;
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} else {
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minor = BLKIF_MINOR_EXT(info->vdevice);
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nr_parts = PARTS_PER_EXT_DISK;
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}
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if ((minor % nr_parts) == 0)
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nr_minors = nr_parts;
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gd = alloc_disk(nr_minors);
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if (gd == NULL)
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goto out;
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offset = minor / nr_parts;
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|
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if (nr_minors > 1) {
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if (offset < 26)
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sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
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else
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sprintf(gd->disk_name, "%s%c%c", DEV_NAME,
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'a' + ((offset / 26)-1), 'a' + (offset % 26));
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} else {
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if (offset < 26)
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sprintf(gd->disk_name, "%s%c%d", DEV_NAME,
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'a' + offset,
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minor & (nr_parts - 1));
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else
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sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME,
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'a' + ((offset / 26) - 1),
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'a' + (offset % 26),
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minor & (nr_parts - 1));
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}
|
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|
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gd->major = XENVBD_MAJOR;
|
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gd->first_minor = minor;
|
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gd->fops = &xlvbd_block_fops;
|
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gd->private_data = info;
|
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gd->driverfs_dev = &(info->xbdev->dev);
|
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set_capacity(gd, capacity);
|
|
|
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if (xlvbd_init_blk_queue(gd, sector_size)) {
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del_gendisk(gd);
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goto out;
|
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}
|
|
|
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info->rq = gd->queue;
|
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info->gd = gd;
|
|
|
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if (info->feature_barrier)
|
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xlvbd_barrier(info);
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|
|
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if (vdisk_info & VDISK_READONLY)
|
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set_disk_ro(gd, 1);
|
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|
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if (vdisk_info & VDISK_REMOVABLE)
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gd->flags |= GENHD_FL_REMOVABLE;
|
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|
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if (vdisk_info & VDISK_CDROM)
|
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gd->flags |= GENHD_FL_CD;
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|
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return 0;
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|
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out:
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return err;
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}
|
|
|
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static void kick_pending_request_queues(struct blkfront_info *info)
|
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{
|
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if (!RING_FULL(&info->ring)) {
|
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/* Re-enable calldowns. */
|
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blk_start_queue(info->rq);
|
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/* Kick things off immediately. */
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do_blkif_request(info->rq);
|
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}
|
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}
|
|
|
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static void blkif_restart_queue(struct work_struct *work)
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{
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struct blkfront_info *info = container_of(work, struct blkfront_info, work);
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|
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spin_lock_irq(&blkif_io_lock);
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if (info->connected == BLKIF_STATE_CONNECTED)
|
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kick_pending_request_queues(info);
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spin_unlock_irq(&blkif_io_lock);
|
|
}
|
|
|
|
static void blkif_free(struct blkfront_info *info, int suspend)
|
|
{
|
|
/* Prevent new requests being issued until we fix things up. */
|
|
spin_lock_irq(&blkif_io_lock);
|
|
info->connected = suspend ?
|
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BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
|
|
/* No more blkif_request(). */
|
|
if (info->rq)
|
|
blk_stop_queue(info->rq);
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&info->callback);
|
|
spin_unlock_irq(&blkif_io_lock);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_scheduled_work();
|
|
|
|
/* Free resources associated with old device channel. */
|
|
if (info->ring_ref != GRANT_INVALID_REF) {
|
|
gnttab_end_foreign_access(info->ring_ref, 0,
|
|
(unsigned long)info->ring.sring);
|
|
info->ring_ref = GRANT_INVALID_REF;
|
|
info->ring.sring = NULL;
|
|
}
|
|
if (info->irq)
|
|
unbind_from_irqhandler(info->irq, info);
|
|
info->evtchn = info->irq = 0;
|
|
|
|
}
|
|
|
|
static void blkif_completion(struct blk_shadow *s)
|
|
{
|
|
int i;
|
|
for (i = 0; i < s->req.nr_segments; i++)
|
|
gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
|
|
}
|
|
|
|
static irqreturn_t blkif_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct request *req;
|
|
struct blkif_response *bret;
|
|
RING_IDX i, rp;
|
|
unsigned long flags;
|
|
struct blkfront_info *info = (struct blkfront_info *)dev_id;
|
|
int error;
|
|
|
|
spin_lock_irqsave(&blkif_io_lock, flags);
|
|
|
|
if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
|
|
spin_unlock_irqrestore(&blkif_io_lock, flags);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
again:
|
|
rp = info->ring.sring->rsp_prod;
|
|
rmb(); /* Ensure we see queued responses up to 'rp'. */
|
|
|
|
for (i = info->ring.rsp_cons; i != rp; i++) {
|
|
unsigned long id;
|
|
|
|
bret = RING_GET_RESPONSE(&info->ring, i);
|
|
id = bret->id;
|
|
req = (struct request *)info->shadow[id].request;
|
|
|
|
blkif_completion(&info->shadow[id]);
|
|
|
|
add_id_to_freelist(info, id);
|
|
|
|
error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
|
|
switch (bret->operation) {
|
|
case BLKIF_OP_WRITE_BARRIER:
|
|
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
|
|
printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
|
|
info->gd->disk_name);
|
|
error = -EOPNOTSUPP;
|
|
info->feature_barrier = 0;
|
|
xlvbd_barrier(info);
|
|
}
|
|
/* fall through */
|
|
case BLKIF_OP_READ:
|
|
case BLKIF_OP_WRITE:
|
|
if (unlikely(bret->status != BLKIF_RSP_OKAY))
|
|
dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
|
|
"request: %x\n", bret->status);
|
|
|
|
__blk_end_request_all(req, error);
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
info->ring.rsp_cons = i;
|
|
|
|
if (i != info->ring.req_prod_pvt) {
|
|
int more_to_do;
|
|
RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
|
|
if (more_to_do)
|
|
goto again;
|
|
} else
|
|
info->ring.sring->rsp_event = i + 1;
|
|
|
|
kick_pending_request_queues(info);
|
|
|
|
spin_unlock_irqrestore(&blkif_io_lock, flags);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
|
|
static int setup_blkring(struct xenbus_device *dev,
|
|
struct blkfront_info *info)
|
|
{
|
|
struct blkif_sring *sring;
|
|
int err;
|
|
|
|
info->ring_ref = GRANT_INVALID_REF;
|
|
|
|
sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
|
|
if (!sring) {
|
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
|
|
return -ENOMEM;
|
|
}
|
|
SHARED_RING_INIT(sring);
|
|
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
|
|
|
|
sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
|
|
|
|
err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
|
|
if (err < 0) {
|
|
free_page((unsigned long)sring);
|
|
info->ring.sring = NULL;
|
|
goto fail;
|
|
}
|
|
info->ring_ref = err;
|
|
|
|
err = xenbus_alloc_evtchn(dev, &info->evtchn);
|
|
if (err)
|
|
goto fail;
|
|
|
|
err = bind_evtchn_to_irqhandler(info->evtchn,
|
|
blkif_interrupt,
|
|
IRQF_SAMPLE_RANDOM, "blkif", info);
|
|
if (err <= 0) {
|
|
xenbus_dev_fatal(dev, err,
|
|
"bind_evtchn_to_irqhandler failed");
|
|
goto fail;
|
|
}
|
|
info->irq = err;
|
|
|
|
return 0;
|
|
fail:
|
|
blkif_free(info, 0);
|
|
return err;
|
|
}
|
|
|
|
|
|
/* Common code used when first setting up, and when resuming. */
|
|
static int talk_to_backend(struct xenbus_device *dev,
|
|
struct blkfront_info *info)
|
|
{
|
|
const char *message = NULL;
|
|
struct xenbus_transaction xbt;
|
|
int err;
|
|
|
|
/* Create shared ring, alloc event channel. */
|
|
err = setup_blkring(dev, info);
|
|
if (err)
|
|
goto out;
|
|
|
|
again:
|
|
err = xenbus_transaction_start(&xbt);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "starting transaction");
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
err = xenbus_printf(xbt, dev->nodename,
|
|
"ring-ref", "%u", info->ring_ref);
|
|
if (err) {
|
|
message = "writing ring-ref";
|
|
goto abort_transaction;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename,
|
|
"event-channel", "%u", info->evtchn);
|
|
if (err) {
|
|
message = "writing event-channel";
|
|
goto abort_transaction;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
|
|
XEN_IO_PROTO_ABI_NATIVE);
|
|
if (err) {
|
|
message = "writing protocol";
|
|
goto abort_transaction;
|
|
}
|
|
|
|
err = xenbus_transaction_end(xbt, 0);
|
|
if (err) {
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
xenbus_dev_fatal(dev, err, "completing transaction");
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
xenbus_switch_state(dev, XenbusStateInitialised);
|
|
|
|
return 0;
|
|
|
|
abort_transaction:
|
|
xenbus_transaction_end(xbt, 1);
|
|
if (message)
|
|
xenbus_dev_fatal(dev, err, "%s", message);
|
|
destroy_blkring:
|
|
blkif_free(info, 0);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
|
|
/**
|
|
* Entry point to this code when a new device is created. Allocate the basic
|
|
* structures and the ring buffer for communication with the backend, and
|
|
* inform the backend of the appropriate details for those. Switch to
|
|
* Initialised state.
|
|
*/
|
|
static int blkfront_probe(struct xenbus_device *dev,
|
|
const struct xenbus_device_id *id)
|
|
{
|
|
int err, vdevice, i;
|
|
struct blkfront_info *info;
|
|
|
|
/* FIXME: Use dynamic device id if this is not set. */
|
|
err = xenbus_scanf(XBT_NIL, dev->nodename,
|
|
"virtual-device", "%i", &vdevice);
|
|
if (err != 1) {
|
|
/* go looking in the extended area instead */
|
|
err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
|
|
"%i", &vdevice);
|
|
if (err != 1) {
|
|
xenbus_dev_fatal(dev, err, "reading virtual-device");
|
|
return err;
|
|
}
|
|
}
|
|
|
|
info = kzalloc(sizeof(*info), GFP_KERNEL);
|
|
if (!info) {
|
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
info->xbdev = dev;
|
|
info->vdevice = vdevice;
|
|
info->connected = BLKIF_STATE_DISCONNECTED;
|
|
INIT_WORK(&info->work, blkif_restart_queue);
|
|
|
|
for (i = 0; i < BLK_RING_SIZE; i++)
|
|
info->shadow[i].req.id = i+1;
|
|
info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
|
|
|
|
/* Front end dir is a number, which is used as the id. */
|
|
info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
|
|
dev_set_drvdata(&dev->dev, info);
|
|
|
|
err = talk_to_backend(dev, info);
|
|
if (err) {
|
|
kfree(info);
|
|
dev_set_drvdata(&dev->dev, NULL);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int blkif_recover(struct blkfront_info *info)
|
|
{
|
|
int i;
|
|
struct blkif_request *req;
|
|
struct blk_shadow *copy;
|
|
int j;
|
|
|
|
/* Stage 1: Make a safe copy of the shadow state. */
|
|
copy = kmalloc(sizeof(info->shadow),
|
|
GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
|
|
if (!copy)
|
|
return -ENOMEM;
|
|
memcpy(copy, info->shadow, sizeof(info->shadow));
|
|
|
|
/* Stage 2: Set up free list. */
|
|
memset(&info->shadow, 0, sizeof(info->shadow));
|
|
for (i = 0; i < BLK_RING_SIZE; i++)
|
|
info->shadow[i].req.id = i+1;
|
|
info->shadow_free = info->ring.req_prod_pvt;
|
|
info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
|
|
|
|
/* Stage 3: Find pending requests and requeue them. */
|
|
for (i = 0; i < BLK_RING_SIZE; i++) {
|
|
/* Not in use? */
|
|
if (copy[i].request == 0)
|
|
continue;
|
|
|
|
/* Grab a request slot and copy shadow state into it. */
|
|
req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
|
|
*req = copy[i].req;
|
|
|
|
/* We get a new request id, and must reset the shadow state. */
|
|
req->id = get_id_from_freelist(info);
|
|
memcpy(&info->shadow[req->id], ©[i], sizeof(copy[i]));
|
|
|
|
/* Rewrite any grant references invalidated by susp/resume. */
|
|
for (j = 0; j < req->nr_segments; j++)
|
|
gnttab_grant_foreign_access_ref(
|
|
req->seg[j].gref,
|
|
info->xbdev->otherend_id,
|
|
pfn_to_mfn(info->shadow[req->id].frame[j]),
|
|
rq_data_dir(
|
|
(struct request *)
|
|
info->shadow[req->id].request));
|
|
info->shadow[req->id].req = *req;
|
|
|
|
info->ring.req_prod_pvt++;
|
|
}
|
|
|
|
kfree(copy);
|
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
spin_lock_irq(&blkif_io_lock);
|
|
|
|
/* Now safe for us to use the shared ring */
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
|
|
/* Send off requeued requests */
|
|
flush_requests(info);
|
|
|
|
/* Kick any other new requests queued since we resumed */
|
|
kick_pending_request_queues(info);
|
|
|
|
spin_unlock_irq(&blkif_io_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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_get_drvdata(&dev->dev);
|
|
int err;
|
|
|
|
dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
|
|
|
|
blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
|
|
|
|
err = talk_to_backend(dev, info);
|
|
if (info->connected == BLKIF_STATE_SUSPENDED && !err)
|
|
err = blkif_recover(info);
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
/*
|
|
* Invoked when the backend is finally 'ready' (and has told produced
|
|
* the details about the physical device - #sectors, size, etc).
|
|
*/
|
|
static void blkfront_connect(struct blkfront_info *info)
|
|
{
|
|
unsigned long long sectors;
|
|
unsigned long sector_size;
|
|
unsigned int binfo;
|
|
int err;
|
|
|
|
if ((info->connected == BLKIF_STATE_CONNECTED) ||
|
|
(info->connected == BLKIF_STATE_SUSPENDED) )
|
|
return;
|
|
|
|
dev_dbg(&info->xbdev->dev, "%s:%s.\n",
|
|
__func__, info->xbdev->otherend);
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"sectors", "%llu", §ors,
|
|
"info", "%u", &binfo,
|
|
"sector-size", "%lu", §or_size,
|
|
NULL);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err,
|
|
"reading backend fields at %s",
|
|
info->xbdev->otherend);
|
|
return;
|
|
}
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-barrier", "%lu", &info->feature_barrier,
|
|
NULL);
|
|
if (err)
|
|
info->feature_barrier = 0;
|
|
|
|
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
|
|
info->xbdev->otherend);
|
|
return;
|
|
}
|
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
/* Kick pending requests. */
|
|
spin_lock_irq(&blkif_io_lock);
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
kick_pending_request_queues(info);
|
|
spin_unlock_irq(&blkif_io_lock);
|
|
|
|
add_disk(info->gd);
|
|
|
|
info->is_ready = 1;
|
|
}
|
|
|
|
/**
|
|
* Handle the change of state of the backend to Closing. We must delete our
|
|
* device-layer structures now, to ensure that writes are flushed through to
|
|
* the backend. Once is this done, we can switch to Closed in
|
|
* acknowledgement.
|
|
*/
|
|
static void blkfront_closing(struct xenbus_device *dev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
unsigned long flags;
|
|
|
|
dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename);
|
|
|
|
if (info->rq == NULL)
|
|
goto out;
|
|
|
|
spin_lock_irqsave(&blkif_io_lock, flags);
|
|
|
|
/* No more blkif_request(). */
|
|
blk_stop_queue(info->rq);
|
|
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&info->callback);
|
|
spin_unlock_irqrestore(&blkif_io_lock, flags);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_scheduled_work();
|
|
|
|
blk_cleanup_queue(info->rq);
|
|
info->rq = NULL;
|
|
|
|
del_gendisk(info->gd);
|
|
|
|
out:
|
|
xenbus_frontend_closed(dev);
|
|
}
|
|
|
|
/**
|
|
* Callback received when the backend's state changes.
|
|
*/
|
|
static void backend_changed(struct xenbus_device *dev,
|
|
enum xenbus_state backend_state)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
struct block_device *bd;
|
|
|
|
dev_dbg(&dev->dev, "blkfront:backend_changed.\n");
|
|
|
|
switch (backend_state) {
|
|
case XenbusStateInitialising:
|
|
case XenbusStateInitWait:
|
|
case XenbusStateInitialised:
|
|
case XenbusStateUnknown:
|
|
case XenbusStateClosed:
|
|
break;
|
|
|
|
case XenbusStateConnected:
|
|
blkfront_connect(info);
|
|
break;
|
|
|
|
case XenbusStateClosing:
|
|
if (info->gd == NULL) {
|
|
xenbus_frontend_closed(dev);
|
|
break;
|
|
}
|
|
bd = bdget_disk(info->gd, 0);
|
|
if (bd == NULL)
|
|
xenbus_dev_fatal(dev, -ENODEV, "bdget failed");
|
|
|
|
mutex_lock(&bd->bd_mutex);
|
|
if (info->users > 0)
|
|
xenbus_dev_error(dev, -EBUSY,
|
|
"Device in use; refusing to close");
|
|
else
|
|
blkfront_closing(dev);
|
|
mutex_unlock(&bd->bd_mutex);
|
|
bdput(bd);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int blkfront_remove(struct xenbus_device *dev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
dev_dbg(&dev->dev, "blkfront_remove: %s removed\n", dev->nodename);
|
|
|
|
blkif_free(info, 0);
|
|
|
|
kfree(info);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int blkfront_is_ready(struct xenbus_device *dev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
return info->is_ready;
|
|
}
|
|
|
|
static int blkif_open(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
struct blkfront_info *info = bdev->bd_disk->private_data;
|
|
info->users++;
|
|
return 0;
|
|
}
|
|
|
|
static int blkif_release(struct gendisk *disk, fmode_t mode)
|
|
{
|
|
struct blkfront_info *info = disk->private_data;
|
|
info->users--;
|
|
if (info->users == 0) {
|
|
/* Check whether we have been instructed to close. We will
|
|
have ignored this request initially, as the device was
|
|
still mounted. */
|
|
struct xenbus_device *dev = info->xbdev;
|
|
enum xenbus_state state = xenbus_read_driver_state(dev->otherend);
|
|
|
|
if (state == XenbusStateClosing && info->is_ready)
|
|
blkfront_closing(dev);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static const struct block_device_operations xlvbd_block_fops =
|
|
{
|
|
.owner = THIS_MODULE,
|
|
.open = blkif_open,
|
|
.release = blkif_release,
|
|
.getgeo = blkif_getgeo,
|
|
.locked_ioctl = blkif_ioctl,
|
|
};
|
|
|
|
|
|
static const struct xenbus_device_id blkfront_ids[] = {
|
|
{ "vbd" },
|
|
{ "" }
|
|
};
|
|
|
|
static struct xenbus_driver blkfront = {
|
|
.name = "vbd",
|
|
.owner = THIS_MODULE,
|
|
.ids = blkfront_ids,
|
|
.probe = blkfront_probe,
|
|
.remove = blkfront_remove,
|
|
.resume = blkfront_resume,
|
|
.otherend_changed = backend_changed,
|
|
.is_ready = blkfront_is_ready,
|
|
};
|
|
|
|
static int __init xlblk_init(void)
|
|
{
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
|
|
printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
|
|
XENVBD_MAJOR, DEV_NAME);
|
|
return -ENODEV;
|
|
}
|
|
|
|
return xenbus_register_frontend(&blkfront);
|
|
}
|
|
module_init(xlblk_init);
|
|
|
|
|
|
static void __exit xlblk_exit(void)
|
|
{
|
|
return xenbus_unregister_driver(&blkfront);
|
|
}
|
|
module_exit(xlblk_exit);
|
|
|
|
MODULE_DESCRIPTION("Xen virtual block device frontend");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
|
|
MODULE_ALIAS("xen:vbd");
|
|
MODULE_ALIAS("xenblk");
|