mirror of https://gitee.com/openkylin/linux.git
422 lines
9.7 KiB
C
422 lines
9.7 KiB
C
/*
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* The Guest 9p transport driver
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*
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* This is a block based transport driver based on the lguest block driver
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* code.
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*
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*/
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/*
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* Copyright (C) 2007 Eric Van Hensbergen, IBM Corporation
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*
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* Based on virtio console driver
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* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include <linux/in.h>
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/ipv6.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/un.h>
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#include <linux/uaccess.h>
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#include <linux/inet.h>
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#include <linux/idr.h>
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#include <linux/file.h>
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#include <net/9p/9p.h>
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#include <linux/parser.h>
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#include <net/9p/transport.h>
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#include <linux/scatterlist.h>
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#include <linux/virtio.h>
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#include <linux/virtio_9p.h>
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#define VIRTQUEUE_NUM 128
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/* a single mutex to manage channel initialization and attachment */
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static DECLARE_MUTEX(virtio_9p_lock);
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/* global which tracks highest initialized channel */
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static int chan_index;
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#define P9_INIT_MAXTAG 16
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#define REQ_STATUS_IDLE 0
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#define REQ_STATUS_SENT 1
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#define REQ_STATUS_RCVD 2
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#define REQ_STATUS_FLSH 3
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struct p9_req_t {
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int status;
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wait_queue_head_t *wq;
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};
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/* We keep all per-channel information in a structure.
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* This structure is allocated within the devices dev->mem space.
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* A pointer to the structure will get put in the transport private.
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*/
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static struct virtio_chan {
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bool initialized; /* channel is initialized */
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bool inuse; /* channel is in use */
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spinlock_t lock;
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struct virtio_device *vdev;
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struct virtqueue *vq;
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struct p9_idpool *tagpool;
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struct p9_req_t *reqs;
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int max_tag;
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/* Scatterlist: can be too big for stack. */
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struct scatterlist sg[VIRTQUEUE_NUM];
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} channels[MAX_9P_CHAN];
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/* Lookup requests by tag */
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static struct p9_req_t *p9_lookup_tag(struct virtio_chan *c, u16 tag)
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{
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/* This looks up the original request by tag so we know which
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* buffer to read the data into */
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tag++;
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while (tag >= c->max_tag) {
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int old_max = c->max_tag;
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int count;
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if (c->max_tag)
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c->max_tag *= 2;
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else
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c->max_tag = P9_INIT_MAXTAG;
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c->reqs = krealloc(c->reqs, sizeof(struct p9_req_t)*c->max_tag,
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GFP_ATOMIC);
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if (!c->reqs) {
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printk(KERN_ERR "Couldn't grow tag array\n");
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BUG();
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}
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for (count = old_max; count < c->max_tag; count++) {
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c->reqs[count].status = REQ_STATUS_IDLE;
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c->reqs[count].wq = kmalloc(sizeof(wait_queue_head_t),
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GFP_ATOMIC);
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if (!c->reqs[count].wq) {
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printk(KERN_ERR "Couldn't grow tag array\n");
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BUG();
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}
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init_waitqueue_head(c->reqs[count].wq);
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}
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}
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return &c->reqs[tag];
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}
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/* How many bytes left in this page. */
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static unsigned int rest_of_page(void *data)
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{
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return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
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}
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static void p9_virtio_close(struct p9_trans *trans)
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{
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struct virtio_chan *chan = trans->priv;
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int count;
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unsigned int flags;
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spin_lock_irqsave(&chan->lock, flags);
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p9_idpool_destroy(chan->tagpool);
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for (count = 0; count < chan->max_tag; count++)
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kfree(chan->reqs[count].wq);
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kfree(chan->reqs);
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chan->max_tag = 0;
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spin_unlock_irqrestore(&chan->lock, flags);
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down(&virtio_9p_lock);
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chan->inuse = false;
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up(&virtio_9p_lock);
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kfree(trans);
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}
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static void req_done(struct virtqueue *vq)
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{
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struct virtio_chan *chan = vq->vdev->priv;
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struct p9_fcall *rc;
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unsigned int len;
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unsigned long flags;
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struct p9_req_t *req;
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spin_lock_irqsave(&chan->lock, flags);
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while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) {
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req = p9_lookup_tag(chan, rc->tag);
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req->status = REQ_STATUS_RCVD;
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wake_up(req->wq);
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}
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/* In case queue is stopped waiting for more buffers. */
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spin_unlock_irqrestore(&chan->lock, flags);
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}
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static int
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pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
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int count)
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{
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int s;
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int index = start;
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while (count) {
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s = rest_of_page(data);
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if (s > count)
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s = count;
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sg_set_buf(&sg[index++], data, s);
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count -= s;
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data += s;
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BUG_ON(index > limit);
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}
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return index-start;
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}
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static int
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p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
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{
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int in, out;
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int n, err, size;
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struct virtio_chan *chan = t->priv;
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char *rdata;
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struct p9_req_t *req;
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unsigned long flags;
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if (*rc == NULL) {
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*rc = kmalloc(sizeof(struct p9_fcall) + t->msize, GFP_KERNEL);
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if (!*rc)
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return -ENOMEM;
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}
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rdata = (char *)*rc+sizeof(struct p9_fcall);
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n = P9_NOTAG;
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if (tc->id != P9_TVERSION) {
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n = p9_idpool_get(chan->tagpool);
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if (n < 0)
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return -ENOMEM;
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}
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spin_lock_irqsave(&chan->lock, flags);
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req = p9_lookup_tag(chan, n);
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spin_unlock_irqrestore(&chan->lock, flags);
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p9_set_tag(tc, n);
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P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio rpc tag %d\n", n);
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out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, tc->sdata, tc->size);
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in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, t->msize);
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req->status = REQ_STATUS_SENT;
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if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, tc)) {
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P9_DPRINTK(P9_DEBUG_TRANS,
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"9p debug: virtio rpc add_buf returned failure");
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return -EIO;
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}
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chan->vq->vq_ops->kick(chan->vq);
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wait_event(*req->wq, req->status == REQ_STATUS_RCVD);
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size = le32_to_cpu(*(__le32 *) rdata);
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err = p9_deserialize_fcall(rdata, size, *rc, t->extended);
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if (err < 0) {
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P9_DPRINTK(P9_DEBUG_TRANS,
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"9p debug: virtio rpc deserialize returned %d\n", err);
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return err;
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}
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#ifdef CONFIG_NET_9P_DEBUG
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if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
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char buf[150];
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p9_printfcall(buf, sizeof(buf), *rc, t->extended);
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printk(KERN_NOTICE ">>> %p %s\n", t, buf);
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}
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#endif
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if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
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p9_idpool_put(n, chan->tagpool);
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req->status = REQ_STATUS_IDLE;
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return 0;
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}
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static int p9_virtio_probe(struct virtio_device *vdev)
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{
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int err;
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struct virtio_chan *chan;
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int index;
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down(&virtio_9p_lock);
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index = chan_index++;
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chan = &channels[index];
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up(&virtio_9p_lock);
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if (chan_index > MAX_9P_CHAN) {
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printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
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BUG();
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err = -ENOMEM;
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goto fail;
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}
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chan->vdev = vdev;
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/* We expect one virtqueue, for requests. */
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chan->vq = vdev->config->find_vq(vdev, 0, req_done);
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if (IS_ERR(chan->vq)) {
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err = PTR_ERR(chan->vq);
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goto out_free_vq;
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}
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chan->vq->vdev->priv = chan;
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spin_lock_init(&chan->lock);
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sg_init_table(chan->sg, VIRTQUEUE_NUM);
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chan->inuse = false;
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chan->initialized = true;
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return 0;
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out_free_vq:
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vdev->config->del_vq(chan->vq);
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fail:
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down(&virtio_9p_lock);
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chan_index--;
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up(&virtio_9p_lock);
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return err;
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}
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/* This sets up a transport channel for 9p communication. Right now
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* we only match the first available channel, but eventually we couldlook up
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* alternate channels by matching devname versus a virtio_config entry.
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* We use a simple reference count mechanism to ensure that only a single
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* mount has a channel open at a time. */
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static struct p9_trans *
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p9_virtio_create(const char *devname, char *args, int msize,
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unsigned char extended)
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{
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struct p9_trans *trans;
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struct virtio_chan *chan = channels;
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int index = 0;
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down(&virtio_9p_lock);
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while (index < MAX_9P_CHAN) {
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if (chan->initialized && !chan->inuse) {
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chan->inuse = true;
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break;
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} else {
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index++;
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chan = &channels[index];
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}
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}
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up(&virtio_9p_lock);
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if (index >= MAX_9P_CHAN) {
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printk(KERN_ERR "9p: no channels available\n");
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return ERR_PTR(-ENODEV);
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}
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chan->tagpool = p9_idpool_create();
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if (IS_ERR(chan->tagpool)) {
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printk(KERN_ERR "9p: couldn't allocate tagpool\n");
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return ERR_PTR(-ENOMEM);
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}
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p9_idpool_get(chan->tagpool); /* reserve tag 0 */
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chan->max_tag = 0;
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chan->reqs = NULL;
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trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
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if (!trans) {
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printk(KERN_ERR "9p: couldn't allocate transport\n");
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return ERR_PTR(-ENOMEM);
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}
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trans->extended = extended;
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trans->msize = msize;
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trans->close = p9_virtio_close;
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trans->rpc = p9_virtio_rpc;
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trans->priv = chan;
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return trans;
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}
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static void p9_virtio_remove(struct virtio_device *vdev)
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{
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struct virtio_chan *chan = vdev->priv;
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BUG_ON(chan->inuse);
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if (chan->initialized) {
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vdev->config->del_vq(chan->vq);
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chan->initialized = false;
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}
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}
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#define VIRTIO_ID_9P 9
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static struct virtio_device_id id_table[] = {
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{ VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
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{ 0 },
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};
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/* The standard "struct lguest_driver": */
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static struct virtio_driver p9_virtio_drv = {
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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.probe = p9_virtio_probe,
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.remove = p9_virtio_remove,
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};
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static struct p9_trans_module p9_virtio_trans = {
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.name = "virtio",
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.create = p9_virtio_create,
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.maxsize = PAGE_SIZE*16,
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.def = 0,
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};
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/* The standard init function */
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static int __init p9_virtio_init(void)
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{
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int count;
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for (count = 0; count < MAX_9P_CHAN; count++)
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channels[count].initialized = false;
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v9fs_register_trans(&p9_virtio_trans);
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return register_virtio_driver(&p9_virtio_drv);
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}
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static void __exit p9_virtio_cleanup(void)
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{
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unregister_virtio_driver(&p9_virtio_drv);
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}
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module_init(p9_virtio_init);
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module_exit(p9_virtio_cleanup);
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MODULE_DEVICE_TABLE(virtio, id_table);
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MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
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MODULE_DESCRIPTION("Virtio 9p Transport");
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MODULE_LICENSE("GPL");
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