/*
- * The Guest 9p transport driver
+ * The Virtio 9p transport driver
*
* This is a block based transport driver based on the lguest block driver
* code.
*
- */
-/*
- * Copyright (C) 2007 Eric Van Hensbergen, IBM Corporation
+ * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation
*
* Based on virtio console driver
* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
#include <linux/inet.h>
#include <linux/idr.h>
#include <linux/file.h>
+#include <linux/slab.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
+#include <net/9p/client.h>
#include <net/9p/transport.h>
#include <linux/scatterlist.h>
#include <linux/virtio.h>
/* a single mutex to manage channel initialization and attachment */
static DEFINE_MUTEX(virtio_9p_lock);
-/* global which tracks highest initialized channel */
-static int chan_index;
-
-#define P9_INIT_MAXTAG 16
-
-
-/**
- * enum p9_req_status_t - virtio request status
- * @REQ_STATUS_IDLE: request slot unused
- * @REQ_STATUS_SENT: request sent to server
- * @REQ_STATUS_RCVD: response received from server
- * @REQ_STATUS_FLSH: request has been flushed
- *
- * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
- * but use is actually tracked by the idpool structure which handles tag
- * id allocation.
- *
- */
-
-enum p9_req_status_t {
- REQ_STATUS_IDLE,
- REQ_STATUS_SENT,
- REQ_STATUS_RCVD,
- REQ_STATUS_FLSH,
-};
-
-/**
- * struct p9_req_t - virtio request slots
- * @status: status of this request slot
- * @wq: wait_queue for the client to block on for this request
- *
- * The virtio transport uses an array to track outstanding requests
- * instead of a list. While this may incurr overhead during initial
- * allocation or expansion, it makes request lookup much easier as the
- * tag id is a index into an array. (We use tag+1 so that we can accomodate
- * the -1 tag for the T_VERSION request).
- * This also has the nice effect of only having to allocate wait_queues
- * once, instead of constantly allocating and freeing them. Its possible
- * other resources could benefit from this scheme as well.
- *
- */
-
-struct p9_req_t {
- int status;
- wait_queue_head_t *wq;
-};
/**
* struct virtio_chan - per-instance transport information
* @initialized: whether the channel is initialized
* @inuse: whether the channel is in use
* @lock: protects multiple elements within this structure
+ * @client: client instance
* @vdev: virtio dev associated with this channel
* @vq: virtio queue associated with this channel
- * @tagpool: accounting for tag ids (and request slots)
- * @reqs: array of request slots
- * @max_tag: current number of request_slots allocated
* @sg: scatter gather list which is used to pack a request (protected?)
*
* We keep all per-channel information in a structure.
*
*/
-static struct virtio_chan {
- bool initialized;
+struct virtio_chan {
bool inuse;
spinlock_t lock;
+ struct p9_client *client;
struct virtio_device *vdev;
struct virtqueue *vq;
- struct p9_idpool *tagpool;
- struct p9_req_t *reqs;
- int max_tag;
-
/* Scatterlist: can be too big for stack. */
struct scatterlist sg[VIRTQUEUE_NUM];
-} channels[MAX_9P_CHAN];
-
-/**
- * p9_lookup_tag - Lookup requests by tag
- * @c: virtio channel to lookup tag within
- * @tag: numeric id for transaction
- *
- * this is a simple array lookup, but will grow the
- * request_slots as necessary to accomodate transaction
- * ids which did not previously have a slot.
- *
- * Bugs: there is currently no upper limit on request slots set
- * here, but that should be constrained by the id accounting.
- */
-static struct p9_req_t *p9_lookup_tag(struct virtio_chan *c, u16 tag)
-{
- /* This looks up the original request by tag so we know which
- * buffer to read the data into */
- tag++;
-
- while (tag >= c->max_tag) {
- int old_max = c->max_tag;
- int count;
-
- if (c->max_tag)
- c->max_tag *= 2;
- else
- c->max_tag = P9_INIT_MAXTAG;
-
- c->reqs = krealloc(c->reqs, sizeof(struct p9_req_t)*c->max_tag,
- GFP_ATOMIC);
- if (!c->reqs) {
- printk(KERN_ERR "Couldn't grow tag array\n");
- BUG();
- }
- for (count = old_max; count < c->max_tag; count++) {
- c->reqs[count].status = REQ_STATUS_IDLE;
- c->reqs[count].wq = kmalloc(sizeof(wait_queue_head_t),
- GFP_ATOMIC);
- if (!c->reqs[count].wq) {
- printk(KERN_ERR "Couldn't grow tag array\n");
- BUG();
- }
- init_waitqueue_head(c->reqs[count].wq);
- }
- }
+ int tag_len;
+ /*
+ * tag name to identify a mount Non-null terminated
+ */
+ char *tag;
- return &c->reqs[tag];
-}
+ struct list_head chan_list;
+};
+static struct list_head virtio_chan_list;
/* How many bytes left in this page. */
static unsigned int rest_of_page(void *data)
/**
* p9_virtio_close - reclaim resources of a channel
- * @trans: transport state
+ * @client: client instance
*
* This reclaims a channel by freeing its resources and
* reseting its inuse flag.
*
*/
-static void p9_virtio_close(struct p9_trans *trans)
+static void p9_virtio_close(struct p9_client *client)
{
- struct virtio_chan *chan = trans->priv;
- int count;
- unsigned long flags;
-
- spin_lock_irqsave(&chan->lock, flags);
- p9_idpool_destroy(chan->tagpool);
- for (count = 0; count < chan->max_tag; count++)
- kfree(chan->reqs[count].wq);
- kfree(chan->reqs);
- chan->max_tag = 0;
- spin_unlock_irqrestore(&chan->lock, flags);
+ struct virtio_chan *chan = client->trans;
mutex_lock(&virtio_9p_lock);
- chan->inuse = false;
+ if (chan)
+ chan->inuse = false;
mutex_unlock(&virtio_9p_lock);
-
- kfree(trans);
}
/**
struct virtio_chan *chan = vq->vdev->priv;
struct p9_fcall *rc;
unsigned int len;
- unsigned long flags;
struct p9_req_t *req;
- spin_lock_irqsave(&chan->lock, flags);
+ P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
+
while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) {
- req = p9_lookup_tag(chan, rc->tag);
+ P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
+ P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
+ req = p9_tag_lookup(chan->client, rc->tag);
req->status = REQ_STATUS_RCVD;
- wake_up(req->wq);
+ p9_client_cb(chan->client, req);
}
- /* In case queue is stopped waiting for more buffers. */
- spin_unlock_irqrestore(&chan->lock, flags);
}
/**
return index-start;
}
+/* We don't currently allow canceling of virtio requests */
+static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
+{
+ return 1;
+}
+
/**
- * p9_virtio_rpc - issue a request and wait for a response
- * @t: transport state
- * @tc: &p9_fcall request to transmit
- * @rc: &p9_fcall to put reponse into
+ * p9_virtio_request - issue a request
+ * @client: client instance issuing the request
+ * @req: request to be issued
*
*/
static int
-p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
+p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
{
int in, out;
- int n, err, size;
- struct virtio_chan *chan = t->priv;
- char *rdata;
- struct p9_req_t *req;
- unsigned long flags;
-
- if (*rc == NULL) {
- *rc = kmalloc(sizeof(struct p9_fcall) + t->msize, GFP_KERNEL);
- if (!*rc)
- return -ENOMEM;
- }
-
- rdata = (char *)*rc+sizeof(struct p9_fcall);
-
- n = P9_NOTAG;
- if (tc->id != P9_TVERSION) {
- n = p9_idpool_get(chan->tagpool);
- if (n < 0)
- return -ENOMEM;
- }
-
- spin_lock_irqsave(&chan->lock, flags);
- req = p9_lookup_tag(chan, n);
- spin_unlock_irqrestore(&chan->lock, flags);
+ struct virtio_chan *chan = client->trans;
+ char *rdata = (char *)req->rc+sizeof(struct p9_fcall);
- p9_set_tag(tc, n);
+ P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
- P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio rpc tag %d\n", n);
-
- out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, tc->sdata, tc->size);
- in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata, t->msize);
+ out = pack_sg_list(chan->sg, 0, VIRTQUEUE_NUM, req->tc->sdata,
+ req->tc->size);
+ in = pack_sg_list(chan->sg, out, VIRTQUEUE_NUM-out, rdata,
+ client->msize);
req->status = REQ_STATUS_SENT;
- if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, tc)) {
+ if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) {
P9_DPRINTK(P9_DEBUG_TRANS,
"9p debug: virtio rpc add_buf returned failure");
return -EIO;
chan->vq->vq_ops->kick(chan->vq);
- wait_event(*req->wq, req->status == REQ_STATUS_RCVD);
-
- size = le32_to_cpu(*(__le32 *) rdata);
-
- err = p9_deserialize_fcall(rdata, size, *rc, t->extended);
- if (err < 0) {
- P9_DPRINTK(P9_DEBUG_TRANS,
- "9p debug: virtio rpc deserialize returned %d\n", err);
- return err;
- }
-
-#ifdef CONFIG_NET_9P_DEBUG
- if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
- char buf[150];
-
- p9_printfcall(buf, sizeof(buf), *rc, t->extended);
- printk(KERN_NOTICE ">>> %p %s\n", t, buf);
- }
-#endif
+ P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
+ return 0;
+}
- if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
- p9_idpool_put(n, chan->tagpool);
+static ssize_t p9_mount_tag_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_chan *chan;
+ struct virtio_device *vdev;
- req->status = REQ_STATUS_IDLE;
+ vdev = dev_to_virtio(dev);
+ chan = vdev->priv;
- return 0;
+ return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
}
+static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
+
/**
* p9_virtio_probe - probe for existence of 9P virtio channels
* @vdev: virtio device to probe
*
- * This probes for existing virtio channels. At present only
- * a single channel is in use, so in the future more work may need
- * to be done here.
+ * This probes for existing virtio channels.
*
*/
static int p9_virtio_probe(struct virtio_device *vdev)
{
+ __u16 tag_len;
+ char *tag;
int err;
struct virtio_chan *chan;
- int index;
- mutex_lock(&virtio_9p_lock);
- index = chan_index++;
- chan = &channels[index];
- mutex_unlock(&virtio_9p_lock);
-
- if (chan_index > MAX_9P_CHAN) {
- printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
- BUG();
+ chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
+ if (!chan) {
+ printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n");
err = -ENOMEM;
goto fail;
}
chan->vdev = vdev;
/* We expect one virtqueue, for requests. */
- chan->vq = vdev->config->find_vq(vdev, 0, req_done);
+ chan->vq = virtio_find_single_vq(vdev, req_done, "requests");
if (IS_ERR(chan->vq)) {
err = PTR_ERR(chan->vq);
goto out_free_vq;
sg_init_table(chan->sg, VIRTQUEUE_NUM);
chan->inuse = false;
- chan->initialized = true;
+ if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
+ vdev->config->get(vdev,
+ offsetof(struct virtio_9p_config, tag_len),
+ &tag_len, sizeof(tag_len));
+ } else {
+ err = -EINVAL;
+ goto out_free_vq;
+ }
+ tag = kmalloc(tag_len, GFP_KERNEL);
+ if (!tag) {
+ err = -ENOMEM;
+ goto out_free_vq;
+ }
+ vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
+ tag, tag_len);
+ chan->tag = tag;
+ chan->tag_len = tag_len;
+ err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+ if (err) {
+ kfree(tag);
+ goto out_free_vq;
+ }
+ mutex_lock(&virtio_9p_lock);
+ list_add_tail(&chan->chan_list, &virtio_chan_list);
+ mutex_unlock(&virtio_9p_lock);
return 0;
out_free_vq:
- vdev->config->del_vq(chan->vq);
+ vdev->config->del_vqs(vdev);
+ kfree(chan);
fail:
- mutex_lock(&virtio_9p_lock);
- chan_index--;
- mutex_unlock(&virtio_9p_lock);
return err;
}
/**
* p9_virtio_create - allocate a new virtio channel
+ * @client: client instance invoking this transport
* @devname: string identifying the channel to connect to (unused)
* @args: args passed from sys_mount() for per-transport options (unused)
- * @msize: requested maximum packet size
- * @extended: 9p2000.u enabled flag
*
* This sets up a transport channel for 9p communication. Right now
* we only match the first available channel, but eventually we couldlook up
* We use a simple reference count mechanism to ensure that only a single
* mount has a channel open at a time.
*
- * Bugs: doesn't allow identification of a specific channel
- * to allocate, channels are allocated sequentially. This was
- * a pragmatic decision to get things rolling, but ideally some
- * way of identifying the channel to attach to would be nice
- * if we are going to support multiple channels.
- *
*/
-static struct p9_trans *
-p9_virtio_create(const char *devname, char *args, int msize,
- unsigned char extended)
+static int
+p9_virtio_create(struct p9_client *client, const char *devname, char *args)
{
- struct p9_trans *trans;
- struct virtio_chan *chan = channels;
- int index = 0;
+ struct virtio_chan *chan;
+ int ret = -ENOENT;
+ int found = 0;
mutex_lock(&virtio_9p_lock);
- while (index < MAX_9P_CHAN) {
- if (chan->initialized && !chan->inuse) {
- chan->inuse = true;
- break;
- } else {
- index++;
- chan = &channels[index];
+ list_for_each_entry(chan, &virtio_chan_list, chan_list) {
+ if (!strncmp(devname, chan->tag, chan->tag_len)) {
+ if (!chan->inuse) {
+ chan->inuse = true;
+ found = 1;
+ break;
+ }
+ ret = -EBUSY;
}
}
mutex_unlock(&virtio_9p_lock);
- if (index >= MAX_9P_CHAN) {
+ if (!found) {
printk(KERN_ERR "9p: no channels available\n");
- return ERR_PTR(-ENODEV);
+ return ret;
}
- chan->tagpool = p9_idpool_create();
- if (IS_ERR(chan->tagpool)) {
- printk(KERN_ERR "9p: couldn't allocate tagpool\n");
- return ERR_PTR(-ENOMEM);
- }
- p9_idpool_get(chan->tagpool); /* reserve tag 0 */
- chan->max_tag = 0;
- chan->reqs = NULL;
-
- trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
- if (!trans) {
- printk(KERN_ERR "9p: couldn't allocate transport\n");
- return ERR_PTR(-ENOMEM);
- }
- trans->extended = extended;
- trans->msize = msize;
- trans->close = p9_virtio_close;
- trans->rpc = p9_virtio_rpc;
- trans->priv = chan;
+ client->trans = (void *)chan;
+ client->status = Connected;
+ chan->client = client;
- return trans;
+ return 0;
}
/**
struct virtio_chan *chan = vdev->priv;
BUG_ON(chan->inuse);
+ vdev->config->del_vqs(vdev);
- if (chan->initialized) {
- vdev->config->del_vq(chan->vq);
- chan->initialized = false;
- }
-}
+ mutex_lock(&virtio_9p_lock);
+ list_del(&chan->chan_list);
+ mutex_unlock(&virtio_9p_lock);
+ sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+ kfree(chan->tag);
+ kfree(chan);
-#define VIRTIO_ID_9P 9
+}
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID },
{ 0 },
};
+static unsigned int features[] = {
+ VIRTIO_9P_MOUNT_TAG,
+};
+
/* The standard "struct lguest_driver": */
static struct virtio_driver p9_virtio_drv = {
- .driver.name = KBUILD_MODNAME,
- .driver.owner = THIS_MODULE,
- .id_table = id_table,
- .probe = p9_virtio_probe,
- .remove = p9_virtio_remove,
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = p9_virtio_probe,
+ .remove = p9_virtio_remove,
};
static struct p9_trans_module p9_virtio_trans = {
.name = "virtio",
.create = p9_virtio_create,
+ .close = p9_virtio_close,
+ .request = p9_virtio_request,
+ .cancel = p9_virtio_cancel,
.maxsize = PAGE_SIZE*16,
.def = 0,
.owner = THIS_MODULE,
/* The standard init function */
static int __init p9_virtio_init(void)
{
- int count;
-
- for (count = 0; count < MAX_9P_CHAN; count++)
- channels[count].initialized = false;
+ INIT_LIST_HEAD(&virtio_chan_list);
v9fs_register_trans(&p9_virtio_trans);
return register_virtio_driver(&p9_virtio_drv);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff