/*
- * 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/file.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>
/* 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
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);
- }
- }
-
- return &c->reqs[tag];
-}
-
-
/* How many bytes left in this page. */
static unsigned int rest_of_page(void *data)
{
*
*/
-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;
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);
- req->status = REQ_STATUS_RCVD;
- wake_up(req->wq);
+ 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);
+ 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
+ * p9_virtio_request - issue a request
* @t: transport state
* @tc: &p9_fcall request to transmit
* @rc: &p9_fcall to put reponse into
*/
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)) {
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
-
- if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
- p9_idpool_put(n, chan->tagpool);
-
- req->status = REQ_STATUS_IDLE;
-
+ P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
return 0;
}
/**
* 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
*
*/
-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;
if (index >= MAX_9P_CHAN) {
printk(KERN_ERR "9p: no channels available\n");
- return ERR_PTR(-ENODEV);
+ return -ENODEV;
}
- 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;
+ chan->client = client;
- return trans;
+ return 0;
}
/**
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,
Code Review / linux-2.6.git / blobdiff