/*
* The Guest 9p transport driver
*
- * This is a trivial pipe-based transport driver based on the lguest console
- * code: we use lguest's DMA mechanism to send bytes out, and register a
- * DMA buffer to receive bytes in. It is assumed to be present and available
- * from the very beginning of boot.
- *
- * This may be have been done by just instaniating another HVC console,
- * but HVC's blocksize of 16 bytes is annoying and painful to performance.
- *
- * A more efficient transport could be built based on the virtio block driver
- * but it requires some changes in the 9p transport model (which are in
- * progress)
+ * This is a block based transport driver based on the lguest block driver
+ * code.
*
*/
/*
#include <linux/virtio.h>
#include <linux/virtio_9p.h>
+#define VIRTQUEUE_NUM 128
+
/* a single mutex to manage channel initialization and attachment */
static DECLARE_MUTEX(virtio_9p_lock);
/* global which tracks highest initialized channel */
static int chan_index;
+#define P9_INIT_MAXTAG 16
+
+#define REQ_STATUS_IDLE 0
+#define REQ_STATUS_SENT 1
+#define REQ_STATUS_RCVD 2
+#define REQ_STATUS_FLSH 3
+
+struct p9_req_t {
+ int status;
+ wait_queue_head_t *wq;
+};
+
/* We keep all per-channel information in a structure.
* This structure is allocated within the devices dev->mem space.
* A pointer to the structure will get put in the transport private.
bool initialized; /* channel is initialized */
bool inuse; /* channel is in use */
- struct virtqueue *in_vq, *out_vq;
+ spinlock_t lock;
+
struct virtio_device *vdev;
+ struct virtqueue *vq;
- /* This is our input buffer, and how much data is left in it. */
- unsigned int in_len;
- char *in, *inbuf;
+ struct p9_idpool *tagpool;
+ struct p9_req_t *reqs;
+ int max_tag;
- wait_queue_head_t wq; /* waitq for buffer */
+ /* Scatterlist: can be too big for stack. */
+ struct scatterlist sg[VIRTQUEUE_NUM];
} channels[MAX_9P_CHAN];
+/* Lookup requests by tag */
+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)
{
return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
}
-static int p9_virtio_write(struct p9_trans *trans, void *buf, int count)
+static void p9_virtio_close(struct p9_trans *trans)
{
- struct virtio_chan *chan = (struct virtio_chan *) trans->priv;
- struct virtqueue *out_vq = chan->out_vq;
- struct scatterlist sg[1];
- unsigned int len;
+ struct virtio_chan *chan = trans->priv;
+ int count;
+ unsigned int flags;
- P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio write (%d)\n", count);
+ 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);
- /* keep it simple - make sure we don't overflow a page */
- if (rest_of_page(buf) < count)
- count = rest_of_page(buf);
+ down(&virtio_9p_lock);
+ chan->inuse = false;
+ up(&virtio_9p_lock);
- sg_init_one(sg, buf, count);
+ kfree(trans);
+}
- /* add_buf wants a token to identify this buffer: we hand it any
- * non-NULL pointer, since there's only ever one buffer. */
- if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) == 0) {
- /* Tell Host to go! */
- out_vq->vq_ops->kick(out_vq);
- /* Chill out until it's done with the buffer. */
- while (!out_vq->vq_ops->get_buf(out_vq, &len))
- cpu_relax();
+static void req_done(struct virtqueue *vq)
+{
+ 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);
+ 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, "9p debug: virtio wrote (%d)\n", count);
-
- /* We're expected to return the amount of data we wrote: all of it. */
- return count;
+ /* In case queue is stopped waiting for more buffers. */
+ spin_unlock_irqrestore(&chan->lock, flags);
}
-/* Create a scatter-gather list representing our input buffer and put it in the
- * queue. */
-static void add_inbuf(struct virtio_chan *chan)
+static int
+pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
+ int count)
{
- struct scatterlist sg[1];
-
- sg_init_one(sg, chan->inbuf, PAGE_SIZE);
+ int s;
+ int index = start;
+
+ while (count) {
+ s = rest_of_page(data);
+ if (s > count)
+ s = count;
+ sg_set_buf(&sg[index++], data, s);
+ count -= s;
+ data += s;
+ BUG_ON(index > limit);
+ }
- /* We should always be able to add one buffer to an empty queue. */
- if (chan->in_vq->vq_ops->add_buf(chan->in_vq, sg, 0, 1, chan->inbuf))
- BUG();
- chan->in_vq->vq_ops->kick(chan->in_vq);
+ return index-start;
}
-static int p9_virtio_read(struct p9_trans *trans, void *buf, int count)
+static int
+p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
{
- struct virtio_chan *chan = (struct virtio_chan *) trans->priv;
- struct virtqueue *in_vq = chan->in_vq;
-
- P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio read (%d)\n", count);
+ 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;
+ }
- /* If we don't have an input queue yet, we can't get input. */
- BUG_ON(!in_vq);
+ rdata = (char *)*rc+sizeof(struct p9_fcall);
- /* No buffer? Try to get one. */
- if (!chan->in_len) {
- chan->in = in_vq->vq_ops->get_buf(in_vq, &chan->in_len);
- if (!chan->in)
- return 0;
+ n = P9_NOTAG;
+ if (tc->id != P9_TVERSION) {
+ n = p9_idpool_get(chan->tagpool);
+ if (n < 0)
+ return -ENOMEM;
}
- /* You want more than we have to give? Well, try wanting less! */
- if (chan->in_len < count)
- count = chan->in_len;
+ spin_lock_irqsave(&chan->lock, flags);
+ req = p9_lookup_tag(chan, n);
+ spin_unlock_irqrestore(&chan->lock, flags);
- /* Copy across to their buffer and increment offset. */
- memcpy(buf, chan->in, count);
- chan->in += count;
- chan->in_len -= count;
+ p9_set_tag(tc, n);
- /* Finished? Re-register buffer so Host will use it again. */
- if (chan->in_len == 0)
- add_inbuf(chan);
+ P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio rpc tag %d\n", n);
- P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio finished read (%d)\n",
- count);
-
- return count;
-}
+ 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);
-/* The poll function is used by 9p transports to determine if there
- * is there is activity available on a particular channel. In our case
- * we use it to wait for a callback from the input routines.
- */
-static unsigned int
-p9_virtio_poll(struct p9_trans *trans, struct poll_table_struct *pt)
-{
- struct virtio_chan *chan = (struct virtio_chan *)trans->priv;
- struct virtqueue *in_vq = chan->in_vq;
- int ret = POLLOUT; /* we can always handle more output */
+ req->status = REQ_STATUS_SENT;
- poll_wait(NULL, &chan->wq, pt);
+ if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, tc)) {
+ P9_DPRINTK(P9_DEBUG_TRANS,
+ "9p debug: virtio rpc add_buf returned failure");
+ return -EIO;
+ }
- /* No buffer? Try to get one. */
- if (!chan->in_len)
- chan->in = in_vq->vq_ops->get_buf(in_vq, &chan->in_len);
+ chan->vq->vq_ops->kick(chan->vq);
- if (chan->in_len)
- ret |= POLLIN;
+ wait_event(*req->wq, req->status == REQ_STATUS_RCVD);
- return ret;
-}
+ size = le32_to_cpu(*(__le32 *) rdata);
-static void p9_virtio_close(struct p9_trans *trans)
-{
- struct virtio_chan *chan = trans->priv;
+ 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;
+ }
- down(&virtio_9p_lock);
- chan->inuse = false;
- up(&virtio_9p_lock);
+#ifdef CONFIG_NET_9P_DEBUG
+ if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+ char buf[150];
- kfree(trans);
-}
+ p9_printfcall(buf, sizeof(buf), *rc, t->extended);
+ printk(KERN_NOTICE ">>> %p %s\n", t, buf);
+ }
+#endif
-static bool p9_virtio_intr(struct virtqueue *q)
-{
- struct virtio_chan *chan = q->vdev->priv;
+ if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
+ p9_idpool_put(n, chan->tagpool);
- P9_DPRINTK(P9_DEBUG_TRANS, "9p poll_wakeup: %p\n", &chan->wq);
- wake_up_interruptible(&chan->wq);
+ req->status = REQ_STATUS_IDLE;
- return true;
+ return 0;
}
-static int p9_virtio_probe(struct virtio_device *dev)
+static int p9_virtio_probe(struct virtio_device *vdev)
{
int err;
struct virtio_chan *chan;
if (chan_index > MAX_9P_CHAN) {
printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
BUG();
- }
-
- chan->vdev = dev;
-
- /* This is the scratch page we use to receive console input */
- chan->inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!chan->inbuf) {
err = -ENOMEM;
goto fail;
}
- /* Find the input queue. */
- dev->priv = chan;
- chan->in_vq = dev->config->find_vq(dev, p9_virtio_intr);
- if (IS_ERR(chan->in_vq)) {
- err = PTR_ERR(chan->in_vq);
- goto free;
- }
+ chan->vdev = vdev;
- chan->out_vq = dev->config->find_vq(dev, NULL);
- if (IS_ERR(chan->out_vq)) {
- err = PTR_ERR(chan->out_vq);
- goto free_in_vq;
+ /* We expect one virtqueue, for requests. */
+ chan->vq = vdev->config->find_vq(vdev, 0, req_done);
+ if (IS_ERR(chan->vq)) {
+ err = PTR_ERR(chan->vq);
+ goto out_free_vq;
}
+ chan->vq->vdev->priv = chan;
+ spin_lock_init(&chan->lock);
- init_waitqueue_head(&chan->wq);
+ sg_init_table(chan->sg, VIRTQUEUE_NUM);
- /* Register the input buffer the first time. */
- add_inbuf(chan);
chan->inuse = false;
chan->initialized = true;
-
return 0;
-free_in_vq:
- dev->config->del_vq(chan->in_vq);
-free:
- kfree(chan->inbuf);
+out_free_vq:
+ vdev->config->del_vq(chan->vq);
fail:
down(&virtio_9p_lock);
chan_index--;
* alternate channels by matching devname versus a virtio_config entry.
* We use a simple reference count mechanism to ensure that only a single
* mount has a channel open at a time. */
-static struct p9_trans *p9_virtio_create(const char *devname, char *args)
+static struct p9_trans *
+p9_virtio_create(const char *devname, char *args, int msize,
+ unsigned char extended)
{
struct p9_trans *trans;
- int index = 0;
struct virtio_chan *chan = channels;
+ int index = 0;
down(&virtio_9p_lock);
while (index < MAX_9P_CHAN) {
up(&virtio_9p_lock);
if (index >= MAX_9P_CHAN) {
- printk(KERN_ERR "9p: virtio: couldn't find a free channel\n");
- return NULL;
+ printk(KERN_ERR "9p: no channels available\n");
+ return ERR_PTR(-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->write = p9_virtio_write;
- trans->read = p9_virtio_read;
+ trans->extended = extended;
+ trans->msize = msize;
trans->close = p9_virtio_close;
- trans->poll = p9_virtio_poll;
+ trans->rpc = p9_virtio_rpc;
trans->priv = chan;
return trans;
}
+static void p9_virtio_remove(struct virtio_device *vdev)
+{
+ struct virtio_chan *chan = vdev->priv;
+
+ BUG_ON(chan->inuse);
+
+ if (chan->initialized) {
+ vdev->config->del_vq(chan->vq);
+ chan->initialized = false;
+ }
+}
+
#define VIRTIO_ID_9P 9
static struct virtio_device_id id_table[] = {
.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,
- .maxsize = PAGE_SIZE,
+ .maxsize = PAGE_SIZE*16,
.def = 0,
};
return register_virtio_driver(&p9_virtio_drv);
}
+static void __exit p9_virtio_cleanup(void)
+{
+ unregister_virtio_driver(&p9_virtio_drv);
+}
+
module_init(p9_virtio_init);
+module_exit(p9_virtio_cleanup);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
projects / linux-flexiantxendom0-3.2.10.git / blobdiff