9p: block-based virtio client
This replaces the console-based virto client with a block-based
client using a single request queue.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index adbcafe..f9f362e 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -40,7 +40,7 @@
void (*close) (struct p9_trans *);
unsigned int (*poll)(struct p9_trans *, struct poll_table_struct *);
int (*rpc) (struct p9_trans *t, struct p9_fcall *tc,
- struct p9_fcall **rc);
+ struct p9_fcall **rc, int msize, int dotu);
};
struct p9_trans_module {
diff --git a/net/9p/client.c b/net/9p/client.c
index b0d08c2..433b307 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -51,7 +51,7 @@
struct p9_fcall **rc)
{
if (c->trans->rpc)
- return c->trans->rpc(c->trans, tc, rc);
+ return c->trans->rpc(c->trans, tc, rc, c->msize, c->dotu);
else
return p9_conn_rpc(c->conn, tc, rc);
}
@@ -99,7 +99,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -191,7 +191,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -236,7 +236,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -287,7 +287,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err) {
if (rc && rc->id == P9_RWALK)
goto clunk_fid;
@@ -322,7 +322,7 @@
goto error;
}
- p9_client_rpc(clnt->conn, tc, &rc);
+ p9_client_rpc(clnt, tc, &rc);
error:
kfree(tc);
@@ -356,7 +356,7 @@
goto done;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto done;
@@ -395,7 +395,7 @@
goto done;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto done;
@@ -428,7 +428,7 @@
goto done;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto done;
@@ -460,7 +460,7 @@
goto done;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto done;
@@ -502,7 +502,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -559,7 +559,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -613,7 +613,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -677,7 +677,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -748,7 +748,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
@@ -790,7 +790,7 @@
goto done;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
done:
kfree(tc);
@@ -847,7 +847,7 @@
goto error;
}
- err = p9_client_rpc(clnt->conn, tc, &rc);
+ err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 42eea5fe..0f59022 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -1,17 +1,8 @@
/*
* 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.
*
*/
/*
@@ -55,11 +46,25 @@
#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.
@@ -68,16 +73,57 @@
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_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)
{
@@ -86,83 +132,14 @@
static int p9_virtio_write(struct p9_trans *trans, void *buf, int count)
{
- struct virtio_chan *chan = (struct virtio_chan *) trans->priv;
- struct virtqueue *out_vq = chan->out_vq;
- struct scatterlist sg[1];
- unsigned int len;
-
- P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio write (%d)\n", count);
-
- /* keep it simple - make sure we don't overflow a page */
- if (rest_of_page(buf) < count)
- count = rest_of_page(buf);
-
- sg_init_one(sg, buf, count);
-
- /* 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();
- }
-
- 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. */
+ /* Only use the rpc mechanism for now */
return count;
}
-/* Create a scatter-gather list representing our input buffer and put it in the
- * queue. */
-static void add_inbuf(struct virtio_chan *chan)
-{
- struct scatterlist sg[1];
-
- sg_init_one(sg, chan->inbuf, PAGE_SIZE);
-
- /* 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);
-}
-
static int p9_virtio_read(struct p9_trans *trans, void *buf, int count)
{
- 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);
-
- /* If we don't have an input queue yet, we can't get input. */
- BUG_ON(!in_vq);
-
- /* 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;
- }
-
- /* You want more than we have to give? Well, try wanting less! */
- if (chan->in_len < count)
- count = chan->in_len;
-
- /* Copy across to their buffer and increment offset. */
- memcpy(buf, chan->in, count);
- chan->in += count;
- chan->in_len -= count;
-
- /* 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 finished read (%d)\n",
- count);
-
- return count;
+ /* Only use the rpc mechanism for now */
+ return 0;
}
/* The poll function is used by 9p transports to determine if there
@@ -172,25 +149,23 @@
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 */
-
- poll_wait(NULL, &chan->wq, pt);
-
- /* 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_len)
- ret |= POLLIN;
-
- return ret;
+ /* Only use the rpc mechanism for now */
+ return 0;
}
static void p9_virtio_close(struct p9_trans *trans)
{
struct virtio_chan *chan = trans->priv;
+ int count;
+ unsigned int 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);
down(&virtio_9p_lock);
chan->inuse = false;
@@ -199,15 +174,121 @@
kfree(trans);
}
-static void p9_virtio_intr(struct virtqueue *q)
+static void req_done(struct virtqueue *vq)
{
- struct virtio_chan *chan = q->vdev->priv;
+ struct virtio_chan *chan = vq->vdev->priv;
+ struct p9_fcall *rc;
+ unsigned int len;
+ unsigned long flags;
+ struct p9_req_t *req;
- P9_DPRINTK(P9_DEBUG_TRANS, "9p poll_wakeup: %p\n", &chan->wq);
- wake_up_interruptible(&chan->wq);
+ 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);
+ }
+ /* In case queue is stopped waiting for more buffers. */
+ spin_unlock_irqrestore(&chan->lock, flags);
}
-static int p9_virtio_probe(struct virtio_device *dev)
+static int
+pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
+ int count)
+{
+ 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;
+ if (index > limit)
+ BUG();
+ }
+
+ return index-start;
+}
+
+static int
+p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc,
+ int msize, int dotu)
+{
+ 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) + msize, GFP_KERNEL);
+ if (!*rc)
+ return -ENOMEM;
+ }
+
+ rdata = (char *)*rc+sizeof(struct p9_fcall);
+
+ spin_lock_irqsave(&chan->lock, flags);
+ n = P9_NOTAG;
+ if (tc->id != P9_TVERSION) {
+ n = p9_idpool_get(chan->tagpool);
+ if (n < 0)
+ return -ENOMEM;
+ }
+
+ req = p9_lookup_tag(chan, n);
+ spin_unlock_irqrestore(&chan->lock, flags);
+
+ p9_set_tag(tc, 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, msize);
+
+ req->status = REQ_STATUS_SENT;
+
+ 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;
+ }
+
+ 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, dotu);
+ 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, dotu);
+ 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;
+
+ return 0;
+}
+
+static int p9_virtio_probe(struct virtio_device *vdev)
{
int err;
struct virtio_chan *chan;
@@ -221,44 +302,29 @@
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, 0, p9_virtio_intr);
- if (IS_ERR(chan->in_vq)) {
- err = PTR_ERR(chan->in_vq);
- goto free;
+ chan->vdev = vdev;
+
+ /* 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);
- chan->out_vq = dev->config->find_vq(dev, 1, NULL);
- if (IS_ERR(chan->out_vq)) {
- err = PTR_ERR(chan->out_vq);
- goto free_in_vq;
- }
+ sg_init_table(chan->sg, VIRTQUEUE_NUM);
- init_waitqueue_head(&chan->wq);
-
- /* 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--;
@@ -274,8 +340,8 @@
static struct p9_trans *p9_virtio_create(const char *devname, char *args)
{
struct p9_trans *trans;
- int index = 0;
struct virtio_chan *chan = channels;
+ int index = 0;
down(&virtio_9p_lock);
while (index < MAX_9P_CHAN) {
@@ -290,10 +356,19 @@
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");
@@ -304,6 +379,7 @@
trans->read = p9_virtio_read;
trans->close = p9_virtio_close;
trans->poll = p9_virtio_poll;
+ trans->rpc = p9_virtio_rpc;
trans->priv = chan;
return trans;
@@ -327,7 +403,7 @@
static struct p9_trans_module p9_virtio_trans = {
.name = "virtio",
.create = p9_virtio_create,
- .maxsize = PAGE_SIZE,
+ .maxsize = PAGE_SIZE*16,
.def = 0,
};