Commit e2735b77 authored by Eric Van Hensbergen's avatar Eric Van Hensbergen Committed by Eric Van Hensbergen

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: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent 043aba40
......@@ -40,7 +40,7 @@ struct p9_trans {
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 {
......
......@@ -51,7 +51,7 @@ p9_client_rpc(struct p9_client *c, struct p9_fcall *tc,
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 @@ struct p9_client *p9_client_create(struct p9_trans *trans, int msize,
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 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
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 @@ struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
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 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
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 @@ clunk_fid:
goto error;
}
p9_client_rpc(clnt->conn, tc, &rc);
p9_client_rpc(clnt, tc, &rc);
error:
kfree(tc);
......@@ -356,7 +356,7 @@ int p9_client_open(struct p9_fid *fid, int mode)
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 @@ int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
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 @@ int p9_client_clunk(struct p9_fid *fid)
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 @@ int p9_client_remove(struct p9_fid *fid)
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 @@ int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
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 @@ int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count)
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 @@ p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset, u32 count)
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 @@ p9_client_uwrite(struct p9_fid *fid, const char __user *data, u64 offset,
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 @@ struct p9_stat *p9_client_stat(struct p9_fid *fid)
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 @@ int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
goto done;
}
err = p9_client_rpc(clnt->conn, tc, &rc);
err = p9_client_rpc(clnt, tc, &rc);
done:
kfree(tc);
......@@ -847,7 +847,7 @@ struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset)
goto error;
}
err = p9_client_rpc(clnt->conn, tc, &rc);
err = p9_client_rpc(clnt, tc, &rc);
if (err)
goto error;
......
/*
* 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 @@ static struct virtio_chan {
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)
{
......@@ -86,128 +132,163 @@ static unsigned int rest_of_page(void *data)
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;
/* Only use the rpc mechanism for now */
return count;
}
P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio write (%d)\n", count);
static int p9_virtio_read(struct p9_trans *trans, void *buf, int count)
{
/* Only use the rpc mechanism for now */
return 0;
}
/* keep it simple - make sure we don't overflow a page */
if (rest_of_page(buf) < count)
count = rest_of_page(buf);
/* 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)
{
/* Only use the rpc mechanism for now */
return 0;
}
sg_init_one(sg, buf, count);
static void p9_virtio_close(struct p9_trans *trans)
{
struct virtio_chan *chan = trans->priv;
int count;
unsigned int flags;
/* 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();
}
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);
P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio wrote (%d)\n", count);
down(&virtio_9p_lock);
chan->inuse = false;
up(&virtio_9p_lock);
/* We're expected to return the amount of data we wrote: all of it. */
return count;
kfree(trans);
}
/* Create a scatter-gather list representing our input buffer and put it in the
* queue. */
static void add_inbuf(struct virtio_chan *chan)
static void req_done(struct virtqueue *vq)
{
struct scatterlist sg[1];
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);
}
/* In case queue is stopped waiting for more buffers. */
spin_unlock_irqrestore(&chan->lock, flags);
}
sg_init_one(sg, chan->inbuf, PAGE_SIZE);
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();
}
/* 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,
int msize, int dotu)
{
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) + 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;
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;
}
/* You want more than we have to give? Well, try wanting less! */
if (chan->in_len < count)
count = chan->in_len;
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);
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);
return count;
}
req->status = REQ_STATUS_SENT;
/* 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 */
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;
}
poll_wait(NULL, &chan->wq, pt);
chan->vq->vq_ops->kick(chan->vq);
/* No buffer? Try to get one. */
if (!chan->in_len)
chan->in = in_vq->vq_ops->get_buf(in_vq, &chan->in_len);
wait_event(*req->wq, req->status == REQ_STATUS_RCVD);
if (chan->in_len)
ret |= POLLIN;
size = le32_to_cpu(*(__le32 *) rdata);
return ret;
}
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;
}
static void p9_virtio_close(struct p9_trans *trans)
{
struct virtio_chan *chan = trans->priv;
#ifdef CONFIG_NET_9P_DEBUG
if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
char buf[150];
down(&virtio_9p_lock);
chan->inuse = false;
up(&virtio_9p_lock);
p9_printfcall(buf, sizeof(buf), *rc, dotu);
printk(KERN_NOTICE ">>> %p %s\n", t, buf);
}
#endif
kfree(trans);
}
if (n != P9_NOTAG && p9_idpool_check(n, chan->tagpool))
p9_idpool_put(n, chan->tagpool);
static void p9_virtio_intr(struct virtqueue *q)
{
struct virtio_chan *chan = q->vdev->priv;
req->status = REQ_STATUS_IDLE;
P9_DPRINTK(P9_DEBUG_TRANS, "9p poll_wakeup: %p\n", &chan->wq);
wake_up_interruptible(&chan->wq);
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;
......@@ -221,44 +302,29 @@ static int p9_virtio_probe(struct virtio_device *dev)
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;
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;
/* 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--;
......@@ -274,8 +340,8 @@ fail:
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) {
......@@ -290,9 +356,18 @@ static struct p9_trans *p9_virtio_create(const char *devname, char *args)
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) {
......@@ -304,6 +379,7 @@ static struct p9_trans *p9_virtio_create(const char *devname, char *args)
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 virtio_driver p9_virtio_drv = {
static struct p9_trans_module p9_virtio_trans = {
.name = "virtio",
.create = p9_virtio_create,
.maxsize = PAGE_SIZE,
.maxsize = PAGE_SIZE*16,
.def = 0,
};
......
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