Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e2735b7720320b68590ca2b32b78ca91213931b2
Commit:     e2735b7720320b68590ca2b32b78ca91213931b2
Parent:     043aba403e9958c6526c9279b63919273cb09c13
Author:     Eric Van Hensbergen <[EMAIL PROTECTED]>
AuthorDate: Wed Feb 6 19:25:58 2008 -0600
Committer:  Eric Van Hensbergen <[EMAIL PROTECTED]>
CommitDate: Wed Feb 6 19:25:58 2008 -0600

    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 <[EMAIL PROTECTED]>
---
 include/net/9p/transport.h |    2 +-
 net/9p/client.c            |   34 +++---
 net/9p/trans_virtio.c      |  344 +++++++++++++++++++++++++++-----------------
 3 files changed, 228 insertions(+), 152 deletions(-)

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 @@ 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 {
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 @@ 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;
 
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 42eea5f..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 @@ 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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