9p: make rpc code common and rework flush code

This code moves the rpc function to the common client base,
reorganizes the flush code to be more simple and stable, and
makes the necessary adjustments to the underlying transports
to adapt to the new structure.

This reduces the overall amount of code duplication between the
transports and should make adding new transports more straightforward.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

5 files changed, 316 insertions, 313 deletions

diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 4fecaabd17b..6a71d906781 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -212,8 +212,7 @@ struct p9_stat *p9_client_stat(struct p9_fid *fid);
 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
 struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset);
 
-struct p9_req_t *p9_tag_alloc(struct p9_client *, u16);
 struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
-void p9_free_req(struct p9_client *, struct p9_req_t *);
+void p9_client_cb(struct p9_client *c, struct p9_req_t *req);
 
 #endif /* NET_9P_CLIENT_H */
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index 3e0f2f6beba..6d5886efb10 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -33,8 +33,8 @@
  * @maxsize: transport provided maximum packet size
  * @def: set if this transport should be considered the default
  * @create: member function to create a new connection on this transport
- * @close: member function to disconnect and close the transport
- * @rpc: member function to issue a request to the transport
+ * @request: member function to issue a request to the transport
+ * @cancel: member function to cancel a request (if it hasn't been sent)
  *
  * This is the basic API for a transport module which is registered by the
  * transport module with the 9P core network module and used by the client
@@ -51,8 +51,8 @@ struct p9_trans_module {
         struct module *owner;
         int (*create)(struct p9_client *, const char *, char *);
         void (*close) (struct p9_client *);
-        int (*rpc) (struct p9_client *t, struct p9_fcall *tc,
-                                                        struct p9_fcall **rc);
+        int (*request) (struct p9_client *, struct p9_req_t *req);
+        int (*cancel) (struct p9_client *, struct p9_req_t *req);
 };
 
 void v9fs_register_trans(struct p9_trans_module *m);
diff --git a/net/9p/client.c b/net/9p/client.c
index f2d07ef9e6a..29934febecd 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -55,6 +55,9 @@ static const match_table_t tokens = {
         {Opt_err, NULL},
 };
 
+static int
+p9_client_rpc(struct p9_client *c, struct p9_fcall *tc, struct p9_fcall **rc);
+
 /**
  * v9fs_parse_options - parse mount options into session structure
  * @options: options string passed from mount
@@ -269,6 +272,36 @@ static void p9_tag_cleanup(struct p9_client *c)
 }
 
 /**
+ * p9_client_flush - flush (cancel) a request
+ * c: client state
+ * req: request to cancel
+ *
+ * This sents a flush for a particular requests and links
+ * the flush request to the original request.  The current
+ * code only supports a single flush request although the protocol
+ * allows for multiple flush requests to be sent for a single request.
+ *
+ */
+
+static int p9_client_flush(struct p9_client *c, struct p9_req_t *req)
+{
+        struct p9_fcall *tc, *rc = NULL;
+        int err;
+
+        P9_DPRINTK(P9_DEBUG_9P, "client %p tag %d\n", c, req->tc->tag);
+
+        tc = p9_create_tflush(req->tc->tag);
+        if (IS_ERR(tc))
+                return PTR_ERR(tc);
+
+        err = p9_client_rpc(c, tc, &rc);
+
+        /* we don't free anything here because RPC isn't complete */
+
+        return err;
+}
+
+/**
  * p9_free_req - free a request and clean-up as necessary
  * c: client state
  * r: request to release
@@ -289,6 +322,224 @@ void p9_free_req(struct p9_client *c, struct p9_req_t *r)
         }
 }
 
+/**
+ * p9_client_cb - call back from transport to client
+ * c: client state
+ * req: request received
+ *
+ */
+void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
+{
+        struct p9_req_t *other_req;
+        unsigned long flags;
+
+        P9_DPRINTK(P9_DEBUG_MUX, ": %d\n", req->tc->tag);
+
+        if (req->status == REQ_STATUS_ERROR)
+                wake_up(req->wq);
+
+        if (req->tc->id == P9_TFLUSH) { /* flush receive path */
+                P9_DPRINTK(P9_DEBUG_MUX, "flush: %d\n", req->tc->tag);
+                spin_lock_irqsave(&c->lock, flags);
+                other_req = p9_tag_lookup(c, req->tc->params.tflush.oldtag);
+                if (other_req->flush_tag != req->tc->tag) /* stale flush */
+                        spin_unlock_irqrestore(&c->lock, flags);
+                else {
+                        BUG_ON(other_req->status != REQ_STATUS_FLSH);
+                        other_req->status = REQ_STATUS_FLSHD;
+                        spin_unlock_irqrestore(&c->lock, flags);
+                        wake_up(other_req->wq);
+                }
+                p9_free_req(c, req);
+        } else {                                /* normal receive path */
+                P9_DPRINTK(P9_DEBUG_MUX, "normal: %d\n", req->tc->tag);
+                spin_lock_irqsave(&c->lock, flags);
+                if (req->status != REQ_STATUS_FLSHD)
+                        req->status = REQ_STATUS_RCVD;
+                req->flush_tag = P9_NOTAG;
+                spin_unlock_irqrestore(&c->lock, flags);
+                wake_up(req->wq);
+                P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
+        }
+}
+EXPORT_SYMBOL(p9_client_cb);
+
+/**
+ * p9_client_rpc - issue a request and wait for a response
+ * @c: client session
+ * @tc: &p9_fcall request to transmit
+ * @rc: &p9_fcall to put reponse into
+ *
+ * Returns 0 on success, error code on failure
+ */
+
+static int
+p9_client_rpc(struct p9_client *c, struct p9_fcall *tc, struct p9_fcall **rc)
+{
+        int tag, err, size;
+        char *rdata;
+        struct p9_req_t *req;
+        unsigned long flags;
+        int sigpending;
+        int flushed = 0;
+
+        P9_DPRINTK(P9_DEBUG_9P, "client %p tc %p rc %p\n", c, tc, rc);
+
+        if (c->status != Connected)
+                return -EIO;
+
+        if (signal_pending(current)) {
+                sigpending = 1;
+                clear_thread_flag(TIF_SIGPENDING);
+        } else
+                sigpending = 0;
+
+        tag = P9_NOTAG;
+        if (tc->id != P9_TVERSION) {
+                tag = p9_idpool_get(c->tagpool);
+                if (tag < 0)
+                        return -ENOMEM;
+        }
+
+        req = p9_tag_alloc(c, tag);
+
+        /* if this is a flush request, backlink flush request now to
+         * avoid race conditions later. */
+        if (tc->id == P9_TFLUSH) {
+                struct p9_req_t *other_req =
+                                p9_tag_lookup(c, tc->params.tflush.oldtag);
+                if (other_req->status == REQ_STATUS_FLSH)
+                        other_req->flush_tag = tag;
+        }
+
+        p9_set_tag(tc, tag);
+
+        /*
+         * if client passed in a pre-allocated response fcall struct
+         * then we just use that, otherwise we allocate one.
+         */
+
+        if (rc == NULL)
+                req->rc = NULL;
+        else
+                req->rc = *rc;
+        if (req->rc == NULL) {
+                req->rc = kmalloc(sizeof(struct p9_fcall) + c->msize,
+                                                                GFP_KERNEL);
+                if (!req->rc) {
+                        err = -ENOMEM;
+                        p9_idpool_put(tag, c->tagpool);
+                        p9_free_req(c, req);
+                        goto reterr;
+                }
+                *rc = req->rc;
+        }
+
+        rdata = (char *)req->rc+sizeof(struct p9_fcall);
+
+        req->tc = tc;
+        P9_DPRINTK(P9_DEBUG_9P, "request: tc: %p rc: %p\n", req->tc, req->rc);
+
+        err = c->trans_mod->request(c, req);
+        if (err < 0) {
+                c->status = Disconnected;
+                goto reterr;
+        }
+
+        /* if it was a flush we just transmitted, return our tag */
+        if (tc->id == P9_TFLUSH)
+                return 0;
+again:
+        P9_DPRINTK(P9_DEBUG_9P, "wait %p tag: %d\n", req->wq, tag);
+        err = wait_event_interruptible(*req->wq,
+                                                req->status >= REQ_STATUS_RCVD);
+        P9_DPRINTK(P9_DEBUG_9P, "wait %p tag: %d returned %d (flushed=%d)\n",
+                                                req->wq, tag, err, flushed);
+
+        if (req->status == REQ_STATUS_ERROR) {
+                P9_DPRINTK(P9_DEBUG_9P, "req_status error %d\n", req->t_err);
+                err = req->t_err;
+        } else if (err == -ERESTARTSYS && flushed) {
+                P9_DPRINTK(P9_DEBUG_9P, "flushed - going again\n");
+                goto again;
+        } else if (req->status == REQ_STATUS_FLSHD) {
+                P9_DPRINTK(P9_DEBUG_9P, "flushed - erestartsys\n");
+                err = -ERESTARTSYS;
+        }
+
+        if ((err == -ERESTARTSYS) && (c->status == Connected) && (!flushed)) {
+                P9_DPRINTK(P9_DEBUG_9P, "flushing\n");
+                spin_lock_irqsave(&c->lock, flags);
+                if (req->status == REQ_STATUS_SENT)
+                        req->status = REQ_STATUS_FLSH;
+                spin_unlock_irqrestore(&c->lock, flags);
+                sigpending = 1;
+                flushed = 1;
+                clear_thread_flag(TIF_SIGPENDING);
+
+                if (c->trans_mod->cancel(c, req)) {
+                        err = p9_client_flush(c, req);
+                        if (err == 0)
+                                goto again;
+                }
+        }
+
+        if (sigpending) {
+                spin_lock_irqsave(&current->sighand->siglock, flags);
+                recalc_sigpending();
+                spin_unlock_irqrestore(&current->sighand->siglock, flags);
+        }
+
+        if (err < 0)
+                goto reterr;
+
+        size = le32_to_cpu(*(__le32 *) rdata);
+
+        err = p9_deserialize_fcall(rdata, size, req->rc, c->dotu);
+        if (err < 0) {
+                P9_DPRINTK(P9_DEBUG_9P,
+                        "9p debug: client rpc deserialize returned %d\n", err);
+                goto reterr;
+        }
+
+#ifdef CONFIG_NET_9P_DEBUG
+        if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
+                char buf[150];
+
+                p9_printfcall(buf, sizeof(buf), req->rc, c->dotu);
+                printk(KERN_NOTICE ">>> %p %s\n", c, buf);
+        }
+#endif
+
+        if (req->rc->id == P9_RERROR) {
+                int ecode = req->rc->params.rerror.errno;
+                struct p9_str *ename = &req->rc->params.rerror.error;
+
+                P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
+                                                                ename->str);
+
+                if (c->dotu)
+                        err = -ecode;
+
+                if (!err) {
+                        err = p9_errstr2errno(ename->str, ename->len);
+
+                        /* string match failed */
+                        if (!err) {
+                                PRINT_FCALL_ERROR("unknown error", req->rc);
+                                err = -ESERVERFAULT;
+                        }
+                }
+        } else
+                err = 0;
+
+reterr:
+        p9_free_req(c, req);
+
+        P9_DPRINTK(P9_DEBUG_9P, "returning %d\n", err);
+        return err;
+}
+
 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 {
         int err;
@@ -339,20 +590,6 @@ static void p9_fid_destroy(struct p9_fid *fid)
         kfree(fid);
 }
 
-/**
- * p9_client_rpc - sends 9P request and waits until a response is available.
- *      The function can be interrupted.
- * @c: client data
- * @tc: request to be sent
- * @rc: pointer where a pointer to the response is stored
- */
-int
-p9_client_rpc(struct p9_client *c, struct p9_fcall *tc,
-        struct p9_fcall **rc)
-{
-        return c->trans_mod->rpc(c, tc, rc);
-}
-
 struct p9_client *p9_client_create(const char *dev_name, char *options)
 {
         int err, n;
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 627e3f097fc..6bfc013f8b6 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -174,44 +174,6 @@ static void p9_mux_poll_stop(struct p9_conn *m)
         spin_unlock_irqrestore(&p9_poll_lock, flags);
 }
 
-static void p9_conn_rpc_cb(struct p9_client *, struct p9_req_t *);
-
-static void p9_mux_flush_cb(struct p9_client *client, struct p9_req_t *freq)
-{
-        struct p9_conn *m = client->trans;
-        struct p9_req_t *req;
-
-        P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
-                freq->tc, freq->rc, freq->t_err,
-                freq->tc->params.tflush.oldtag);
-
-        req = p9_tag_lookup(client, freq->tc->params.tflush.oldtag);
-        if (req) {
-                req->status = REQ_STATUS_FLSHD;
-                list_del(&req->req_list);
-                p9_conn_rpc_cb(client, req);
-        }
-
-        p9_free_req(client, freq);
-}
-
-static void p9_conn_rpc_cb(struct p9_client *client, struct p9_req_t *req)
-{
-        P9_DPRINTK(P9_DEBUG_MUX, "req %p\n", req);
-
-        if (req->tc->id == P9_TFLUSH) { /* flush callback */
-                P9_DPRINTK(P9_DEBUG_MUX, "flush req %p\n", req);
-                p9_mux_flush_cb(client, req);
-        } else {                        /* normal wakeup path */
-                P9_DPRINTK(P9_DEBUG_MUX, "normal req %p\n", req);
-                if (!req->t_err && (req->status == REQ_STATUS_FLSHD ||
-                                 req->status == REQ_STATUS_FLSH))
-                        req->t_err = -ERESTARTSYS;
-
-                wake_up(req->wq);
-        }
-}
-
 /**
  * p9_conn_cancel - cancel all pending requests with error
  * @m: mux data
@@ -222,11 +184,12 @@ static void p9_conn_rpc_cb(struct p9_client *client, struct p9_req_t *req)
 void p9_conn_cancel(struct p9_conn *m, int err)
 {
         struct p9_req_t *req, *rtmp;
+        unsigned long flags;
         LIST_HEAD(cancel_list);
 
         P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
         m->err = err;
-        spin_lock(&m->client->lock);
+        spin_lock_irqsave(&m->client->lock, flags);
         list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
                 req->status = REQ_STATUS_ERROR;
                 if (!req->t_err)
@@ -239,44 +202,12 @@ void p9_conn_cancel(struct p9_conn *m, int err)
                         req->t_err = err;
                 list_move(&req->req_list, &cancel_list);
         }
-        spin_unlock(&m->client->lock);
+        spin_unlock_irqrestore(&m->client->lock, flags);
 
         list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
                 list_del(&req->req_list);
-                p9_conn_rpc_cb(m->client, req);
-        }
-}
-
-static void process_request(struct p9_conn *m, struct p9_req_t *req)
-{
-        int ecode;
-        struct p9_str *ename;
-
-        if (!req->t_err && req->rc->id == P9_RERROR) {
-                ecode = req->rc->params.rerror.errno;
-                ename = &req->rc->params.rerror.error;
-
-                P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
-                                                                ename->str);
-
-                if (m->client->dotu)
-                        req->t_err = -ecode;
-
-                if (!req->t_err) {
-                        req->t_err = p9_errstr2errno(ename->str, ename->len);
-
-                        /* string match failed */
-                        if (!req->t_err) {
-                                PRINT_FCALL_ERROR("unknown error", req->rc);
-                                req->t_err = -ESERVERFAULT;
-                        }
-                }
-        } else if (req->tc && req->rc->id != req->tc->id + 1) {
-                P9_DPRINTK(P9_DEBUG_ERROR,
-                                "fcall mismatch: expected %d, got %d\n",
-                                req->tc->id + 1, req->rc->id);
-                if (!req->t_err)
-                        req->t_err = -EIO;
+                P9_DPRINTK(P9_DEBUG_ERROR, "call back req %p\n", req);
+                p9_client_cb(m->client, req);
         }
 }
 
@@ -421,41 +352,13 @@ static void p9_read_work(struct work_struct *work)
         /* not an else because some packets (like clunk) have no payload */
         if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */
                 P9_DPRINTK(P9_DEBUG_MUX, "got new packet\n");
-                m->rbuf = (char *)m->req->rc + sizeof(struct p9_fcall);
-                err = p9_deserialize_fcall(m->rbuf, m->rsize, m->req->rc,
-                                                        m->client->dotu);
-                if (err < 0) {
-                        m->req = NULL;
-                        goto error;
-                }
-
-#ifdef CONFIG_NET_9P_DEBUG
-                if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
-                        char buf[150];
-
-                        p9_printfcall(buf, sizeof(buf), m->req->rc,
-                                m->client->dotu);
-                        printk(KERN_NOTICE ">>> %p %s\n", m, buf);
-                }
-#endif
 
-                P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
-                                        m->req->rc->id, m->req->rc->tag);
+                list_del(&m->req->req_list);
+                p9_client_cb(m->client, m->req);
 
                 m->rbuf = NULL;
                 m->rpos = 0;
                 m->rsize = 0;
-
-                if (m->req->status != REQ_STATUS_FLSH) {
-                        list_del(&m->req->req_list);
-                        m->req->status = REQ_STATUS_RCVD;
-                }
-
-                process_request(m, m->req);
-
-                if (m->req->status != REQ_STATUS_FLSH)
-                        p9_conn_rpc_cb(m->client, m->req);
-
                 m->req = NULL;
         }
 
@@ -741,57 +644,41 @@ static void p9_poll_mux(struct p9_conn *m)
 }
 
 /**
- * p9_send_request - send 9P request
+ * p9_fd_request - send 9P request
  * The function can sleep until the request is scheduled for sending.
  * The function can be interrupted. Return from the function is not
- * a guarantee that the request is sent successfully. Can return errors
- * that can be retrieved by PTR_ERR macros.
+ * a guarantee that the request is sent successfully.
  *
- * @m: mux data
- * @tc: request to be sent
+ * @client: client instance
+ * @req: request to be sent
  *
  */
 
-static struct p9_req_t *p9_send_request(struct p9_conn *m, struct p9_fcall *tc)
+static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 {
-        int tag;
         int n;
-        struct p9_req_t *req;
+        struct p9_trans_fd *ts = client->trans;
+        struct p9_conn *m = ts->conn;
 
         P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
-                tc, tc->id);
+                req->tc, req->tc->id);
         if (m->err < 0)
-                return ERR_PTR(m->err);
-
-        tag = P9_NOTAG;
-        if (tc->id != P9_TVERSION) {
-                tag = p9_idpool_get(m->client->tagpool);
-                if (tag < 0)
-                        return ERR_PTR(-ENOMEM);
-        }
-
-        p9_set_tag(tc, tag);
-
-        req = p9_tag_alloc(m->client, tag);
+                return m->err;
 
 #ifdef CONFIG_NET_9P_DEBUG
         if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
                 char buf[150];
 
-                p9_printfcall(buf, sizeof(buf), tc, m->client->dotu);
+                p9_printfcall(buf, sizeof(buf), req->tc, client->dotu);
                 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
         }
 #endif
 
-        req->tag = tag;
-        req->tc = tc;
-        req->rc = NULL;
-        req->t_err = 0;
         req->status = REQ_STATUS_UNSENT;
 
-        spin_lock(&m->client->lock);
+        spin_lock(&client->lock);
         list_add_tail(&req->req_list, &m->unsent_req_list);
-        spin_unlock(&m->client->lock);
+        spin_unlock(&client->lock);
 
         if (test_and_clear_bit(Wpending, &m->wsched))
                 n = POLLOUT;
@@ -801,17 +688,20 @@ static struct p9_req_t *p9_send_request(struct p9_conn *m, struct p9_fcall *tc)
         if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
                 queue_work(p9_mux_wq, &m->wq);
 
-        return req;
+        return 0;
 }
 
-static int
-p9_mux_flush_request(struct p9_conn *m, struct p9_req_t *req)
+static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req)
 {
-        struct p9_fcall *fc;
-        struct p9_req_t *rreq, *rptr;
+        struct p9_trans_fd *ts = client->trans;
+        struct p9_conn *m = ts->conn;
 
         P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
 
+        spin_lock(&client->lock);
+        list_del(&req->req_list);
+        spin_unlock(&client->lock);
+
         /* if a response was received for a request, do nothing */
         if (req->rc || req->t_err) {
                 P9_DPRINTK(P9_DEBUG_MUX,
@@ -819,104 +709,15 @@ p9_mux_flush_request(struct p9_conn *m, struct p9_req_t *req)
                 return 0;
         }
 
-        req->status = REQ_STATUS_FLSH;
-
-        spin_lock(&m->client->lock);
-        /* if the request is not sent yet, just remove it from the list */
-        list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
-                if (rreq->tag == req->tag) {
-                        P9_DPRINTK(P9_DEBUG_MUX,
-                           "mux %p req %p request is not sent yet\n", m, req);
-                        list_del(&rreq->req_list);
-                        req->status = REQ_STATUS_FLSHD;
-                        spin_unlock(&m->client->lock);
-                        p9_conn_rpc_cb(m->client, req);
-                        return 0;
-                }
+        if (req->status == REQ_STATUS_UNSENT) {
+                req->status = REQ_STATUS_FLSHD;
+                return 0;
         }
-        spin_unlock(&m->client->lock);
 
-        clear_thread_flag(TIF_SIGPENDING);
-        fc = p9_create_tflush(req->tag);
-        p9_send_request(m, fc);
         return 1;
 }
 
 /**
- * p9_fd_rpc- sends 9P request and waits until a response is available.
- *      The function can be interrupted.
- * @client: client instance
- * @tc: request to be sent
- * @rc: pointer where a pointer to the response is stored
- *
- */
-
-int
-p9_fd_rpc(struct p9_client *client, struct p9_fcall *tc, struct p9_fcall **rc)
-{
-        struct p9_trans_fd *p = client->trans;
-        struct p9_conn *m = p->conn;
-        int err, sigpending;
-        unsigned long flags;
-        struct p9_req_t *req;
-
-        if (rc)
-                *rc = NULL;
-
-        sigpending = 0;
-        if (signal_pending(current)) {
-                sigpending = 1;
-                clear_thread_flag(TIF_SIGPENDING);
-        }
-
-        req = p9_send_request(m, tc);
-        if (IS_ERR(req)) {
-                err = PTR_ERR(req);
-                P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
-                return err;
-        }
-
-        err = wait_event_interruptible(*req->wq, req->rc != NULL ||
-                                                                req->t_err < 0);
-        if (req->t_err < 0)
-                err = req->t_err;
-
-        if (err == -ERESTARTSYS && client->status == Connected
-                                                        && m->err == 0) {
-                if (p9_mux_flush_request(m, req)) {
-                        /* wait until we get response of the flush message */
-                        do {
-                                clear_thread_flag(TIF_SIGPENDING);
-                                err = wait_event_interruptible(*req->wq,
-                                        req->rc || req->t_err);
-                        } while (!req->rc && !req->t_err &&
-                                        err == -ERESTARTSYS &&
-                                        client->status == Connected && !m->err);
-
-                        err = -ERESTARTSYS;
-                }
-                sigpending = 1;
-        }
-
-        if (sigpending) {
-                spin_lock_irqsave(&current->sighand->siglock, flags);
-                recalc_sigpending();
-                spin_unlock_irqrestore(&current->sighand->siglock, flags);
-        }
-
-        if (rc)
-                *rc = req->rc;
-        else
-                kfree(req->rc);
-
-        p9_free_req(client, req);
-        if (err > 0)
-                err = -EIO;
-
-        return err;
-}
-
-/**
  * parse_options - parse mount options into session structure
  * @options: options string passed from mount
  * @opts: transport-specific structure to parse options into
@@ -1243,7 +1044,8 @@ static struct p9_trans_module p9_tcp_trans = {
         .def = 1,
         .create = p9_fd_create_tcp,
         .close = p9_fd_close,
-        .rpc = p9_fd_rpc,
+        .request = p9_fd_request,
+        .cancel = p9_fd_cancel,
         .owner = THIS_MODULE,
 };
 
@@ -1253,7 +1055,8 @@ static struct p9_trans_module p9_unix_trans = {
         .def = 0,
         .create = p9_fd_create_unix,
         .close = p9_fd_close,
-        .rpc = p9_fd_rpc,
+        .request = p9_fd_request,
+        .cancel = p9_fd_cancel,
         .owner = THIS_MODULE,
 };
 
@@ -1263,7 +1066,8 @@ static struct p9_trans_module p9_fd_trans = {
         .def = 0,
         .create = p9_fd_create,
         .close = p9_fd_close,
-        .rpc = p9_fd_rpc,
+        .request = p9_fd_request,
+        .cancel = p9_fd_cancel,
         .owner = THIS_MODULE,
 };
 
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index e18de14c30d..2d7781ec663 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -126,17 +126,16 @@ 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);
+        P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
+
         while ((rc = chan->vq->vq_ops->get_buf(chan->vq, &len)) != NULL) {
+                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);
-                req->status = REQ_STATUS_RCVD;
-                wake_up(req->wq);
+                p9_client_cb(chan->client, req);
         }
-        /* In case queue is stopped waiting for more buffers. */
-        spin_unlock_irqrestore(&chan->lock, flags);
 }
 
 /**
@@ -173,8 +172,14 @@ pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
         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
@@ -182,44 +187,22 @@ pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
  */
 
 static int
-p9_virtio_rpc(struct p9_client *c, 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 = c->trans;
-        char *rdata;
-        struct p9_req_t *req;
-        unsigned long flags;
-
-        if (*rc == NULL) {
-                *rc = kmalloc(sizeof(struct p9_fcall) + c->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(c->tagpool);
-                if (n < 0)
-                        return -ENOMEM;
-        }
-
-        spin_lock_irqsave(&chan->lock, flags);
-        req = p9_tag_alloc(c, n);
-        spin_unlock_irqrestore(&chan->lock, flags);
-
-        p9_set_tag(tc, n);
+        struct virtio_chan *chan = client->trans;
+        char *rdata = (char *)req->rc+sizeof(struct p9_fcall);
 
-        P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio rpc tag %d\n", n);
+        P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\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, c->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;
@@ -227,28 +210,7 @@ p9_virtio_rpc(struct p9_client *c, struct p9_fcall *tc, struct p9_fcall **rc)
 
         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, c->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, c->dotu);
-                printk(KERN_NOTICE ">>> %p %s\n", c, buf);
-        }
-#endif
-
-        p9_free_req(c, req);
-
+        P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request kicked\n");
         return 0;
 }
 
@@ -394,7 +356,8 @@ static struct p9_trans_module p9_virtio_trans = {
         .name = "virtio",
         .create = p9_virtio_create,
         .close = p9_virtio_close,
-        .rpc = p9_virtio_rpc,
+        .request = p9_virtio_request,
+        .cancel = p9_virtio_cancel,
         .maxsize = PAGE_SIZE*16,
         .def = 0,
         .owner = THIS_MODULE,