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>

1 files changed, 36 insertions, 232 deletions

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 627e3f097fc5..6bfc013f8b6f 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,
 };