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Commit 044c7768 authored by Eric Van Hensbergen's avatar Eric Van Hensbergen
Browse files

9p: eliminate callback complexity 



The current trans_fd rpc mechanisms use a dynamic callback mechanism which
introduces a lot of complexity which only accomodates a single special case.
This patch removes much of that complexity in favor of a simple exception
mechanism to deal with flushes.

Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent 21c00368

net/9p/trans_fd.c

+66 −83
Original line number Diff line number Diff line
@@ -105,9 +105,6 @@ enum { 
	Flushed,

};



struct p9_req;

typedef void (*p9_conn_req_callback)(struct p9_req *req, void *a);



/**

 * struct p9_req - fd mux encoding of an rpc transaction

 * @lock: protects req_list
@@ -115,8 +112,6 @@ typedef void (*p9_conn_req_callback)(struct p9_req *req, void *a); 
 * @tcall: request &p9_fcall structure

 * @rcall: response &p9_fcall structure

 * @err: error state

 * @cb: callback for when response is received

 * @cba: argument to pass to callback

 * @flush: flag to indicate RPC has been flushed

 * @req_list: list link for higher level objects to chain requests

 * @m: connection this request was issued on
@@ -130,8 +125,6 @@ struct p9_req { 
	struct p9_fcall *tcall;

	struct p9_fcall *rcall;

	int err;

	p9_conn_req_callback cb;

	void *cba;

	int flush;

	struct list_head req_list;

	struct p9_conn *m;
@@ -231,6 +224,65 @@ static void p9_mux_poll_stop(struct p9_conn *m) 
	spin_unlock_irqrestore(&p9_poll_lock, flags);

}



static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)

{

	p9_mux_put_tag(m, req->tag);

	kfree(req);

}



static void p9_conn_rpc_cb(struct p9_req *req);



static void p9_mux_flush_cb(struct p9_req *freq)

{

	int tag;

	struct p9_conn *m = freq->m;

	struct p9_req *req, *rreq, *rptr;



	P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,

		freq->tcall, freq->rcall, freq->err,

		freq->tcall->params.tflush.oldtag);



	spin_lock(&m->lock);

	tag = freq->tcall->params.tflush.oldtag;

	req = NULL;

	list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {

		if (rreq->tag == tag) {

			req = rreq;

			list_del(&req->req_list);

			break;

		}

	}

	spin_unlock(&m->lock);



	if (req) {

		spin_lock(&req->lock);

		req->flush = Flushed;

		spin_unlock(&req->lock);



		p9_conn_rpc_cb(req);

	}



	kfree(freq->tcall);

	kfree(freq->rcall);

	p9_mux_free_request(m, freq);

}



static void p9_conn_rpc_cb(struct p9_req *req)

{

	P9_DPRINTK(P9_DEBUG_MUX, "req %p\n", req);



	if (req->tcall->id == P9_TFLUSH) { /* flush callback */

		P9_DPRINTK(P9_DEBUG_MUX, "flush req %p\n", req);

		p9_mux_flush_cb(req);

	} else {			/* normal wakeup path */

		P9_DPRINTK(P9_DEBUG_MUX, "normal req %p\n", req);

		if (req->flush != None && !req->err)

			req->err = -ERESTARTSYS;



		wake_up(&req->wqueue);

	}

}



/**

 * p9_conn_cancel - cancel all pending requests with error

 * @m: mux data
@@ -259,10 +311,7 @@ void p9_conn_cancel(struct p9_conn *m, int err) 
		if (!req->err)

			req->err = err;



		if (req->cb)

			(*req->cb) (req, req->cba);

		else

			kfree(req->rcall);

		p9_conn_rpc_cb(req);

	}

}
@@ -472,12 +521,8 @@ static void p9_read_work(struct work_struct *work) 
			req->rcall = rcall;

			process_request(m, req);



			if (req->flush != Flushing) {

				if (req->cb)

					(*req->cb) (req, req->cba);

				else

					kfree(req->rcall);

			}

			if (req->flush != Flushing)

				p9_conn_rpc_cb(req);

		} else {

			if (err >= 0 && rcall->id != P9_RFLUSH)

				P9_DPRINTK(P9_DEBUG_ERROR,
@@ -786,14 +831,10 @@ static void p9_poll_mux(struct p9_conn *m) 
 *

 * @m: mux data

 * @tc: request to be sent

 * @cb: callback function to call when response is received

 * @cba: parameter to pass to the callback function

 *

 */



static struct p9_req *p9_send_request(struct p9_conn *m,

					  struct p9_fcall *tc,

					  p9_conn_req_callback cb, void *cba)

static struct p9_req *p9_send_request(struct p9_conn *m, struct p9_fcall *tc)

{

	int n;

	struct p9_req *req;
@@ -835,8 +876,6 @@ static struct p9_req *p9_send_request(struct p9_conn *m, 
	req->tcall = tc;

	req->rcall = NULL;

	req->err = 0;

	req->cb = cb;

	req->cba = cba;

	req->flush = None;



	spin_lock(&m->lock);
@@ -854,51 +893,6 @@ static struct p9_req *p9_send_request(struct p9_conn *m, 
	return req;

}



static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)

{

	p9_mux_put_tag(m, req->tag);

	kfree(req);

}



static void p9_mux_flush_cb(struct p9_req *freq, void *a)

{

	int tag;

	struct p9_conn *m;

	struct p9_req *req, *rreq, *rptr;



	m = a;

	P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,

		freq->tcall, freq->rcall, freq->err,

		freq->tcall->params.tflush.oldtag);



	spin_lock(&m->lock);

	tag = freq->tcall->params.tflush.oldtag;

	req = NULL;

	list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {

		if (rreq->tag == tag) {

			req = rreq;

			list_del(&req->req_list);

			break;

		}

	}

	spin_unlock(&m->lock);



	if (req) {

		spin_lock(&req->lock);

		req->flush = Flushed;

		spin_unlock(&req->lock);



		if (req->cb)

			(*req->cb) (req, req->cba);

		else

			kfree(req->rcall);

	}



	kfree(freq->tcall);

	kfree(freq->rcall);

	p9_mux_free_request(m, freq);

}



static int

p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)

{
@@ -928,8 +922,7 @@ p9_mux_flush_request(struct p9_conn *m, struct p9_req *req) 
			list_del(&rreq->req_list);

			req->flush = Flushed;

			spin_unlock(&m->lock);

			if (req->cb)

				(*req->cb) (req, req->cba);

			p9_conn_rpc_cb(req);

			return 0;

		}

	}
@@ -937,20 +930,10 @@ p9_mux_flush_request(struct p9_conn *m, struct p9_req *req) 


	clear_thread_flag(TIF_SIGPENDING);

	fc = p9_create_tflush(req->tag);

	p9_send_request(m, fc, p9_mux_flush_cb, m);

	p9_send_request(m, fc);

	return 1;

}



static void p9_conn_rpc_cb(struct p9_req *req, void *a)

{

	P9_DPRINTK(P9_DEBUG_MUX, "req %p arg %p\n", req, a);



	if (req->flush != None && !req->err)

		req->err = -ERESTARTSYS;



	wake_up(&req->wqueue);

}



/**

 * p9_fd_rpc- sends 9P request and waits until a response is available.

 *	The function can be interrupted.
@@ -978,7 +961,7 @@ p9_fd_rpc(struct p9_client *client, struct p9_fcall *tc, struct p9_fcall **rc) 
		clear_thread_flag(TIF_SIGPENDING);

	}



	req = p9_send_request(m, tc, p9_conn_rpc_cb, NULL);

	req = p9_send_request(m, tc);

	if (IS_ERR(req)) {

		err = PTR_ERR(req);

		P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);