Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1bab88b2 authored by Latchesar Ionkov's avatar Latchesar Ionkov Committed by Eric Van Hensbergen
Browse files

net/9p: handle correctly interrupted 9P requests 



Currently the 9p code crashes when a operation is interrupted, i.e. for
example when the user presses ^C while reading from a file.

This patch fixes the code that is responsible for interruption and flushing
of 9P operations.

Signed-off-by: default avatarLatchesar Ionkov <lucho@ionkov.net>
parent 742b11a7

include/net/9p/client.h

+0 −1
Original line number Diff line number Diff line
@@ -98,7 +98,6 @@ enum p9_req_status_t { 
struct p9_req_t {

	int status;

	int t_err;

	u16 flush_tag;

	wait_queue_head_t *wq;

	struct p9_fcall *tc;

	struct p9_fcall *rc;

net/9p/client.c

+19 −55
Original line number Diff line number Diff line
@@ -203,7 +203,6 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag) 
	p9pdu_reset(req->tc);

	p9pdu_reset(req->rc);



	req->flush_tag = 0;

	req->tc->tag = tag-1;

	req->status = REQ_STATUS_ALLOC;
@@ -324,36 +323,10 @@ static void p9_free_req(struct p9_client *c, struct p9_req_t *r) 
 */

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, " tag %d\n", req->tc->tag);



	if (req->status == REQ_STATUS_ERROR)

		wake_up(req->wq);



	if (req->flush_tag) { 			/* flush receive path */

		P9_DPRINTK(P9_DEBUG_9P, "<<< RFLUSH %d\n", req->tc->tag);

		spin_lock_irqsave(&c->lock, flags);

		other_req = p9_tag_lookup(c, req->flush_tag);

		if (other_req->status != REQ_STATUS_FLSH) /* stale flush */

			spin_unlock_irqrestore(&c->lock, flags);

		else {

			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: tag %d\n", req->tc->tag);

		spin_lock_irqsave(&c->lock, flags);

		if (req->status != REQ_STATUS_FLSHD)

			req->status = REQ_STATUS_RCVD;

		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);



/**
@@ -486,9 +459,15 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq) 
	if (IS_ERR(req))

		return PTR_ERR(req);



	req->flush_tag = oldtag;



	/* we don't free anything here because RPC isn't complete */

	/* if we haven't received a response for oldreq,

	   remove it from the list. */

	spin_lock(&c->lock);

	if (oldreq->status == REQ_STATUS_FLSH)

		list_del(&oldreq->req_list);

	spin_unlock(&c->lock);



	p9_free_req(c, req);

	return 0;

}
@@ -509,7 +488,6 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) 
	struct p9_req_t *req;

	unsigned long flags;

	int sigpending;

	int flushed = 0;



	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
@@ -546,42 +524,28 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) 
		goto reterr;

	}



	/* if it was a flush we just transmitted, return our tag */

	if (type == P9_TFLUSH)

		return req;

again:

	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);

	err = wait_event_interruptible(*req->wq,

						req->status >= REQ_STATUS_RCVD);

	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d (flushed=%d)\n",

						req->wq, tag, err, flushed);

	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",

						req->wq, tag, err);



	if (req->status == REQ_STATUS_ERROR) {

		P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);

		err = req->t_err;

	} else if (err == -ERESTARTSYS && flushed) {

		P9_DPRINTK(P9_DEBUG_MUX, "flushed - going again\n");

		goto again;

	} else if (req->status == REQ_STATUS_FLSHD) {

		P9_DPRINTK(P9_DEBUG_MUX, "flushed - erestartsys\n");

		err = -ERESTARTSYS;

	}



	if ((err == -ERESTARTSYS) && (c->status == Connected) && (!flushed)) {

	if ((err == -ERESTARTSYS) && (c->status == Connected)) {

		P9_DPRINTK(P9_DEBUG_MUX, "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 (c->trans_mod->cancel(c, req))

			p9_client_flush(c, req);



		/* if we received the response anyway, don't signal error */

		if (req->status == REQ_STATUS_RCVD)

			err = 0;

	}



	if (sigpending) {

net/9p/trans_fd.c

+9 −5
Original line number Diff line number Diff line
@@ -213,8 +213,8 @@ static void p9_conn_cancel(struct p9_conn *m, int err) 
	spin_unlock_irqrestore(&m->client->lock, flags);



	list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {

		list_del(&req->req_list);

		P9_DPRINTK(P9_DEBUG_ERROR, "call back req %p\n", req);

		list_del(&req->req_list);

		p9_client_cb(m->client, req);

	}

}
@@ -336,7 +336,8 @@ static void p9_read_work(struct work_struct *work) 
			"mux %p pkt: size: %d bytes tag: %d\n", m, n, tag);



		m->req = p9_tag_lookup(m->client, tag);

		if (!m->req) {

		if (!m->req || (m->req->status != REQ_STATUS_SENT &&

					m->req->status != REQ_STATUS_FLSH)) {

			P9_DPRINTK(P9_DEBUG_ERROR, "Unexpected packet tag %d\n",

								 tag);

			err = -EIO;
@@ -361,10 +362,11 @@ static void p9_read_work(struct work_struct *work) 
	if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */

		P9_DPRINTK(P9_DEBUG_TRANS, "got new packet\n");

		spin_lock(&m->client->lock);

		if (m->req->status != REQ_STATUS_ERROR)

			m->req->status = REQ_STATUS_RCVD;

		list_del(&m->req->req_list);

		spin_unlock(&m->client->lock);

		p9_client_cb(m->client, m->req);



		m->rbuf = NULL;

		m->rpos = 0;

		m->rsize = 0;
@@ -454,6 +456,7 @@ static void p9_write_work(struct work_struct *work) 
		req = list_entry(m->unsent_req_list.next, struct p9_req_t,

			       req_list);

		req->status = REQ_STATUS_SENT;

		P9_DPRINTK(P9_DEBUG_TRANS, "move req %p\n", req);

		list_move_tail(&req->req_list, &m->req_list);



		m->wbuf = req->tc->sdata;
@@ -683,12 +686,13 @@ static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req) 
	P9_DPRINTK(P9_DEBUG_TRANS, "client %p req %p\n", client, req);



	spin_lock(&client->lock);

	list_del(&req->req_list);



	if (req->status == REQ_STATUS_UNSENT) {

		list_del(&req->req_list);

		req->status = REQ_STATUS_FLSHD;

		ret = 0;

	}

	} else if (req->status == REQ_STATUS_SENT)

		req->status = REQ_STATUS_FLSH;



	spin_unlock(&client->lock);

net/9p/trans_rdma.c

+1 −0
Original line number Diff line number Diff line
@@ -295,6 +295,7 @@ handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma, 
		goto err_out;



	req->rc = c->rc;

	req->status = REQ_STATUS_RCVD;

	p9_client_cb(client, req);



	return;

net/9p/trans_virtio.c

+1 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ static void req_done(struct virtqueue *vq) 
		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;

		p9_client_cb(chan->client, req);

	}

}