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: Latchesar Ionkov <lucho@ionkov.net>

1 files changed, 9 insertions, 5 deletions

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index c613ed08a5e..a2a1814c7a8 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -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);