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>
diff --git a/net/9p/client.c b/net/9p/client.c
index 781d89a..dd43a82 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -203,7 +203,6 @@
p9pdu_reset(req->tc);
p9pdu_reset(req->rc);
- req->flush_tag = 0;
req->tc->tag = tag-1;
req->status = REQ_STATUS_ALLOC;
@@ -324,35 +323,9 @@
*/
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);
- }
+ wake_up(req->wq);
+ P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
EXPORT_SYMBOL(p9_client_cb);
@@ -486,9 +459,15 @@
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 @@
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 @@
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) {