9p: drop broken unused error path from p9_conn_create()
Tejun Heo [Mon, 13 Oct 2008 23:45:20 +0000 (18:45 -0500)]
Post p9_fd_poll() error path which checks m->poll_waddr[i] for PTR_ERR
value has the following problems.

* It's completely unused.  Error value is set iff NULL @wait_address
  has been specified to p9_pollwait() which is guaranteed not to
  happen.

* It dereferences @m after deallocating it (introduced by 571ffeaf and
  spotted by Raja R Harinath.

* It returned the wrong value on error.  It should return
  poll_waddr[i] but it returnes poll_waddr (introduced by 571ffeaf).

* p9_mux_poll_stop() doesn't handle PTR_ERR value.  It will try to
  operate on the PTR_ERR value as if it's a normal pointer and cause
  oops.

As the error path is bogus in the first place, there's no reason to
hold onto it.  Kill it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Raja R Harinath <harinath@hurrynot.org>

net/9p/trans_fd.c

index 6bfc013..c07f2ab 100644 (file)
@@ -540,12 +540,6 @@ p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
                return;
        }
 
-       if (!wait_address) {
-               P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
-               pwait->wait_addr = ERR_PTR(-EIO);
-               return;
-       }
-
        pwait->conn = m;
        pwait->wait_addr = wait_address;
        init_waitqueue_func_entry(&pwait->wait, p9_pollwake);
@@ -561,7 +555,7 @@ p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 
 static struct p9_conn *p9_conn_create(struct p9_client *client)
 {
-       int i, n;
+       int n;
        struct p9_conn *m;
 
        P9_DPRINTK(P9_DEBUG_MUX, "client %p msize %d\n", client, client->msize);
@@ -590,15 +584,6 @@ static struct p9_conn *p9_conn_create(struct p9_client *client)
                set_bit(Wpending, &m->wsched);
        }
 
-       for (i = 0; i < ARRAY_SIZE(m->poll_wait); i++) {
-               if (IS_ERR(m->poll_wait[i].wait_addr)) {
-                       p9_mux_poll_stop(m);
-                       kfree(m);
-                       /* return the error code */
-                       return (void *)m->poll_wait[i].wait_addr;
-               }
-       }
-
        return m;
 }