xen/fb: fix potential memory leak

From: Joe Jin <joe.jin@oracle.com>

This patch fixes a potential memory leak when xenfb connect to
the backend fails.

Thanks for Ian's review and comments.

[v2: reworded the commit message a bit]

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joe Jin <joe.jin@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Made apply to linux-2.6.18-xen.hg.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/drivers/xen/fbfront/xenfb.c b/drivers/xen/fbfront/xenfb.c
index ce2d87a7b18ec7edfa39e40d65bba84c665efdbd..912808a672917df14080f98b102bb203504e0833 100644 (file)
--- a/drivers/xen/fbfront/xenfb.c
+++ b/drivers/xen/fbfront/xenfb.c
@@ -735,23 +735,22 @@ static void xenfb_init_shared_page(struct xenfb_info *info,
 static int xenfb_connect_backend(struct xenbus_device *dev,
                                 struct xenfb_info *info)
 {
-       int ret;
+       int ret, irq;
        struct xenbus_transaction xbt;
 
-       ret = bind_listening_port_to_irqhandler(
+       irq = bind_listening_port_to_irqhandler(
                dev->otherend_id, xenfb_event_handler, 0, "xenfb", info);
-       if (ret < 0) {
-               xenbus_dev_fatal(dev, ret,
+       if (irq < 0) {
+               xenbus_dev_fatal(dev, irq,
                                 "bind_listening_port_to_irqhandler");
-               return ret;
+               return irq;
        }
-       info->irq = ret;
 
  again:
        ret = xenbus_transaction_start(&xbt);
        if (ret) {
                xenbus_dev_fatal(dev, ret, "starting transaction");
-               return ret;
+               goto unbind_irq;
        }
        ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
                            virt_to_mfn(info->page));
@@ -773,15 +772,18 @@ static int xenfb_connect_backend(struct xenbus_device *dev,
                if (ret == -EAGAIN)
                        goto again;
                xenbus_dev_fatal(dev, ret, "completing transaction");
-               return ret;
+               goto unbind_irq;
        }
 
+       info->irq = irq;
        xenbus_switch_state(dev, XenbusStateInitialised);
        return 0;
 
  error_xenbus:
        xenbus_transaction_end(xbt, 1);
        xenbus_dev_fatal(dev, ret, "writing xenstore");
+ unbind_irq:
+       unbind_from_irqhandler(irq, info);
        return ret;
 }