xen/fb: fix potential memory leak

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>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
index f92313d33e27a0990e54fd68a8b3951234c1ab99..95bbd0a1e5dadcb754f77c14ff089c5acd9a06d2 100644 (file)
--- a/drivers/video/xen-fbfront.c
+++ b/drivers/video/xen-fbfront.c
@@ -562,26 +562,24 @@ 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, evtchn;
+       int ret, evtchn, irq;
        struct xenbus_transaction xbt;
 
        ret = xenbus_alloc_evtchn(dev, &evtchn);
        if (ret)
                return ret;
-       ret = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
+       irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
                                        0, dev->devicetype, info);
-       if (ret < 0) {
+       if (irq < 0) {
                xenbus_free_evtchn(dev, evtchn);
                xenbus_dev_fatal(dev, ret, "bind_evtchn_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));
@@ -603,15 +601,18 @@ 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;
        }
 
        xenbus_switch_state(dev, XenbusStateInitialised);
+       info->irq = irq;
        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;
 }