PCI: hv: Don't leak buffer in hv_pci_onchannelcallback()

BugLink: http://bugs.launchpad.net/bugs/1616677

We don't free buffer on several code paths in hv_pci_onchannelcallback(),
put kfree() to the end of the function to fix the issue.  Direct { kfree();
return; } can now be replaced with a simple 'break';
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jake Oshins <jakeo@microsoft.com>
(cherry picked from commit 60fcdac8)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>

drivers/pci/host/pci-hyperv.c

@@ -1661,10 +1661,8 @@ static void hv_pci_onchannelcallback(void *context)
 		 * All incoming packets must be at least as large as a
 		 * response.
 		 */
-		if (bytes_recvd <= sizeof(struct pci_response)) {
-			kfree(buffer);
-			return;
-		}
+		if (bytes_recvd <= sizeof(struct pci_response))
+			break;
 		desc = (struct vmpacket_descriptor *)buffer;
 
 		switch (desc->type) {
@@ -1679,8 +1677,7 @@ static void hv_pci_onchannelcallback(void *context)
 			comp_packet->completion_func(comp_packet->compl_ctxt,
 						     response,
 						     bytes_recvd);
-			kfree(buffer);
-			return;
+			break;
 
 		case VM_PKT_DATA_INBAND:
 
@@ -1729,6 +1726,8 @@ static void hv_pci_onchannelcallback(void *context)
 		}
 		break;
 	}
+
+	kfree(buffer);
 }
 
 /**