[Devel] [PATCH rh7 v2] ve/drivers: Do not forget to release mismatched device found

[Cyrill Gorcunov]

Upon call of device_destroy_namespace we walk over namespace devices
looking for one which match on both device maj/min and VE itself,
but the thing is that if device belong to another VE we continue
iteration with never released get_device call.

Thus rework device_destroy_namespace (thanks to vdavydov@
for idea) -- pass __match_devt_ns matcher which would
test for namespace inside class_find_device itself.

https://jira.sw.ru/browse/PSBM-34777

Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
CC: Andrey Vagin <avagin at virtuozzo.com>
CC: Vladimir Davydov <vdavydov at virtuozzo.com>
CC: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 drivers/base/core.c |   30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

Index: linux-pcs7.git/drivers/base/core.c
===================================================================
--- linux-pcs7.git.orig/drivers/base/core.c
+++ linux-pcs7.git/drivers/base/core.c
@@ -1836,19 +1836,29 @@ void device_destroy(struct class *class,
 }
 EXPORT_SYMBOL_GPL(device_destroy);
 
-void device_destroy_namespace(struct class *class, dev_t devt, void *ns)
+struct __match_devt_ns_arg {
+	dev_t	devt;
+	void	*ns;
+};
+
+static int __match_devt_ns(struct device *dev, const void *data)
 {
-	struct device *dev = NULL;
+	const struct __match_devt_ns_arg *arg = data;
+
+	return dev->devt == arg->devt &&
+		(!dev->class->namespace ||
+		 dev->class->namespace(dev) == arg->ns);
+}
 
-	for (;;) {
-		dev = class_find_device(class, dev, &devt, __match_devt);
-		if (!dev)
-			break;
-		if (!class->namespace ||
-		    (class->namespace(dev) == ns))
-			break;
-	}
+void device_destroy_namespace(struct class *class, dev_t devt, void *ns)
+{
+	struct __match_devt_ns_arg arg = {
+		.devt	= devt,
+		.ns	= ns,
+	};
+	struct device *dev;
 
+	dev = class_find_device(class, NULL, &arg, __match_devt_ns);
 	if (dev) {
 		put_device(dev);
 		device_unregister(dev);