---

yaml
---
r: 360325
b: refs/heads/master
c: a260624
h: refs/heads/master
i:
  360323: eaceeba
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 02cde50b7ea74557d32ff778c73809322445ccd2
+refs/heads/master: a26062416ef8add48f16fbadded2b5f6fb84d024

trunk/drivers/md/dm-ioctl.c

@@ -1414,6 +1414,22 @@ static int table_status(struct dm_ioctl *param, size_t param_size)
 	return 0;
 }
 
+static bool buffer_test_overflow(char *result, unsigned maxlen)
+{
+	return !maxlen || strlen(result) + 1 >= maxlen;
+}
+
+/*
+ * Process device-mapper dependent messages.
+ * Returns a number <= 1 if message was processed by device mapper.
+ * Returns 2 if message should be delivered to the target.
+ */
+static int message_for_md(struct mapped_device *md, unsigned argc, char **argv,
+			  char *result, unsigned maxlen)
+{
+	return 2;
+}
+
 /*
  * Pass a message to the target that's at the supplied device offset.
  */
@@ -1425,6 +1441,8 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
 	struct dm_table *table;
 	struct dm_target *ti;
 	struct dm_target_msg *tmsg = (void *) param + param->data_start;
+	size_t maxlen;
+	char *result = get_result_buffer(param, param_size, &maxlen);
 
 	md = find_device(param);
 	if (!md)
@@ -1448,6 +1466,10 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
 		goto out_argv;
 	}
 
+	r = message_for_md(md, argc, argv, result, maxlen);
+	if (r <= 1)
+		goto out_argv;
+
 	table = dm_get_live_table(md);
 	if (!table)
 		goto out_argv;
@@ -1473,7 +1495,18 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
  out_argv:
 	kfree(argv);
  out:
-	param->data_size = 0;
+	if (r >= 0)
+		__dev_status(md, param);
+
+	if (r == 1) {
+		param->flags |= DM_DATA_OUT_FLAG;
+		if (buffer_test_overflow(result, maxlen))
+			param->flags |= DM_BUFFER_FULL_FLAG;
+		else
+			param->data_size = param->data_start + strlen(result) + 1;
+		r = 0;
+	}
+
 	dm_put(md);
 	return r;
 }
@@ -1653,6 +1686,7 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
 	param->flags &= ~DM_BUFFER_FULL_FLAG;
 	param->flags &= ~DM_UEVENT_GENERATED_FLAG;
 	param->flags &= ~DM_SECURE_DATA_FLAG;
+	param->flags &= ~DM_DATA_OUT_FLAG;
 
 	/* Ignores parameters */
 	if (cmd == DM_REMOVE_ALL_CMD ||

trunk/include/uapi/linux/dm-ioctl.h

@@ -336,4 +336,9 @@ enum {
  */
 #define DM_SECURE_DATA_FLAG		(1 << 15) /* In */
 
+/*
+ * If set, a message generated output data.
+ */
+#define DM_DATA_OUT_FLAG		(1 << 16) /* Out */
+
 #endif				/* _LINUX_DM_IOCTL_H */