RE: [PATCH v3 2/3] drivers: hv: vmbus: add test attributes to debugfs

Expose the test parameters as part of the debugfs channel attributes.
We will control the testing state via these attributes.

Signed-off-by: Branden Bonaby <redacted>
---
Changes in v3:
 - Change call to IS_ERR_OR_NULL, to IS_ERR.

Changes in v2:
 - Move test attributes to debugfs.
 - Wrap test code under #ifdef statements.
 - Add new documentation file under Documentation/ABI/testing.
 - Make commit message reflect the change from from sysfs to debugfs.

 Documentation/ABI/testing/debugfs-hyperv |  21 +++
 MAINTAINERS                              |   1 +
 drivers/hv/vmbus_drv.c                   | 167 +++++++++++++++++++++++
 3 files changed, 189 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-hyperv

diff --git a/Documentation/ABI/testing/debugfs-hyperv

b/Documentation/ABI/testing/debugfs-hyperv
new file mode 100644
index 000000000000..b25f751fafa8

--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-hyperv

@@ -0,0 +1,21 @@
+What:           /sys/kernel/debug/hyperv/<UUID>/fuzz_test_state
+Date:           August 2019
+KernelVersion:  5.3
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing status of a vmbus device, whether its in an ON
+                state or a OFF state

+Users:          Debugging tools
+
+What:           /sys/kernel/debug/hyperv/<UUID>/delay/fuzz_test_buffer_interrupt_delay
+Date:           August 2019
+KernelVersion:  5.3
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing buffer delay value between 0 - 1000

+Users:          Debugging tools
+
+What:           /sys/kernel/debug/hyperv/<UUID>/delay/fuzz_test_message_delay
+Date:           August 2019
+KernelVersion:  5.3
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing message delay value between 0 - 1000

+Users:          Debugging tools

diff --git a/MAINTAINERS b/MAINTAINERS
index e81e60bd7c26..120284a8185f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -7460,6 +7460,7 @@ F:	include/uapi/linux/hyperv.h
 F:	include/asm-generic/mshyperv.h
 F:	tools/hv/
 F:	Documentation/ABI/stable/sysfs-bus-vmbus
+F:	Documentation/ABI/testing/debugfs-hyperv

 HYPERBUS SUPPORT
 M:	Vignesh Raghavendra <vigneshr@ti.com>

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index ebd35fc35290..d2e47f04d172 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c

@@ -919,6 +919,10 @@ static void vmbus_device_release(struct device *device)
 	struct hv_device *hv_dev = device_to_hv_device(device);
 	struct vmbus_channel *channel = hv_dev->channel;

+#ifdef CONFIG_HYPERV_TESTING
+	hv_debug_rm_dev_dir(hv_dev);
+#endif /* CONFIG_HYPERV_TESTING */

+
 	mutex_lock(&vmbus_connection.channel_mutex);
 	hv_process_channel_removal(channel);
 	mutex_unlock(&vmbus_connection.channel_mutex);

@@ -1727,6 +1731,9 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 		pr_err("Unable to register primary channeln");
 		goto err_kset_unregister;
 	}
+#ifdef CONFIG_HYPERV_TESTING
+	hv_debug_add_dev_dir(child_device_obj);
+#endif /* CONFIG_HYPERV_TESTING */

 	return 0;

@@ -2086,6 +2093,159 @@ static void hv_crash_handler(struct pt_regs *regs)
 	hyperv_cleanup();
 };

+#ifdef CONFIG_HYPERV_TESTING
+
+struct dentry *hv_root;
+
+static int hv_debugfs_delay_get(void *data, u64 *val)
+{
+	*val = *(u32 *)data;
+	return 0;
+}
+
+static int hv_debugfs_delay_set(void *data, u64 val)
+{
+	if (val >= 1 && val <= 1000)
+		*(u32 *)data = val;
+	/*Best to not use else statement here since we want
+	 * the delay to remain the same if val > 1000
+	 */

+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(hv_debugfs_delay_fops, hv_debugfs_delay_get,
+			 hv_debugfs_delay_set, "%llu\n");
+