[PATCH v3] kcov, usbip: collect coverage from vhci_rx_loop

[Andrey Konovalov <andreyknvl@xxxxxxxxxx>]

From: Nazime Hande Harputluoglu <handeharputlu@xxxxxxxxxx>

Add kcov_remote_start()/kcov_remote_stop() annotations to the
vhci_rx_loop() function, which is responsible for parsing USB/IP packets
coming into USB/IP client.

Since vhci_rx_loop() threads are spawned per vhci_hcd device instance, the
common kcov handle is used for kcov_remote_start()/stop() annotations
(see Documentation/dev-tools/kcov.rst for details). As the result kcov
can now be used to collect coverage from vhci_rx_loop() threads.

Signed-off-by: Nazime Hande Harputluoglu <handeharputlu@xxxxxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---

Changes v2->v3:
- Fix build without KCOV enabled.

---
 drivers/usb/usbip/usbip_common.h | 4 ++++
 drivers/usb/usbip/vhci_rx.c      | 7 +++++++
 drivers/usb/usbip/vhci_sysfs.c   | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h
index 8be857a4fa13..0906182011d6 100644
--- a/drivers/usb/usbip/usbip_common.h
+++ b/drivers/usb/usbip/usbip_common.h
@@ -277,6 +277,10 @@ struct usbip_device {
 		void (*reset)(struct usbip_device *);
 		void (*unusable)(struct usbip_device *);
 	} eh_ops;
+
+#ifdef CONFIG_KCOV
+	u64 kcov_handle;
+#endif
 };
 
 #define kthread_get_run(threadfn, data, namefmt, ...)			   \
diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c
index 266024cbb64f..68ec0aa64f69 100644
--- a/drivers/usb/usbip/vhci_rx.c
+++ b/drivers/usb/usbip/vhci_rx.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2003-2008 Takahiro Hirofuchi
  */
 
+#include <linux/kcov.h>
 #include <linux/kthread.h>
 #include <linux/slab.h>
 
@@ -261,7 +262,13 @@ int vhci_rx_loop(void *data)
 		if (usbip_event_happened(ud))
 			break;
 
+#ifdef CONFIG_KCOV
+		kcov_remote_start_common(ud->kcov_handle);
+#endif
 		vhci_rx_pdu(ud);
+#ifdef CONFIG_KCOV
+		kcov_remote_stop();
+#endif
 	}
 
 	return 0;
diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c
index be37aec250c2..e167b8a445ad 100644
--- a/drivers/usb/usbip/vhci_sysfs.c
+++ b/drivers/usb/usbip/vhci_sysfs.c
@@ -4,6 +4,7 @@
  * Copyright (C) 2015-2016 Nobuo Iwata
  */
 
+#include <linux/kcov.h>
 #include <linux/kthread.h>
 #include <linux/file.h>
 #include <linux/net.h>
@@ -383,6 +384,9 @@ static ssize_t attach_store(struct device *dev, struct device_attribute *attr,
 	vdev->ud.sockfd     = sockfd;
 	vdev->ud.tcp_socket = socket;
 	vdev->ud.status     = VDEV_ST_NOTASSIGNED;
+#ifdef CONFIG_KCOV
+	vdev->ud.kcov_handle = kcov_common_handle();
+#endif
 
 	spin_unlock(&vdev->ud.lock);
 	spin_unlock_irqrestore(&vhci->lock, flags);
-- 
2.29.0.rc1.297.gfa9743e501-goog