[PATCH v2 2/5] HID: hidraw: Introduce hidraw_instance() helper

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Several drivers and subsystem helpers need to determine the minor number
of the hidraw node associated with an underlying HID device. Currently
they access internal driver data and cast the hidraw pointer directly,
requiring drivers to include the internal hidraw header.

Introduce hidraw_instance() to validate that the device was claimed by
hidraw and return its minor node number, or -ENODEV if hidraw is not
connected or hidraw support is disabled. Also use the new helper in
hid_connect().

Assisted-by: LLM
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/hid/hid-core.c |  2 +-
 drivers/hid/hidraw.c   | 15 +++++++++++++++
 include/linux/hidraw.h |  3 +++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index e2944dbdc9e6..85433f64bda1 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2349,7 +2349,7 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
 				((struct hiddev *)hdev->hiddev)->minor);
 	if (hdev->claimed & HID_CLAIMED_HIDRAW)
 		len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
-				((struct hidraw *)hdev->hidraw)->minor);
+				hidraw_instance(hdev));
 
 	type = "Device";
 	for (i = 0; i < hdev->maxcollection; i++) {
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 9129fabed181..949e7546339f 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -665,6 +665,21 @@ void hidraw_disconnect(struct hid_device *hid)
 }
 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 
+/**
+ * hidraw_instance - get hidraw instance minor number for a HID device
+ * @hdev: HID device
+ *
+ * Return: minor number of the hidraw node, or -ENODEV if not connected
+ */
+int hidraw_instance(const struct hid_device *hdev)
+{
+	if ((hdev->claimed & HID_CLAIMED_HIDRAW) && hdev->hidraw)
+		return ((struct hidraw *)hdev->hidraw)->minor;
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(hidraw_instance);
+
 int __init hidraw_init(void)
 {
 	int result;
diff --git a/include/linux/hidraw.h b/include/linux/hidraw.h
index 18fd30a288de..3021454ba513 100644
--- a/include/linux/hidraw.h
+++ b/include/linux/hidraw.h
@@ -5,6 +5,7 @@
 #ifndef _HIDRAW_H
 #define _HIDRAW_H
 
+#include <linux/errno.h>
 #include <uapi/linux/hidraw.h>
 
 
@@ -41,12 +42,14 @@ void hidraw_exit(void);
 int hidraw_report_event(struct hid_device *, u8 *, int);
 int hidraw_connect(struct hid_device *);
 void hidraw_disconnect(struct hid_device *);
+int hidraw_instance(const struct hid_device *hdev);
 #else
 static inline int hidraw_init(void) { return 0; }
 static inline void hidraw_exit(void) { }
 static inline int hidraw_report_event(struct hid_device *hid, u8 *data, int len) { return 0; }
 static inline int hidraw_connect(struct hid_device *hid) { return -1; }
 static inline void hidraw_disconnect(struct hid_device *hid) { }
+static inline int hidraw_instance(const struct hid_device *hdev) { return -ENODEV; }
 #endif
 
 #endif

-- 
2.56.0.176.g3575e65682-goog