diff mbox series

[v6,4/5] usb: gadget: add trace event of configfs link/unlink operation

Message ID 1649294865-4388-5-git-send-email-quic_linyyuan@quicinc.com
State New
Headers show
Series usb: gadget: configfs: new trace events | expand

Commit Message

Linyu Yuan April 7, 2022, 1:27 a.m. UTC 
Add API trace_usb_configfs_link/unlink_group() to trace user space
link/unlink a group like add function to configuration or
remove function from configuration.
If a specific function need link/unlink, it also can be used.

Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
---
v2: no change
v3: add API in trace.c
v4: fix memory leak
v5: no change
v6: fix checkpatch warning

 drivers/usb/gadget/configfs.c              |  8 ++++++
 drivers/usb/gadget/function/uvc_configfs.c | 12 ++++++++
 drivers/usb/gadget/trace.c                 | 46 ++++++++++++++++++++++++++++++
 include/linux/usb/composite.h              |  6 ++++
 4 files changed, 72 insertions(+)

Comments

Greg KH April 22, 2022, 8:40 a.m. UTC | #1 
On Thu, Apr 07, 2022 at 09:27:44AM +0800, Linyu Yuan wrote:
> Add API trace_usb_configfs_link/unlink_group() to trace user space
> link/unlink a group like add function to configuration or
> remove function from configuration.
> If a specific function need link/unlink, it also can be used.

Doesn't configfs have generic trace functions like this?  What is this
going to show you?  Userspace is the thing causing these events to
happen, why do you need trace events for any of these configfs things?

Who is going to use this, and what are they all going to be used for?

thanks,

greg k-h
diff mbox series

Patch

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index a0599fb..a304d29 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -422,6 +422,8 @@  static int config_usb_cfg_link(
 	struct usb_function *f;
 	int ret;
 
+	trace_usb_configfs_link_group(usb_cfg_ci, usb_func_ci);
+
 	mutex_lock(&gi->lock);
 	/*
 	 * Make sure this function is from within our _this_ gadget and not
@@ -471,6 +473,8 @@  static void config_usb_cfg_unlink(
 			to_usb_function_instance(usb_func_ci);
 	struct usb_function *f;
 
+	trace_usb_configfs_unlink_group(usb_cfg_ci, usb_func_ci);
+
 	/*
 	 * ideally I would like to forbid to unlink functions while a gadget is
 	 * bound to an UDC. Since this isn't possible at the moment, we simply
@@ -893,6 +897,8 @@  static int os_desc_link(struct config_item *os_desc_ci,
 	struct usb_configuration *c = NULL, *iter;
 	int ret;
 
+	trace_usb_configfs_link_group(os_desc_ci, usb_cfg_ci);
+
 	mutex_lock(&gi->lock);
 	list_for_each_entry(iter, &cdev->configs, list) {
 		if (iter != &c_target->c)
@@ -924,6 +930,8 @@  static void os_desc_unlink(struct config_item *os_desc_ci,
 	struct gadget_info *gi = os_desc_item_to_gadget_info(os_desc_ci);
 	struct usb_composite_dev *cdev = &gi->cdev;
 
+	trace_usb_configfs_unlink_group(os_desc_ci, usb_cfg_ci);
+
 	mutex_lock(&gi->lock);
 	if (gi->composite.gadget_driver.udc_name)
 		unregister_gadget(gi);
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index cc0f2eb..fc139f3 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -598,6 +598,8 @@  static int uvcg_control_class_allow_link(struct config_item *src,
 	struct uvcg_control_header *target_hdr;
 	int ret = -EINVAL;
 
+	trace_usb_configfs_link_group(src, target);
+
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
 	control = src->ci_parent->ci_parent;
@@ -639,6 +641,8 @@  static void uvcg_control_class_drop_link(struct config_item *src,
 	struct uvc_descriptor_header **class_array;
 	struct uvcg_control_header *target_hdr;
 
+	trace_usb_configfs_unlink_group(src, target);
+
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
 	control = src->ci_parent->ci_parent;
@@ -883,6 +887,8 @@  static int uvcg_streaming_header_allow_link(struct config_item *src,
 	struct uvcg_format_ptr *format_ptr;
 	int i, ret = -EINVAL;
 
+	trace_usb_configfs_link_group(src, target);
+
 	src_hdr = to_uvcg_streaming_header(src);
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
@@ -946,6 +952,8 @@  static void uvcg_streaming_header_drop_link(struct config_item *src,
 	struct uvcg_format *target_fmt = NULL;
 	struct uvcg_format_ptr *format_ptr, *tmp;
 
+	trace_usb_configfs_unlink_group(src, target);
+
 	src_hdr = to_uvcg_streaming_header(src);
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
@@ -2171,6 +2179,8 @@  static int uvcg_streaming_class_allow_link(struct config_item *src,
 	size_t size = 0, count = 0;
 	int ret = -EINVAL;
 
+	trace_usb_configfs_link_group(src, target);
+
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
 	streaming = src->ci_parent->ci_parent;
@@ -2242,6 +2252,8 @@  static void uvcg_streaming_class_drop_link(struct config_item *src,
 	struct uvc_descriptor_header ***class_array;
 	struct uvcg_streaming_header *target_hdr;
 
+	trace_usb_configfs_unlink_group(src, target);
+
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
 
 	streaming = src->ci_parent->ci_parent;
diff --git a/drivers/usb/gadget/trace.c b/drivers/usb/gadget/trace.c
index 65b328f..9b33b30 100644
--- a/drivers/usb/gadget/trace.c
+++ b/drivers/usb/gadget/trace.c
@@ -88,4 +88,50 @@  void trace_usb_configfs_drop_group(struct config_item *parent,
 	trace_usb_configfs_make_drop_group(parent, item, "rmdir");
 }
 EXPORT_SYMBOL(trace_usb_configfs_drop_group);
+
+static void trace_usb_configfs_link_unlink_group(struct config_item *dest,
+		struct config_item *src, char *link_unlink)
+{
+	char *group, *dest_group, *src_group;
+	int ret;
+
+	group = kzalloc(4 * GROUP_LEN, GFP_KERNEL);
+	if (!group)
+		return;
+
+	dest_group = group + 2 * GROUP_LEN;
+	ret = gadget_configfs_group(dest_group, dest);
+	if (ret) {
+		kfree(group);
+		return;
+	}
+
+	src_group = group + 3 * GROUP_LEN;
+	ret = gadget_configfs_group(src_group, src);
+	if (ret) {
+		kfree(group);
+		return;
+	}
+
+	snprintf(group, 2 * GROUP_LEN, "%s %s %s",
+			link_unlink, dest_group, src_group);
+
+	trace_gadget_configfs(group);
+
+	kfree(group);
+}
+
+void trace_usb_configfs_link_group(struct config_item *dest,
+		struct config_item *src)
+{
+	trace_usb_configfs_link_unlink_group(dest, src, "link");
+}
+EXPORT_SYMBOL(trace_usb_configfs_link_group);
+
+void trace_usb_configfs_unlink_group(struct config_item *dest,
+		struct config_item *src)
+{
+	trace_usb_configfs_link_unlink_group(dest, src, "unlink");
+}
+EXPORT_SYMBOL(trace_usb_configfs_unlink_group);
 #endif
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 7bf6574..65dc26e 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -608,9 +608,15 @@  void trace_usb_configfs_make_group(struct config_item *parent,
 		struct config_item *item);
 void trace_usb_configfs_drop_group(struct config_item *parent,
 		struct config_item *item);
+void trace_usb_configfs_link_group(struct config_item *dest,
+		struct config_item *src);
+void trace_usb_configfs_unlink_group(struct config_item *dest,
+		struct config_item *src);
 #else
 #define trace_usb_configfs_make_group(parent, item) do {} while (0)
 #define trace_usb_configfs_drop_group(parent, item) do {} while (0)
+#define trace_usb_configfs_link_group(dest, src) do {} while (0)
+#define trace_usb_configfs_unlink_group(dest, src) do {} while (0)
 #endif
 
 struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev,