usbmon: Use list_for_each_entry() helper

Convert list_for_each() to list_for_each_entry() so that the p/pos
list_head pointer and list_entry() call are no longer needed, which
can reduce a few lines of code. No functional changed.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230830085658.527752-1-ruanjinjie@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mon/mon_main.c

@@ -81,15 +81,12 @@ void mon_reader_del(struct mon_bus *mbus, struct mon_reader *r)
 static void mon_bus_submit(struct mon_bus *mbus, struct urb *urb)
 {
 	unsigned long flags;
-	struct list_head *pos;
 	struct mon_reader *r;
 
 	spin_lock_irqsave(&mbus->lock, flags);
 	mbus->cnt_events++;
-	list_for_each (pos, &mbus->r_list) {
-		r = list_entry(pos, struct mon_reader, r_link);
+	list_for_each_entry(r, &mbus->r_list, r_link)
 		r->rnf_submit(r->r_data, urb);
-	}
 	spin_unlock_irqrestore(&mbus->lock, flags);
 }
 
@@ -108,15 +105,12 @@ static void mon_submit(struct usb_bus *ubus, struct urb *urb)
 static void mon_bus_submit_error(struct mon_bus *mbus, struct urb *urb, int error)
 {
 	unsigned long flags;
-	struct list_head *pos;
 	struct mon_reader *r;
 
 	spin_lock_irqsave(&mbus->lock, flags);
 	mbus->cnt_events++;
-	list_for_each (pos, &mbus->r_list) {
-		r = list_entry(pos, struct mon_reader, r_link);
+	list_for_each_entry(r, &mbus->r_list, r_link)
 		r->rnf_error(r->r_data, urb, error);
-	}
 	spin_unlock_irqrestore(&mbus->lock, flags);
 }
 
@@ -135,15 +129,12 @@ static void mon_submit_error(struct usb_bus *ubus, struct urb *urb, int error)
 static void mon_bus_complete(struct mon_bus *mbus, struct urb *urb, int status)
 {
 	unsigned long flags;
-	struct list_head *pos;
 	struct mon_reader *r;
 
 	spin_lock_irqsave(&mbus->lock, flags);
 	mbus->cnt_events++;
-	list_for_each (pos, &mbus->r_list) {
-		r = list_entry(pos, struct mon_reader, r_link);
+	list_for_each_entry(r, &mbus->r_list, r_link)
 		r->rnf_complete(r->r_data, urb, status);
-	}
 	spin_unlock_irqrestore(&mbus->lock, flags);
 }
 
@@ -165,11 +156,9 @@ static void mon_complete(struct usb_bus *ubus, struct urb *urb, int status)
 static void mon_stop(struct mon_bus *mbus)
 {
 	struct usb_bus *ubus;
-	struct list_head *p;
 
 	if (mbus == &mon_bus0) {
-		list_for_each (p, &mon_buses) {
-			mbus = list_entry(p, struct mon_bus, bus_link);
+		list_for_each_entry(mbus, &mon_buses, bus_link) {
 			/*
 			 * We do not change nreaders here, so rely on mon_lock.
 			 */
@@ -332,14 +321,12 @@ static void mon_bus0_init(void)
  */
 struct mon_bus *mon_bus_lookup(unsigned int num)
 {
-	struct list_head *p;
 	struct mon_bus *mbus;
 
 	if (num == 0) {
 		return &mon_bus0;
 	}
-	list_for_each (p, &mon_buses) {
-		mbus = list_entry(p, struct mon_bus, bus_link);
+	list_for_each_entry(mbus, &mon_buses, bus_link) {
 		if (mbus->u_bus->busnum == num) {
 			return mbus;
 		}