net: rose: split remove and free operations in rose_remove_neigh()

The current rose_remove_neigh() performs two distinct operations:
1. Removes rose_neigh from rose_neigh_list
2. Frees the rose_neigh structure

Split these operations into separate functions to improve maintainability
and prepare for upcoming refcount_t conversion. The timer cleanup remains
in rose_remove_neigh() because free operations can be called from timer
itself.

This patch introduce rose_neigh_put() to handle the freeing of rose_neigh
structures and modify rose_remove_neigh() to handle removal only.

Signed-off-by: Takamitsu Iwai <takamitz@amazon.co.jp>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250823085857.47674-2-takamitz@amazon.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Takamitsu Iwai

include/net/rose.h

@@ -151,6 +151,14 @@ struct rose_sock {
 
 #define rose_sk(sk) ((struct rose_sock *)(sk))
 
+static inline void rose_neigh_put(struct rose_neigh *rose_neigh)
+{
+	if (rose_neigh->ax25)
+		ax25_cb_put(rose_neigh->ax25);
+	kfree(rose_neigh->digipeat);
+	kfree(rose_neigh);
+}
+
 /* af_rose.c */
 extern ax25_address rose_callsign;
 extern int  sysctl_rose_restart_request_timeout;

net/rose/rose_route.c

@@ -234,20 +234,12 @@ static void rose_remove_neigh(struct rose_neigh *rose_neigh)
 
 	if ((s = rose_neigh_list) == rose_neigh) {
 		rose_neigh_list = rose_neigh->next;
-		if (rose_neigh->ax25)
-			ax25_cb_put(rose_neigh->ax25);
-		kfree(rose_neigh->digipeat);
-		kfree(rose_neigh);
 		return;
 	}
 
 	while (s != NULL && s->next != NULL) {
 		if (s->next == rose_neigh) {
 			s->next = rose_neigh->next;
-			if (rose_neigh->ax25)
-				ax25_cb_put(rose_neigh->ax25);
-			kfree(rose_neigh->digipeat);
-			kfree(rose_neigh);
 			return;
 		}
 
@@ -331,8 +323,10 @@ static int rose_del_node(struct rose_route_struct *rose_route,
 		if (rose_node->neighbour[i] == rose_neigh) {
 			rose_neigh->count--;
 
-			if (rose_neigh->count == 0 && rose_neigh->use == 0)
+			if (rose_neigh->count == 0 && rose_neigh->use == 0) {
 				rose_remove_neigh(rose_neigh);
+				rose_neigh_put(rose_neigh);
+			}
 
 			rose_node->count--;
 
@@ -513,6 +507,7 @@ void rose_rt_device_down(struct net_device *dev)
 		}
 
 		rose_remove_neigh(s);
+		rose_neigh_put(s);
 	}
 	spin_unlock_bh(&rose_neigh_list_lock);
 	spin_unlock_bh(&rose_node_list_lock);
@@ -569,6 +564,7 @@ static int rose_clear_routes(void)
 		if (s->use == 0 && !s->loopback) {
 			s->count = 0;
 			rose_remove_neigh(s);
+			rose_neigh_put(s);
 		}
 	}
 
@@ -1301,6 +1297,7 @@ void __exit rose_rt_free(void)
 		rose_neigh = rose_neigh->next;
 
 		rose_remove_neigh(s);
+		rose_neigh_put(s);
 	}
 
 	while (rose_node != NULL) {