They are redundant because always checked together. These flags are
not used outside unix(4) PCB layer, so the change is local.

Index: sys/kern/uipc_usrreq.c
===================================================================
RCS file: /cvs/src/sys/kern/uipc_usrreq.c,v
retrieving revision 1.201
diff -u -p -r1.201 uipc_usrreq.c
--- sys/kern/uipc_usrreq.c	17 Mar 2024 19:47:08 -0000	1.201
+++ sys/kern/uipc_usrreq.c	19 Mar 2024 10:37:21 -0000
@@ -329,14 +329,14 @@ uipc_bind(struct socket *so, struct mbuf
 	struct nameidata nd;
 	size_t pathlen;
 
-	if (unp->unp_flags & (UNP_BINDING | UNP_CONNECTING))
+	if (unp->unp_flags & UNP_BUSY)
 		return (EINVAL);
 	if (unp->unp_vnode != NULL)
 		return (EINVAL);
 	if ((error = unp_nam2sun(nam, &soun, &pathlen)))
 		return (error);
 
-	unp->unp_flags |= UNP_BINDING;
+	unp->unp_flags |= UNP_BUSY;
 
 	/*
 	 * Enforce `i_lock' -> `solock' because fifo subsystem
@@ -405,7 +405,7 @@ uipc_bind(struct socket *so, struct mbuf
 	VOP_UNLOCK(vp);
 out:
 	KERNEL_UNLOCK();
-	unp->unp_flags &= ~UNP_BINDING;
+	unp->unp_flags &= ~UNP_BUSY;
 
 	return (error);
 }
@@ -415,7 +415,7 @@ uipc_listen(struct socket *so)
 {
 	struct unpcb *unp = sotounpcb(so);
 
-	if (unp->unp_flags & (UNP_BINDING | UNP_CONNECTING))
+	if (unp->unp_flags & UNP_BUSY)
 		return (EINVAL);
 	if (unp->unp_vnode == NULL)
 		return (EINVAL);
@@ -820,7 +820,7 @@ unp_connect(struct socket *so, struct mb
 	int error;
 
 	unp = sotounpcb(so);
-	if (unp->unp_flags & (UNP_BINDING | UNP_CONNECTING))
+	if (unp->unp_flags & UNP_BUSY)
 		return (EISCONN);
 	if ((error = unp_nam2sun(nam, &soun, NULL)))
 		return (error);
@@ -829,7 +829,7 @@ unp_connect(struct socket *so, struct mb
 	nd.ni_pledge = PLEDGE_UNIX;
 	nd.ni_unveil = UNVEIL_WRITE;
 
-	unp->unp_flags |= UNP_CONNECTING;
+	unp->unp_flags |= UNP_BUSY;
 
 	/*
 	 * Enforce `i_lock' -> `solock' because fifo subsystem
@@ -921,7 +921,7 @@ put:
 unlock:
 	KERNEL_UNLOCK();
 	solock(so);
-	unp->unp_flags &= ~UNP_CONNECTING;
+	unp->unp_flags &= ~UNP_BUSY;
 
 	/*
 	 * The peer socket could be closed by concurrent thread
Index: sys/sys/unpcb.h
===================================================================
RCS file: /cvs/src/sys/sys/unpcb.h,v
retrieving revision 1.45
diff -u -p -r1.45 unpcb.h
--- sys/sys/unpcb.h	26 Nov 2022 17:51:18 -0000	1.45
+++ sys/sys/unpcb.h	19 Mar 2024 10:37:21 -0000
@@ -91,8 +91,7 @@ struct	unpcb {
  */
 #define UNP_FEIDS	0x01		/* unp_connid contains information */
 #define UNP_FEIDSBIND	0x02		/* unp_connid was set by a bind */
-#define UNP_BINDING	0x04		/* unp is binding now */
-#define UNP_CONNECTING	0x08		/* unp is connecting now */
+#define UNP_BUSY	0x04		/* unp is binding or connecting now */
 
 /*
  * flag bits in unp_gcflags