This routine doesn't seem to be used nowadays.

Index: sys/scsi/scsi_base.c
===================================================================
RCS file: /OpenBSD/src/sys/scsi/scsi_base.c,v
diff -u -p -u -p -r1.285 scsi_base.c
--- sys/scsi/scsi_base.c	22 Apr 2026 12:28:08 -0000	1.285
+++ sys/scsi/scsi_base.c	20 Sep 2026 16:47:44 -0000
@@ -354,31 +354,6 @@ scsi_ioh_add(struct scsi_iohandler *ioh)
 	return rv;
 }
 
-int
-scsi_ioh_del(struct scsi_iohandler *ioh)
-{
-	struct scsi_iopool	*iopl = ioh->pool;
-	int			 rv = 0;
-
-	mtx_enter(&iopl->mtx);
-	switch (ioh->q_state) {
-	case RUNQ_POOLQ:
-		TAILQ_REMOVE(&iopl->queue, ioh, q_entry);
-		ioh->q_state = RUNQ_IDLE;
-		rv = 1;
-		break;
-#ifdef DIAGNOSTIC
-	case RUNQ_IDLE:
-		break;
-	default:
-		panic("scsi_ioh_del: unexpected state %u", ioh->q_state);
-#endif /* DIAGNOSTIC */
-	}
-	mtx_leave(&iopl->mtx);
-
-	return rv;
-}
-
 /*
  * internal iopool runqueue handling.
  */
Index: sys/scsi/scsiconf.h
===================================================================
RCS file: /OpenBSD/src/sys/scsi/scsiconf.h,v
diff -u -p -u -p -r1.202 scsiconf.h
--- sys/scsi/scsiconf.h	10 May 2023 15:28:26 -0000	1.202
+++ sys/scsi/scsiconf.h	20 Sep 2026 16:47:44 -0000
@@ -557,7 +557,6 @@ void	scsi_default_put(void *, void *);
 void	scsi_ioh_set(struct scsi_iohandler *, struct scsi_iopool *,
 	    void (*)(void *, void *), void *);
 int	scsi_ioh_add(struct scsi_iohandler *);
-int	scsi_ioh_del(struct scsi_iohandler *);
 
 void	scsi_xsh_set(struct scsi_xshandler *, struct scsi_link *,
 	    void (*)(struct scsi_xfer *));