Index: sys/arm64/arm64/busdma_bounce.c
===================================================================
--- sys/arm64/arm64/busdma_bounce.c
+++ sys/arm64/arm64/busdma_bounce.c
@@ -74,7 +74,6 @@
 	struct bus_dma_tag_common common;
 	int			map_count;
 	int			bounce_flags;
-	bus_dma_segment_t	*segments;
 	struct bounce_zone	*bounce_zone;
 };
 
@@ -129,6 +128,7 @@
 	int		       pagesneeded;
 	int		       pagesreserved;
 	bus_dma_tag_t	       dmat;
+	bus_dma_segment_t      *segments;
 	struct memdesc	       mem;
 	bus_dmamap_callback_t *callback;
 	void		      *callback_arg;
@@ -184,7 +184,6 @@
 
 	newtag->common.impl = &bus_dma_bounce_impl;
 	newtag->map_count = 0;
-	newtag->segments = NULL;
 
 	if ((flags & BUS_DMA_COHERENT) != 0)
 		newtag->bounce_flags |= BF_COHERENT;
@@ -255,8 +254,6 @@
 			parent = (bus_dma_tag_t)dmat->common.parent;
 			atomic_subtract_int(&dmat->common.ref_count, 1);
 			if (dmat->common.ref_count == 0) {
-				if (dmat->segments != NULL)
-					free(dmat->segments, M_DEVBUF);
 				free(dmat, M_DEVBUF);
 				/*
 				 * Last reference count, so
@@ -312,17 +309,6 @@
 
 	error = 0;
 
-	if (dmat->segments == NULL) {
-		dmat->segments = (bus_dma_segment_t *)malloc(
-		    sizeof(bus_dma_segment_t) * dmat->common.nsegments,
-		    M_DEVBUF, M_NOWAIT);
-		if (dmat->segments == NULL) {
-			CTR3(KTR_BUSDMA, "%s: tag %p error %d",
-			    __func__, dmat, ENOMEM);
-			return (ENOMEM);
-		}
-	}
-
 	*mapp = alloc_dmamap(dmat, M_NOWAIT);
 	if (*mapp == NULL) {
 		CTR3(KTR_BUSDMA, "%s: tag %p error %d",
@@ -330,6 +316,16 @@
 		return (ENOMEM);
 	}
 
+	(*mapp)->segments = (bus_dma_segment_t *)malloc(
+	    sizeof(bus_dma_segment_t) * dmat->common.nsegments,
+	    M_DEVBUF, M_NOWAIT);
+	if ((*mapp)->segments == NULL) {
+		free(*mapp, M_DEVBUF);
+		CTR3(KTR_BUSDMA, "%s: map %p error %d",
+		    __func__, *map, ENOMEM);
+		return (ENOMEM);
+	}
+
 	/*
 	 * Bouncing might be required if the driver asks for an active
 	 * exclusion region, a data alignment that is stricter than 1, and/or
@@ -404,6 +400,7 @@
 		    ("%s: Bounce zone when cannot bounce", __func__));
 		dmat->bounce_zone->map_count--;
 	}
+	free(map->segments, M_DEVBUF);
 	free(map, M_DEVBUF);
 	dmat->map_count--;
 	CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
@@ -435,16 +432,6 @@
 	else
 		mflags = M_WAITOK;
 
-	if (dmat->segments == NULL) {
-		dmat->segments = (bus_dma_segment_t *)malloc(
-		    sizeof(bus_dma_segment_t) * dmat->common.nsegments,
-		    M_DEVBUF, mflags);
-		if (dmat->segments == NULL) {
-			CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
-			    __func__, dmat, dmat->common.flags, ENOMEM);
-			return (ENOMEM);
-		}
-	}
 	if (flags & BUS_DMA_ZERO)
 		mflags |= M_ZERO;
 	if (flags & BUS_DMA_NOCACHE)
@@ -471,6 +458,16 @@
 	}
 	(*mapp)->flags = DMAMAP_FROM_DMAMEM;
 
+	(*mapp)->segments = (bus_dma_segment_t *)malloc(
+	    sizeof(bus_dma_segment_t) * dmat->common.nsegments,
+	    M_DEVBUF, M_NOWAIT);
+	if ((*mapp)->segments == NULL) {
+		free(*mapp, M_DEVBUF);
+		CTR3(KTR_BUSDMA, "%s: map %p error %d",
+		    __func__, *map, ENOMEM);
+		return (ENOMEM);
+	}
+
 	/*
 	 * Allocate the buffer from the malloc(9) allocator if...
 	 *  - It's small enough to fit into a single power of two sized bucket.
@@ -718,7 +715,7 @@
 	int error;
 
 	if (segs == NULL)
-		segs = dmat->segments;
+		segs = map->segments;
 
 	if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 		_bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
@@ -789,7 +786,7 @@
 	int error;
 
 	if (segs == NULL)
-		segs = dmat->segments;
+		segs = map->segments;
 
 	if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 		_bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
@@ -894,7 +891,7 @@
 {
 
 	if (segs == NULL)
-		segs = dmat->segments;
+		segs = map->segments;
 	return (segs);
 }