diff --git a/sys/alpha/alpha/busdma_machdep.c b/sys/alpha/alpha/busdma_machdep.c
index 90a93895f2b..57c0dd829cf 100644
--- a/sys/alpha/alpha/busdma_machdep.c
+++ b/sys/alpha/alpha/busdma_machdep.c
@@ -350,18 +350,14 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
  * A dmamap to for use with dmamap_load is also allocated.
  */
 int
-bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-		      bus_dmamap_t *mapp, bus_size_t size)
+bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
+		 bus_dmamap_t *mapp)
 {
-
-	if (size > dmat->maxsize)
-		return (ENOMEM);
-
 	/* If we succeed, no mapping/bouncing will be required */
 	*mapp = &nobounce_dmamap;
 
-	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem)) {
-		*vaddr = malloc(size, M_DEVBUF,
+	if ((dmat->maxsize <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem)) {
+		*vaddr = malloc(dmat->maxsize, M_DEVBUF,
 				(flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK);
 	} else {
 		/*
@@ -370,7 +366,7 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 		 *     multi-seg allocations yet though.
 		 */
 		mtx_lock(&Giant);
-		*vaddr = contigmalloc(size, M_DEVBUF,
+		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
 		    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK,
 		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 		    dmat->boundary);
@@ -381,20 +377,12 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 	return (0);
 }
 
-int
-bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
-		 bus_dmamap_t *mapp)
-{
-	return (bus_dmamem_alloc_size(dmat, vaddr, flags, mapp, dmat->maxsize));
-}
-
 /*
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.
  */
 void
-bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-		     bus_size_t size)
+bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 {
 	/*
 	 * dmamem does not need to be bounced, so the map should be
@@ -402,21 +390,15 @@ bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
 	 */
 	if (map != &nobounce_dmamap)
 		panic("bus_dmamem_free: Invalid map freed\n");
-	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem))
+	if ((dmat->maxsize <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem))
 		free(vaddr, M_DEVBUF);
 	else {
 		mtx_lock(&Giant);
-		contigfree(vaddr, size, M_DEVBUF);
+		contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 		mtx_unlock(&Giant);
 	}
 }
 
-void
-bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
-{
-	bus_dmamem_free_size(dmat, vaddr, map, dmat->maxsize);
-}
-
 #define BUS_DMAMAP_NSEGS ((64 * 1024 / PAGE_SIZE) + 1)
 
 /*
diff --git a/sys/alpha/include/bus.h b/sys/alpha/include/bus.h
index 859adc2bd61..852648d7661 100644
--- a/sys/alpha/include/bus.h
+++ b/sys/alpha/include/bus.h
@@ -567,9 +567,6 @@ int bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map);
  * bus device space based on the constraints lited in the dma tag.
  * A dmamap to for use with dmamap_load is also allocated.
  */
-int bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-			  bus_dmamap_t *mapp, bus_size_t size);
-
 int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		     bus_dmamap_t *mapp);
 
@@ -577,9 +574,6 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.
  */
-void bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-			  bus_size_t size);
-
 void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map);
 
 /*
diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index 5080240c8f8..47b8c426aaf 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -338,19 +338,15 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
  * A dmamap to for use with dmamap_load is also allocated.
  */
 int
-bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-		      bus_dmamap_t *mapp, bus_size_t size)
+bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
+		 bus_dmamap_t *mapp)
 {
-
-	if (size > dmat->maxsize)
-		return (ENOMEM);
-
 	/* If we succeed, no mapping/bouncing will be required */
 	*mapp = NULL;
 
-	if ((size <= PAGE_SIZE) &&
+	if ((dmat->maxsize <= PAGE_SIZE) &&
 	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
-		*vaddr = malloc(size, M_DEVBUF,
+		*vaddr = malloc(dmat->maxsize, M_DEVBUF,
 				(flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK);
 	} else {
 		/*
@@ -359,7 +355,7 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 		 *     multi-seg allocations yet though.
 		 */
 		mtx_lock(&Giant);
-		*vaddr = contigmalloc(size, M_DEVBUF,
+		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
 		    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK,
 		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 		    dmat->boundary);
@@ -370,20 +366,12 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 	return (0);
 }
 
-int
-bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
-		 bus_dmamap_t *mapp)
-{
-	return (bus_dmamem_alloc_size(dmat, vaddr, flags, mapp, dmat->maxsize));
-}
-
 /*
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
  */
 void
-bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-		     bus_size_t size)
+bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 {
 	/*
 	 * dmamem does not need to be bounced, so the map should be
@@ -391,21 +379,16 @@ bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
 	 */
 	if (map != NULL)
 		panic("bus_dmamem_free: Invalid map freed\n");
-	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
+	if ((dmat->maxsize <= PAGE_SIZE)
+	 && dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
 		free(vaddr, M_DEVBUF);
 	else {
 		mtx_lock(&Giant);
-		contigfree(vaddr, size, M_DEVBUF);
+		contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 		mtx_unlock(&Giant);
 	}
 }
 
-void
-bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
-{
-	bus_dmamem_free_size(dmat, vaddr, map, dmat->maxsize);
-}
-
 /*
  * Utility function to load a linear buffer.  lastaddrp holds state
  * between invocations (for multiple-buffer loads).  segp contains
diff --git a/sys/amd64/include/bus_dma.h b/sys/amd64/include/bus_dma.h
index 70e498f9e8a..67609d99b0b 100644
--- a/sys/amd64/include/bus_dma.h
+++ b/sys/amd64/include/bus_dma.h
@@ -176,9 +176,6 @@ int bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map);
  * bus device space based on the constraints lited in the dma tag.
  * A dmamap to for use with dmamap_load is also allocated.
  */
-int bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-			  bus_dmamap_t *mapp, bus_size_t size);
-
 int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		     bus_dmamap_t *mapp);
 
@@ -186,9 +183,6 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.
  */
-void bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-			  bus_size_t size);
-
 void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map);
 
 /*
diff --git a/sys/i386/i386/busdma_machdep.c b/sys/i386/i386/busdma_machdep.c
index 5080240c8f8..47b8c426aaf 100644
--- a/sys/i386/i386/busdma_machdep.c
+++ b/sys/i386/i386/busdma_machdep.c
@@ -338,19 +338,15 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
  * A dmamap to for use with dmamap_load is also allocated.
  */
 int
-bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-		      bus_dmamap_t *mapp, bus_size_t size)
+bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
+		 bus_dmamap_t *mapp)
 {
-
-	if (size > dmat->maxsize)
-		return (ENOMEM);
-
 	/* If we succeed, no mapping/bouncing will be required */
 	*mapp = NULL;
 
-	if ((size <= PAGE_SIZE) &&
+	if ((dmat->maxsize <= PAGE_SIZE) &&
 	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem)) {
-		*vaddr = malloc(size, M_DEVBUF,
+		*vaddr = malloc(dmat->maxsize, M_DEVBUF,
 				(flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK);
 	} else {
 		/*
@@ -359,7 +355,7 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 		 *     multi-seg allocations yet though.
 		 */
 		mtx_lock(&Giant);
-		*vaddr = contigmalloc(size, M_DEVBUF,
+		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
 		    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK,
 		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 		    dmat->boundary);
@@ -370,20 +366,12 @@ bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
 	return (0);
 }
 
-int
-bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
-		 bus_dmamap_t *mapp)
-{
-	return (bus_dmamem_alloc_size(dmat, vaddr, flags, mapp, dmat->maxsize));
-}
-
 /*
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
  */
 void
-bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-		     bus_size_t size)
+bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 {
 	/*
 	 * dmamem does not need to be bounced, so the map should be
@@ -391,21 +379,16 @@ bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
 	 */
 	if (map != NULL)
 		panic("bus_dmamem_free: Invalid map freed\n");
-	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
+	if ((dmat->maxsize <= PAGE_SIZE)
+	 && dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem))
 		free(vaddr, M_DEVBUF);
 	else {
 		mtx_lock(&Giant);
-		contigfree(vaddr, size, M_DEVBUF);
+		contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 		mtx_unlock(&Giant);
 	}
 }
 
-void
-bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
-{
-	bus_dmamem_free_size(dmat, vaddr, map, dmat->maxsize);
-}
-
 /*
  * Utility function to load a linear buffer.  lastaddrp holds state
  * between invocations (for multiple-buffer loads).  segp contains
diff --git a/sys/i386/include/bus_dma.h b/sys/i386/include/bus_dma.h
index f9471c03f2c..f706677cccd 100644
--- a/sys/i386/include/bus_dma.h
+++ b/sys/i386/include/bus_dma.h
@@ -176,9 +176,6 @@ int bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map);
  * bus device space based on the constraints lited in the dma tag.
  * A dmamap to for use with dmamap_load is also allocated.
  */
-int bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-			  bus_dmamap_t *mapp, bus_size_t size);
-
 int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		     bus_dmamap_t *mapp);
 
@@ -186,9 +183,6 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.
  */
-void bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-			  bus_size_t size);
-
 void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map);
 
 /*
diff --git a/sys/sparc64/include/bus.h b/sys/sparc64/include/bus.h
index bc6e518bd55..c69c27052c0 100644
--- a/sys/sparc64/include/bus.h
+++ b/sys/sparc64/include/bus.h
@@ -980,12 +980,8 @@ struct bus_dma_tag {
 	/*
 	 * DMA memory utility functions.
 	 */
-	int	(*dt_dmamem_alloc_size)(bus_dma_tag_t, bus_dma_tag_t, void **,
-	    int, bus_dmamap_t *, bus_size_t size);
 	int	(*dt_dmamem_alloc)(bus_dma_tag_t, bus_dma_tag_t, void **, int,
 	    bus_dmamap_t *);
-	void	(*dt_dmamem_free_size)(bus_dma_tag_t, bus_dma_tag_t, void *,
-	    bus_dmamap_t, bus_size_t size);
 	void	(*dt_dmamem_free)(bus_dma_tag_t, bus_dma_tag_t, void *,
 	    bus_dmamap_t);
 };
@@ -1095,19 +1091,6 @@ sparc64_dmamap_sync(bus_dma_tag_t pt, bus_dma_tag_t dt, bus_dmamap_t m, int op)
 #define	bus_dmamap_sync(t, m, op)					\
 	sparc64_dmamap_sync((t), (t), (m), (op))
 
-static __inline int
-sparc64_dmamem_alloc_size(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
-    bus_dmamap_t *m, bus_size_t s)
-{
-	bus_dma_tag_t lt;
-
-	for (lt = pt; lt->dt_dmamem_alloc_size == NULL; lt = lt->dt_parent)
-		;
-	return ((*lt->dt_dmamem_alloc_size)(lt, dt, v, f, m, s));
-}
-#define	bus_dmamem_alloc_size(t, v, f, m, s)				\
-	sparc64_dmamem_alloc_size((t), (t), (v), (f), (m), (s))
-
 static __inline int
 sparc64_dmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
     bus_dmamap_t *m)
@@ -1121,19 +1104,6 @@ sparc64_dmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, void **v, int f,
 #define	bus_dmamem_alloc(t, v, f, m)					\
 	sparc64_dmamem_alloc((t), (t), (v), (f), (m))
 
-static __inline void
-sparc64_dmamem_free_size(bus_dma_tag_t pt, bus_dma_tag_t dt, void *v,
-    bus_dmamap_t m, bus_size_t s)
-{
-	bus_dma_tag_t lt;
-
-	for (lt = pt; lt->dt_dmamem_free_size == NULL; lt = lt->dt_parent)
-		;
-	(*lt->dt_dmamem_free_size)(lt, dt, v, m, s);
-}
-#define	bus_dmamem_free_size(t, v, m, s)				\
-	sparc64_dmamem_free_size((t), (t), (v), (m), (s))
-
 static __inline void
 sparc64_dmamem_free(bus_dma_tag_t pt, bus_dma_tag_t dt, void *v,
     bus_dmamap_t m)
diff --git a/sys/sparc64/include/iommuvar.h b/sys/sparc64/include/iommuvar.h
index 458400130f7..5337d141395 100644
--- a/sys/sparc64/include/iommuvar.h
+++ b/sys/sparc64/include/iommuvar.h
@@ -95,12 +95,8 @@ void iommu_dvmamap_unload(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     bus_dmamap_t);
 void iommu_dvmamap_sync(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     bus_dmamap_t, int);
-int iommu_dvmamem_alloc_size(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
-    void **, int, bus_dmamap_t *, bus_size_t size);
 int iommu_dvmamem_alloc(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     void **, int, bus_dmamap_t *);
-void iommu_dvmamem_free_size(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
-    void *, bus_dmamap_t, bus_size_t size);
 void iommu_dvmamem_free(bus_dma_tag_t, bus_dma_tag_t, struct iommu_state *,
     void *, bus_dmamap_t);
 
diff --git a/sys/sparc64/pci/psycho.c b/sys/sparc64/pci/psycho.c
index 25234d78186..5de26badb4e 100644
--- a/sys/sparc64/pci/psycho.c
+++ b/sys/sparc64/pci/psycho.c
@@ -112,12 +112,8 @@ static int psycho_dmamap_load_uio(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t,
     struct uio *, bus_dmamap_callback2_t *, void *, int);
 static void psycho_dmamap_unload(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t);
 static void psycho_dmamap_sync(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t, int);
-static int psycho_dmamem_alloc_size(bus_dma_tag_t, bus_dma_tag_t, void **, int,
-    bus_dmamap_t *, bus_size_t size);
 static int psycho_dmamem_alloc(bus_dma_tag_t, bus_dma_tag_t, void **, int,
     bus_dmamap_t *);
-static void psycho_dmamem_free_size(bus_dma_tag_t, bus_dma_tag_t, void *,
-    bus_dmamap_t, bus_size_t size);
 static void psycho_dmamem_free(bus_dma_tag_t, bus_dma_tag_t, void *,
     bus_dmamap_t);
 
@@ -501,9 +497,7 @@ psycho_attach(device_t dev)
 	sc->sc_dmat->dt_dmamap_load_uio = psycho_dmamap_load_uio;
 	sc->sc_dmat->dt_dmamap_unload = psycho_dmamap_unload;
 	sc->sc_dmat->dt_dmamap_sync = psycho_dmamap_sync;
-	sc->sc_dmat->dt_dmamem_alloc_size = psycho_dmamem_alloc_size;
 	sc->sc_dmat->dt_dmamem_alloc = psycho_dmamem_alloc;
-	sc->sc_dmat->dt_dmamem_free_size = psycho_dmamem_free_size;
 	sc->sc_dmat->dt_dmamem_free = psycho_dmamem_free;
 	/* XXX: register as root dma tag (kluge). */
 	sparc64_root_dma_tag = sc->sc_dmat;
@@ -1319,17 +1313,6 @@ psycho_alloc_bus_tag(struct psycho_softc *sc, int type)
 /*
  * hooks into the iommu dvma calls.
  */
-static int
-psycho_dmamem_alloc_size(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
-    int flags, bus_dmamap_t *mapp, bus_size_t size)
-{
-	struct psycho_softc *sc;
-
-	sc = (struct psycho_softc *)pdmat->dt_cookie;
-	return (iommu_dvmamem_alloc_size(pdmat, ddmat, sc->sc_is, vaddr, flags,
-	    mapp, size));
-}
-
 static int
 psycho_dmamem_alloc(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
     int flags, bus_dmamap_t *mapp)
@@ -1341,16 +1324,6 @@ psycho_dmamem_alloc(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
 	    mapp));
 }
 
-static void
-psycho_dmamem_free_size(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void *vaddr,
-    bus_dmamap_t map, bus_size_t size)
-{
-	struct psycho_softc *sc;
-
-	sc = (struct psycho_softc *)pdmat->dt_cookie;
-	iommu_dvmamem_free_size(pdmat, ddmat, sc->sc_is, vaddr, map, size);
-}
-
 static void
 psycho_dmamem_free(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void *vaddr,
     bus_dmamap_t map)
diff --git a/sys/sparc64/sbus/sbus.c b/sys/sparc64/sbus/sbus.c
index f695d5acc0c..8debb26fe31 100644
--- a/sys/sparc64/sbus/sbus.c
+++ b/sys/sparc64/sbus/sbus.c
@@ -243,12 +243,8 @@ static int sbus_dmamap_load_uio(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t,
     struct uio *, bus_dmamap_callback2_t *, void *, int);
 static void sbus_dmamap_unload(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t);
 static void sbus_dmamap_sync(bus_dma_tag_t, bus_dma_tag_t, bus_dmamap_t, int);
-static int sbus_dmamem_alloc_size(bus_dma_tag_t, bus_dma_tag_t, void **, int,
-    bus_dmamap_t *, bus_size_t size);
 static int sbus_dmamem_alloc(bus_dma_tag_t, bus_dma_tag_t, void **, int,
     bus_dmamap_t *);
-static void sbus_dmamem_free_size(bus_dma_tag_t, bus_dma_tag_t, void *,
-    bus_dmamap_t, bus_size_t);
 static void sbus_dmamem_free(bus_dma_tag_t, bus_dma_tag_t, void *,
     bus_dmamap_t);
 
@@ -352,9 +348,7 @@ sbus_probe(device_t dev)
 	sc->sc_cdmatag->dt_dmamap_load_uio = sbus_dmamap_load_uio;
 	sc->sc_cdmatag->dt_dmamap_unload = sbus_dmamap_unload;
 	sc->sc_cdmatag->dt_dmamap_sync = sbus_dmamap_sync;
-	sc->sc_cdmatag->dt_dmamem_alloc_size = sbus_dmamem_alloc_size;
 	sc->sc_cdmatag->dt_dmamem_alloc = sbus_dmamem_alloc;
-	sc->sc_cdmatag->dt_dmamem_free_size = sbus_dmamem_free_size;
 	sc->sc_cdmatag->dt_dmamem_free = sbus_dmamem_free;
 	/* XXX: register as root dma tag (kluge). */
 	sparc64_root_dma_tag = sc->sc_cdmatag;
@@ -992,16 +986,6 @@ sbus_dmamap_sync(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, bus_dmamap_t map,
 	iommu_dvmamap_sync(pdmat, ddmat, &sc->sc_is, map, op);
 }
 
-static int
-sbus_dmamem_alloc_size(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
-    int flags, bus_dmamap_t *mapp, bus_size_t size)
-{
-	struct sbus_softc *sc = (struct sbus_softc *)pdmat->dt_cookie;
-
-	return (iommu_dvmamem_alloc_size(pdmat, ddmat, &sc->sc_is, vaddr, flags,
-		    mapp, size));
-}
-
 static int
 sbus_dmamem_alloc(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
     int flags, bus_dmamap_t *mapp)
@@ -1012,15 +996,6 @@ sbus_dmamem_alloc(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void **vaddr,
 		    mapp));
 }
 
-static void
-sbus_dmamem_free_size(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void *vaddr,
-    bus_dmamap_t map, bus_size_t size)
-{
-	struct sbus_softc *sc = (struct sbus_softc *)pdmat->dt_cookie;
-
-	iommu_dvmamem_free_size(pdmat, ddmat, &sc->sc_is, vaddr, map, size);
-}
-
 static void
 sbus_dmamem_free(bus_dma_tag_t pdmat, bus_dma_tag_t ddmat, void *vaddr,
     bus_dmamap_t map)
diff --git a/sys/sparc64/sparc64/iommu.c b/sys/sparc64/sparc64/iommu.c
index ccfe1aff354..c42e25d5fce 100644
--- a/sys/sparc64/sparc64/iommu.c
+++ b/sys/sparc64/sparc64/iommu.c
@@ -668,22 +668,18 @@ iommu_dvma_vallocseg(bus_dma_tag_t dt, struct iommu_state *is, bus_dmamap_t map,
 }
 
 int
-iommu_dvmamem_alloc_size(bus_dma_tag_t pt, bus_dma_tag_t dt,
-    struct iommu_state *is, void **vaddr, int flags, bus_dmamap_t *mapp,
-    bus_size_t size)
+iommu_dvmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, struct iommu_state *is,
+    void **vaddr, int flags, bus_dmamap_t *mappe)
 {
 	int error;
 
-	if (size > dt->dt_maxsize)
-		return (ENOMEM);
-
 	/*
 	 * XXX: This will break for 32 bit transfers on machines with more than
 	 * 16G (1 << 34 bytes) of memory.
 	 */
 	if ((error = sparc64_dmamem_alloc_map(dt, mapp)) != 0)
 		return (error);
-	if ((*vaddr = malloc(size, M_IOMMU,
+	if ((*vaddr = malloc(dt->dt_maxsize, M_IOMMU,
 	    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK)) == NULL) {
 		error = ENOMEM;
 		sparc64_dmamem_free_map(dt, *mapp);
@@ -694,33 +690,18 @@ iommu_dvmamem_alloc_size(bus_dma_tag_t pt, bus_dma_tag_t dt,
 	 * Try to preallocate DVMA space. If this fails, it is retried at load
 	 * time.
 	 */
-	iommu_dvma_valloc(dt, is, *mapp, IOMMU_SIZE_ROUNDUP(size));
+	iommu_dvma_valloc(dt, is, *mapp, IOMMU_SIZE_ROUNDUP(dt->dt_maxsize));
 	return (0);
 }
 
-int
-iommu_dvmamem_alloc(bus_dma_tag_t pt, bus_dma_tag_t dt, struct iommu_state *is,
-    void **vaddr, int flags, bus_dmamap_t *mapp)
-{
-	return (iommu_dvmamem_alloc_size(pt, dt, is, vaddr, flags, mapp,
-	    dt->dt_maxsize));
-}
-
-void
-iommu_dvmamem_free_size(bus_dma_tag_t pt, bus_dma_tag_t dt,
-    struct iommu_state *is, void *vaddr, bus_dmamap_t map, bus_size_t size)
-{
-
-	iommu_dvma_vfree(is, map);
-	sparc64_dmamem_free_map(dt, map);
-	free(vaddr, M_IOMMU);
-}
-
 void
 iommu_dvmamem_free(bus_dma_tag_t pt, bus_dma_tag_t dt, struct iommu_state *is,
     void *vaddr, bus_dmamap_t map)
 {
-	iommu_dvmamem_free_size(pt, dt, is, vaddr, map, dt->dt_maxsize);
+
+	iommu_dvma_vfree(is, map);
+	sparc64_dmamem_free_map(dt, map);
+	free(vaddr, M_IOMMU);
 }
 
 int
diff --git a/sys/sys/bus_dma.h b/sys/sys/bus_dma.h
index f9471c03f2c..f706677cccd 100644
--- a/sys/sys/bus_dma.h
+++ b/sys/sys/bus_dma.h
@@ -176,9 +176,6 @@ int bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map);
  * bus device space based on the constraints lited in the dma tag.
  * A dmamap to for use with dmamap_load is also allocated.
  */
-int bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
-			  bus_dmamap_t *mapp, bus_size_t size);
-
 int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		     bus_dmamap_t *mapp);
 
@@ -186,9 +183,6 @@ int bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
  * Free a piece of memory and it's allociated dmamap, that was allocated
  * via bus_dmamem_alloc.
  */
-void bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
-			  bus_size_t size);
-
 void bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map);
 
 /*