2 files changed, 32 insertions, 8 deletions

diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index eb6cc9d..c55469f 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -331,14 +331,18 @@ 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(bus_dma_tag_t dmat, void** vaddr, int flags,
-		 bus_dmamap_t *mapp)
+bus_dmamem_alloc_size(bus_dma_tag_t dmat, void** vaddr, int flags,
+		      bus_dmamap_t *mapp, bus_size_t size)
 {
+
+	if (size > dmat->maxsize)
+		return (ENOMEM);
+
 	/* If we succeed, no mapping/bouncing will be required */
 	*mapp = NULL;
 
-	if ((dmat->maxsize <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem)) {
-		*vaddr = malloc(dmat->maxsize, M_DEVBUF,
+	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem)) {
+		*vaddr = malloc(size, M_DEVBUF,
 				(flags & BUS_DMA_NOWAIT) ? M_NOWAIT : 0);
 	} else {
 		/*
@@ -346,7 +350,7 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 		 *     and handles multi-seg allocations.  Nobody is doing
 		 *     multi-seg allocations yet though.
 		 */
-		*vaddr = contigmalloc(dmat->maxsize, M_DEVBUF,
+		*vaddr = contigmalloc(size, M_DEVBUF,
 		    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : 0,
 		    0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 		    dmat->boundary);
@@ -356,12 +360,20 @@ bus_dmamem_alloc(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(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
+bus_dmamem_free_size(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map,
+		     bus_size_t size)
 {
 	/*
 	 * dmamem does not need to be bounced, so the map should be
@@ -369,10 +381,16 @@ bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 	 */
 	if (map != NULL)
 		panic("bus_dmamem_free: Invalid map freed\n");
-	if ((dmat->maxsize <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem))
+	if ((size <= PAGE_SIZE) && dmat->lowaddr >= ptoa(Maxmem))
 		free(vaddr, M_DEVBUF);
 	else
-		contigfree(vaddr, dmat->maxsize, M_DEVBUF);
+		contigfree(vaddr, size, M_DEVBUF);
+}
+
+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 ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
diff --git a/sys/amd64/include/bus_dma.h b/sys/amd64/include/bus_dma.h
index 6790731..4a1740d 100644
--- a/sys/amd64/include/bus_dma.h
+++ b/sys/amd64/include/bus_dma.h
@@ -180,6 +180,9 @@ 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);
 
@@ -187,6 +190,9 @@ 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);
 
 /*