Introduce bus_dmamap_load_mbuf_sg(). Instead of taking a callback arg, this

cuts to the chase and fills in a provided s/g list.  This is meant to optimize
out the cost of the callback since the callback doesn't serve much purpose for
mbufs since mbuf loads will never be deferred.  This is just for amd64 and
i386 at the moment, other arches will be coming shortly.

1 files changed, 5 insertions, 0 deletions

diff --git a/sys/amd64/include/bus_dma.h b/sys/amd64/include/bus_dma.h
index 7b94b88..fe02855 100644
--- a/sys/amd64/include/bus_dma.h
+++ b/sys/amd64/include/bus_dma.h
@@ -230,6 +230,11 @@ int bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 			 struct mbuf *mbuf,
 			 bus_dmamap_callback2_t *callback, void *callback_arg,
 			 int flags);
+
+int bus_dmamap_load_mbuf_sg(bus_dma_tag_t dmat, bus_dmamap_t map,
+			    struct mbuf *mbuf, bus_dma_segment_t *segs,
+			    int *nsegs, int flags);
+
 /*
  * Like bus_dmamap_load but for uios.  Note the use of the
  * bus_dmamap_callback2_t interface.