Fix various NIC drivers to properly cleanup static DMA resources.

In particular, don't check the value of the bus_dma map against NULL
to determine if either bus_dmamem_alloc() or bus_dmamap_load() succeeded.
Instead, assume that bus_dmamap_load() succeeeded (and thus that
bus_dmamap_unload() should be called) if the bus address for a resource
is non-zero, and assume that bus_dmamem_alloc() succeeded (and thus
that bus_dmamem_free() should be called) if the virtual address for a
resource is not NULL.

In many cases these bugs could result in leaks when a driver was detached.

Reviewed by:	yongari
MFC after:	2 weeks

1 files changed, 7 insertions, 8 deletions

diff --git a/sys/arm/at91/if_macb.c b/sys/arm/at91/if_macb.c
index 1a46adc..a60cddf 100644
--- a/sys/arm/at91/if_macb.c
+++ b/sys/arm/at91/if_macb.c
@@ -258,14 +258,14 @@ macb_free_desc_dma_tx(struct macb_softc *sc)
 
 	/* TX descriptor ring. */
 	if (sc->dmatag_data_tx != NULL) {
-		if (sc->dmamap_ring_tx != NULL)
+		if (sc->ring_paddr_tx != 0)
 			bus_dmamap_unload(sc->dmatag_data_tx,
 			    sc->dmamap_ring_tx);
-		if (sc->dmamap_ring_tx != NULL && sc->desc_tx != NULL)
+		if (sc->desc_tx != NULL)
 			bus_dmamem_free(sc->dmatag_data_tx, sc->desc_tx,
 			    sc->dmamap_ring_tx);
-		sc->dmamap_ring_tx = NULL;
-		sc->dmamap_ring_tx = NULL;
+		sc->ring_paddr_tx = 0;
+		sc->desc_tx = NULL;
 		bus_dma_tag_destroy(sc->dmatag_data_tx);
 		sc->dmatag_data_tx = NULL;
 	}
@@ -389,15 +389,14 @@ macb_free_desc_dma_rx(struct macb_softc *sc)
 	}
 	/* RX descriptor ring. */
 	if (sc->dmatag_data_rx != NULL) {
-		if (sc->dmamap_ring_rx != NULL)
+		if (sc->ring_paddr_rx != 0)
 			bus_dmamap_unload(sc->dmatag_data_rx,
 			    sc->dmamap_ring_rx);
-		if (sc->dmamap_ring_rx != NULL &&
-		    sc->desc_rx != NULL)
+		if (sc->desc_rx != NULL)
 			bus_dmamem_free(sc->dmatag_data_rx, sc->desc_rx,
 			    sc->dmamap_ring_rx);
+		sc->ring_paddr_rx = 0;
 		sc->desc_rx = NULL;
-		sc->dmamap_ring_rx = NULL;
 		bus_dma_tag_destroy(sc->dmatag_data_rx);
 		sc->dmatag_data_rx = NULL;
 	}