Mega busdma API commit.

Add two new arguments to bus_dma_tag_create(): lockfunc and lockfuncarg.
Lockfunc allows a driver to provide a function for managing its locking
semantics while using busdma.  At the moment, this is used for the
asynchronous busdma_swi and callback mechanism.  Two lockfunc implementations
are provided: busdma_lock_mutex() performs standard mutex operations on the
mutex that is specified from lockfuncarg.  dftl_lock() is a panic
implementation and is defaulted to when NULL, NULL are passed to
bus_dma_tag_create().  The only time that NULL, NULL should ever be used is
when the driver ensures that bus_dmamap_load() will not be deferred.
Drivers that do not provide their own locking can pass
busdma_lock_mutex,&Giant args in order to preserve the former behaviour.

sparc64 and powerpc do not provide real busdma_swi functions, so this is
largely a noop on those platforms.  The busdma_swi on is64 is not properly
locked yet, so warnings will be emitted on this platform when busdma
callback deferrals happen.

If anyone gets panics or warnings from dflt_lock() being called, please
let me know right away.

Reviewed by:	tmm, gibbs

1 files changed, 6 insertions, 3 deletions

diff --git a/sys/pci/if_xl.c b/sys/pci/if_xl.c
index b4a43fc..060c859 100644
--- a/sys/pci/if_xl.c
+++ b/sys/pci/if_xl.c
@@ -1481,7 +1481,8 @@ xl_attach(dev)
 	 */
 	error = bus_dma_tag_create(NULL, 8, 0,
 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
-	    XL_RX_LIST_SZ, 1, XL_RX_LIST_SZ, 0, &sc->xl_ldata.xl_rx_tag);
+	    XL_RX_LIST_SZ, 1, XL_RX_LIST_SZ, 0, busdma_lock_mutex, &Giant,
+	    &sc->xl_ldata.xl_rx_tag);
 	if (error) {
 		printf("xl%d: failed to allocate rx dma tag\n", unit);
 		goto fail;
@@ -1512,7 +1513,8 @@ xl_attach(dev)
 
 	error = bus_dma_tag_create(NULL, 8, 0,
 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
-	    XL_TX_LIST_SZ, 1, XL_TX_LIST_SZ, 0, &sc->xl_ldata.xl_tx_tag);
+	    XL_TX_LIST_SZ, 1, XL_TX_LIST_SZ, 0, busdma_lock_mutex, &Giant,
+	    &sc->xl_ldata.xl_tx_tag);
 	if (error) {
 		printf("xl%d: failed to allocate tx dma tag\n", unit);
 		goto fail;
@@ -1546,7 +1548,8 @@ xl_attach(dev)
 	 */
 	error = bus_dma_tag_create(NULL, 1, 0,
 	    BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
-	    MCLBYTES * XL_MAXFRAGS, XL_MAXFRAGS, MCLBYTES, 0, &sc->xl_mtag);
+	    MCLBYTES * XL_MAXFRAGS, XL_MAXFRAGS, MCLBYTES, 0, busdma_lock_mutex,
+	    &Giant, &sc->xl_mtag);
 	if (error) {
 		printf("xl%d: failed to allocate mbuf dma tag\n", unit);
 		goto fail;