in _bus_dmamem_map use PMAP_CANFAIL for mapping in the pages.

bus_dmamem_map can fail for a myriad of reasons already, so panicing if
pmap fails is just impolite. other archs will be forthcoming.

ok krw@, art@ before lock

1 files changed, 24 insertions, 5 deletions

diff --git a/sys/arch/i386/i386/bus_dma.c b/sys/arch/i386/i386/bus_dma.c
index 973bf82a706..27cf4d36317 100644
--- a/sys/arch/i386/i386/bus_dma.c
+++ b/sys/arch/i386/i386/bus_dma.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bus_dma.c,v 1.20 2010/03/25 22:44:57 oga Exp $	*/
+/*	$OpenBSD: bus_dma.c,v 1.21 2010/03/27 00:37:15 oga Exp $	*/
 /*-
  * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -416,9 +416,10 @@ int
 _bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
     size_t size, caddr_t *kvap, int flags)
 {
-	vaddr_t va;
+	vaddr_t va, sva;
+	size_t ssize;
 	bus_addr_t addr;
-	int curseg, pmapflags = 0;
+	int curseg, pmapflags = 0, ret;
 
 	if (flags & BUS_DMA_NOCACHE)
 		pmapflags |= PMAP_NOCACHE;
@@ -430,15 +431,33 @@ _bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
 
 	*kvap = (caddr_t)va;
 
+	sva = va;
+	ssize = size;
 	for (curseg = 0; curseg < nsegs; curseg++) {
 		for (addr = segs[curseg].ds_addr;
 		    addr < (segs[curseg].ds_addr + segs[curseg].ds_len);
 		    addr += PAGE_SIZE, va += PAGE_SIZE, size -= PAGE_SIZE) {
 			if (size == 0)
 				panic("_bus_dmamem_map: size botch");
-			pmap_enter(pmap_kernel(), va, addr | pmapflags,
+			/*
+			 * we don't want pmap to panic here if it can't
+			 * alloc
+			 */
+			ret = pmap_enter(pmap_kernel(), va, addr | pmapflags,
 			    VM_PROT_READ | VM_PROT_WRITE, VM_PROT_READ |
-			    VM_PROT_WRITE | PMAP_WIRED);
+			    VM_PROT_WRITE | PMAP_WIRED | PMAP_CANFAIL);
+			if (ret) {
+				/*
+				 * Clean up after ourselves.
+				 * XXX uvm_wait on WAITOK
+				 */
+				pmap_remove(pmap_kernel(), sva, va - PAGE_SIZE);
+				pmap_update(pmap_kernel());
+
+				uvm_km_free(kernel_map, va, ssize);
+				return (ret);
+			}
+
 		}
 	}
 	pmap_update(pmap_kernel());