2 files changed, 18 insertions, 8 deletions

diff --git a/sys/x86/include/x86_var.h b/sys/x86/include/x86_var.h
index 47b630d076d2..78acadd2b733 100644
--- a/sys/x86/include/x86_var.h
+++ b/sys/x86/include/x86_var.h
@@ -38,7 +38,6 @@
 
 extern	long	Maxmem;
 extern	u_int	basemem;
-extern	int	busdma_swi_pending;
 extern	u_int	cpu_exthigh;
 extern	u_int	cpu_feature;
 extern	u_int	cpu_feature2;
@@ -115,7 +114,6 @@ typedef void alias_for_inthand_t(void);
 
 bool	acpi_get_fadt_bootflags(uint16_t *flagsp);
 void	*alloc_fpusave(int flags);
-void	busdma_swi(void);
 u_int	cpu_auxmsr(void);
 vm_paddr_t cpu_getmaxphyaddr(void);
 bool	cpu_mwait_usable(void);
diff --git a/sys/x86/x86/busdma_bounce.c b/sys/x86/x86/busdma_bounce.c
index ee6d2d50d542..7afa4cf6e2aa 100644
--- a/sys/x86/x86/busdma_bounce.c
+++ b/sys/x86/x86/busdma_bounce.c
@@ -90,8 +90,6 @@ struct bounce_page {
 	STAILQ_ENTRY(bounce_page) links;
 };
 
-int busdma_swi_pending;
-
 struct bounce_zone {
 	STAILQ_ENTRY(bounce_zone) links;
 	STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
@@ -115,6 +113,7 @@ static struct mtx bounce_lock;
 static int total_bpages;
 static int busdma_zonecount;
 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
+static void *busdma_ih;
 
 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
     "Busdma parameters");
@@ -1311,6 +1310,7 @@ free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 {
 	struct bus_dmamap *map;
 	struct bounce_zone *bz;
+	bool schedule_swi;
 
 	bz = dmat->bounce_zone;
 	bpage->datavaddr = 0;
@@ -1325,6 +1325,7 @@ free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 		bpage->busaddr &= ~PAGE_MASK;
 	}
 
+	schedule_swi = false;
 	mtx_lock(&bounce_lock);
 	STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
 	bz->free_bpages++;
@@ -1334,16 +1335,17 @@ free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 			STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 			STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 			    map, links);
-			busdma_swi_pending = 1;
 			bz->total_deferred++;
-			swi_sched(vm_ih, 0);
+			schedule_swi = true;
 		}
 	}
 	mtx_unlock(&bounce_lock);
+	if (schedule_swi)
+		swi_sched(busdma_ih, 0);
 }
 
-void
-busdma_swi(void)
+static void
+busdma_swi(void *dummy __unused)
 {
 	bus_dma_tag_t dmat;
 	struct bus_dmamap *map;
@@ -1363,6 +1365,16 @@ busdma_swi(void)
 	mtx_unlock(&bounce_lock);
 }
 
+static void
+start_busdma_swi(void *dummy __unused)
+{
+	if (swi_add(NULL, "busdma", busdma_swi, NULL, SWI_BUSDMA, INTR_MPSAFE,
+	    &busdma_ih))
+		panic("died while creating busdma swi ithread");
+}
+SYSINIT(start_busdma_swi, SI_SUB_SOFTINTR, SI_ORDER_ANY, start_busdma_swi,
+    NULL);
+
 struct bus_dma_impl bus_dma_bounce_impl = {
 	.tag_create = bounce_bus_dma_tag_create,
 	.tag_destroy = bounce_bus_dma_tag_destroy,