Use atomic operations to increment and decrement the refcount

in busdma tags.  There are currently no tags shared accross
different drivers so this isn't needed at the moment, but it
will be required when we'll have a proper newbus method to get
the parent busdma tag.

6 files changed, 23 insertions, 22 deletions

diff --git a/sys/alpha/alpha/busdma_machdep.c b/sys/alpha/alpha/busdma_machdep.c
index 2075053..0b9ed6d 100644
--- a/sys/alpha/alpha/busdma_machdep.c
+++ b/sys/alpha/alpha/busdma_machdep.c
@@ -42,6 +42,7 @@
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
 
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/sgmap.h>
 #include <machine/md_var.h>
@@ -179,9 +180,8 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 			newtag->filterarg = parent->filterarg;
 			newtag->parent = parent->parent;
 		}
-		if (newtag->parent != NULL) {
-			parent->ref_count++;
-		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
 	}
 	
 	if (newtag->lowaddr < ptoa(Maxmem) && (flags & BUS_DMA_ALLOCNOW) != 0) {
@@ -228,7 +228,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
 			bus_dma_tag_t parent;
 
 			parent = dmat->parent;
-			dmat->ref_count--;
+			atomic_subtract_int(&dmat->ref_count, 1);
 			if (dmat->ref_count == 0) {
 				free(dmat, M_DEVBUF);
 			}
diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index d431ea0..4fe748c 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -42,6 +42,7 @@
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
 
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/md_var.h>
 
@@ -186,9 +187,8 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 			newtag->filterarg = parent->filterarg;
 			newtag->parent = parent->parent;
 		}
-		if (newtag->parent != NULL) {
-			parent->ref_count++;
-		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
 	}
 	
 	if (newtag->lowaddr < ptoa(Maxmem) && (flags & BUS_DMA_ALLOCNOW) != 0) {
@@ -235,7 +235,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
 			bus_dma_tag_t parent;
 
 			parent = dmat->parent;
-			dmat->ref_count--;
+			atomic_subtract_int(&dmat->ref_count, 1);
 			if (dmat->ref_count == 0) {
 				free(dmat, M_DEVBUF);
 				/*
diff --git a/sys/i386/i386/busdma_machdep.c b/sys/i386/i386/busdma_machdep.c
index d431ea0..4fe748c 100644
--- a/sys/i386/i386/busdma_machdep.c
+++ b/sys/i386/i386/busdma_machdep.c
@@ -42,6 +42,7 @@
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
 
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/md_var.h>
 
@@ -186,9 +187,8 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 			newtag->filterarg = parent->filterarg;
 			newtag->parent = parent->parent;
 		}
-		if (newtag->parent != NULL) {
-			parent->ref_count++;
-		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
 	}
 	
 	if (newtag->lowaddr < ptoa(Maxmem) && (flags & BUS_DMA_ALLOCNOW) != 0) {
@@ -235,7 +235,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
 			bus_dma_tag_t parent;
 
 			parent = dmat->parent;
-			dmat->ref_count--;
+			atomic_subtract_int(&dmat->ref_count, 1);
 			if (dmat->ref_count == 0) {
 				free(dmat, M_DEVBUF);
 				/*
diff --git a/sys/ia64/ia64/busdma_machdep.c b/sys/ia64/ia64/busdma_machdep.c
index 9b70d6c..3feacca 100644
--- a/sys/ia64/ia64/busdma_machdep.c
+++ b/sys/ia64/ia64/busdma_machdep.c
@@ -41,6 +41,7 @@
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
 
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/md_var.h>
 
@@ -175,9 +176,8 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 			newtag->filterarg = parent->filterarg;
 			newtag->parent = parent->parent;
 		}
-		if (newtag->parent != NULL) {
-			parent->ref_count++;
-		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
 	}
 	
 	if (newtag->lowaddr < ptoa(Maxmem) && (flags & BUS_DMA_ALLOCNOW) != 0) {
@@ -224,7 +224,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
 			bus_dma_tag_t parent;
 
 			parent = dmat->parent;
-			dmat->ref_count--;
+			atomic_subtract_int(&dmat->ref_count, 1);
 			if (dmat->ref_count == 0) {
 				free(dmat, M_DEVBUF);
 			}
diff --git a/sys/powerpc/powerpc/busdma_machdep.c b/sys/powerpc/powerpc/busdma_machdep.c
index 6c6dd36..63fdf71 100644
--- a/sys/powerpc/powerpc/busdma_machdep.c
+++ b/sys/powerpc/powerpc/busdma_machdep.c
@@ -51,6 +51,7 @@ static const char rcsid[] =
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
 
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/cpufunc.h>
 
@@ -133,9 +134,8 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
                         newtag->filterarg = parent->filterarg;
                         newtag->parent = parent->parent;
 		}
-                if (newtag->parent != NULL) {
-                        parent->ref_count++;
-		}
+		if (newtag->parent != NULL)
+			atomic_add_int(&parent->ref_count, 1);
 	}
 
 	*dmat = newtag;
@@ -154,7 +154,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
                         bus_dma_tag_t parent;
 			
                         parent = dmat->parent;
-                        dmat->ref_count--;
+                        atomic_subtract_int(&dmat->ref_count, 1);
                         if (dmat->ref_count == 0) {
                                 free(dmat, M_DEVBUF);
                                 /*
diff --git a/sys/sparc64/sparc64/bus_machdep.c b/sys/sparc64/sparc64/bus_machdep.c
index 588fc8c..11f7b78 100644
--- a/sys/sparc64/sparc64/bus_machdep.c
+++ b/sys/sparc64/sparc64/bus_machdep.c
@@ -128,6 +128,7 @@
 #include <vm/vm_map.h>
 
 #include <machine/asi.h>
+#include <machine/atomic.h>
 #include <machine/bus.h>
 #include <machine/bus_private.h>
 #include <machine/cache.h>
@@ -246,7 +247,7 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 		newtag->dt_boundary = ulmin(parent->dt_boundary,
 		    newtag->dt_boundary);
 	}
-	newtag->dt_parent->dt_ref_count++;
+	atomic_add_int(&newtag->dt_parent->dt_ref_count, 1);
 
 	*dmat = newtag;
 	return (0);
@@ -262,7 +263,7 @@ bus_dma_tag_destroy(bus_dma_tag_t dmat)
 			return (EBUSY);
 		while (dmat != NULL) {
 			parent = dmat->dt_parent;
-			dmat->dt_ref_count--;
+			atomic_subtract_int(&dmat->dt_ref_count, 1);
 			if (dmat->dt_ref_count == 0) {
 				free(dmat, M_DEVBUF);
 				/*