Remove the 'needbounce' variable from the _bus_dmamap_load_buffer()

routine.  It is not needed as the existing tests for segment coalescing
already handle bounced addresses and it prevents legal segment coalescing
in certain edge cases.

MFC after:	1 week
Reviewed by:	scottl

4 files changed, 12 insertions, 29 deletions

diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index b726fbbda271..321c49ebf591 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -580,7 +580,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 	bus_addr_t curaddr, lastaddr, baddr, bmask;
 	vm_offset_t vaddr;
 	bus_addr_t paddr;
-	int needbounce = 0;
 	int seg;
 
 	if (map == NULL)
@@ -604,10 +603,8 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 
 		while (vaddr < vendaddr) {
 			paddr = pmap_kextract(vaddr);
-			if (run_filter(dmat, paddr) != 0) {
-				needbounce = 1;
+			if (run_filter(dmat, paddr) != 0)
 				map->pagesneeded++;
-			}
 			vaddr += PAGE_SIZE;
 		}
 		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
@@ -679,7 +676,7 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 			segs[seg].ds_len = sgsize;
 			first = 0;
 		} else {
-			if (needbounce == 0 && curaddr == lastaddr &&
+			if (curaddr == lastaddr &&
 			    (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 			    (dmat->boundary == 0 ||
 			     (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
diff --git a/sys/arm/arm/busdma_machdep.c b/sys/arm/arm/busdma_machdep.c
index 2044e2a1dece..6c8195ba8284 100644
--- a/sys/arm/arm/busdma_machdep.c
+++ b/sys/arm/arm/busdma_machdep.c
@@ -664,12 +664,11 @@ bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 
 static int
 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
-			bus_size_t buflen, int flags, int *nb)
+			bus_size_t buflen, int flags)
 {
 	vm_offset_t vaddr;
 	vm_offset_t vendaddr;
 	bus_addr_t paddr;
-	int needbounce = *nb;
 
 	if ((map->pagesneeded == 0)) {
 		CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
@@ -687,10 +686,8 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 		while (vaddr < vendaddr) {
 			paddr = pmap_kextract(vaddr);
 			if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
-			    run_filter(dmat, paddr) != 0) {
-				needbounce = 1;
+			    run_filter(dmat, paddr) != 0)
 				map->pagesneeded++;
-			}
 			vaddr += PAGE_SIZE;
 		}
 		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
@@ -716,7 +713,6 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 		mtx_unlock(&bounce_lock);
 	}
 
-	*nb = needbounce;
 	return (0);
 }
 
@@ -739,14 +735,12 @@ bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dma_segment_t *segs,
 	pd_entry_t *pde;
 	pt_entry_t pte;
 	pt_entry_t *ptep;
-	int needbounce = 0;
 
 	lastaddr = *lastaddrp;
 	bmask = ~(dmat->boundary - 1);
 
 	if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
-		error = _bus_dmamap_count_pages(dmat, map, buf, buflen, flags,
-		    &needbounce);
+		error = _bus_dmamap_count_pages(dmat, map, buf, buflen, flags);
 		if (error)
 			return (error);
 	}
@@ -840,7 +834,7 @@ bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dma_segment_t *segs,
 		 * Insert chunk into a segment, coalescing with
 		 * the previous segment if possible.
 		 */
-		if (needbounce == 0 && seg >= 0 && curaddr == lastaddr &&
+		if (seg >= 0 && curaddr == lastaddr &&
 		    (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 		    (dmat->boundary == 0 ||
 		     (segs[seg].ds_addr & bmask) == 
diff --git a/sys/i386/i386/busdma_machdep.c b/sys/i386/i386/busdma_machdep.c
index 90f8848d13fd..383061b78b60 100644
--- a/sys/i386/i386/busdma_machdep.c
+++ b/sys/i386/i386/busdma_machdep.c
@@ -142,7 +142,7 @@ static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 int _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
-			    bus_size_t buflen, int flags, int *nb);
+			    bus_size_t buflen, int flags);
 
 /*
  * Return true if a match is made.
@@ -569,12 +569,11 @@ bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 
 int
 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
-			bus_size_t buflen, int flags, int *nb)
+			bus_size_t buflen, int flags)
 {
 	vm_offset_t vaddr;
 	vm_offset_t vendaddr;
 	bus_addr_t paddr;
-	int needbounce = *nb;
 
 	if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 		CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
@@ -593,7 +592,6 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 			paddr = pmap_kextract(vaddr);
 			if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 			    run_filter(dmat, paddr) != 0) {
-				needbounce = 1;
 				map->pagesneeded++;
 			}
 			vaddr += PAGE_SIZE;
@@ -624,7 +622,6 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 		mtx_unlock(&bounce_lock);
 	}
 
-	*nb = needbounce;
 	return (0);
 }
 
@@ -648,15 +645,13 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 	bus_size_t sgsize;
 	bus_addr_t curaddr, lastaddr, baddr, bmask;
 	vm_offset_t vaddr;
-	int needbounce = 0;
 	int seg, error;
 
 	if (map == NULL)
 		map = &nobounce_dmamap;
 
 	if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
-		error = _bus_dmamap_count_pages(dmat, map, buf, buflen, flags,
-		    &needbounce);
+		error = _bus_dmamap_count_pages(dmat, map, buf, buflen, flags);
 		if (error)
 			return (error);
 	}
@@ -705,7 +700,7 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 			segs[seg].ds_len = sgsize;
 			first = 0;
 		} else {
-			if (needbounce == 0 && curaddr == lastaddr &&
+			if (curaddr == lastaddr &&
 			    (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 			    (dmat->boundary == 0 ||
 			     (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
diff --git a/sys/ia64/ia64/busdma_machdep.c b/sys/ia64/ia64/busdma_machdep.c
index 5ef2e5361986..8dd4a9bcf8bd 100644
--- a/sys/ia64/ia64/busdma_machdep.c
+++ b/sys/ia64/ia64/busdma_machdep.c
@@ -503,7 +503,6 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 	bus_addr_t curaddr, lastaddr, baddr, bmask;
 	vm_offset_t vaddr;
 	bus_addr_t paddr;
-	int needbounce = 0;
 	int seg;
 	pmap_t pmap;
 
@@ -529,10 +528,8 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 
 		while (vaddr < vendaddr) {
 			paddr = pmap_kextract(vaddr);
-			if (run_filter(dmat, paddr, 0) != 0) {
-				needbounce = 1;
+			if (run_filter(dmat, paddr, 0) != 0)
 				map->pagesneeded++;
-			}
 			vaddr += PAGE_SIZE;
 		}
 	}
@@ -604,7 +601,7 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 			segs[seg].ds_len = sgsize;
 			first = 0;
 		} else {
-			if (!needbounce && curaddr == lastaddr &&
+			if (curaddr == lastaddr &&
 			    (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 			    (dmat->boundary == 0 ||
 			     (segs[seg].ds_addr & bmask) == (curaddr & bmask)))