If busdma is being used to realign dynamic buffers and the alignment is set to

PAGE_SIZE or less, the bounce page counting logic was flawed and wouldn't
reserve any pages.  Adjust to be correct.  Review of other architectures is
forthcoming.

Submitted by: Joseph Golio

2 files changed, 4 insertions, 4 deletions

diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index 321c49e..c9475d5 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -598,14 +598,14 @@ _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 		 * Count the number of bounce pages
 		 * needed in order to complete this transfer
 		 */
-		vaddr = trunc_page((vm_offset_t)buf);
+		vaddr = (vm_offset_t)buf;
 		vendaddr = (vm_offset_t)buf + buflen;
 
 		while (vaddr < vendaddr) {
 			paddr = pmap_kextract(vaddr);
 			if (run_filter(dmat, paddr) != 0)
 				map->pagesneeded++;
-			vaddr += PAGE_SIZE;
+			vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 		}
 		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 	}
diff --git a/sys/i386/i386/busdma_machdep.c b/sys/i386/i386/busdma_machdep.c
index 383061b..0c76c7a 100644
--- a/sys/i386/i386/busdma_machdep.c
+++ b/sys/i386/i386/busdma_machdep.c
@@ -585,7 +585,7 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 		 * Count the number of bounce pages
 		 * needed in order to complete this transfer
 		 */
-		vaddr = trunc_page((vm_offset_t)buf);
+		vaddr = (vm_offset_t)buf;
 		vendaddr = (vm_offset_t)buf + buflen;
 
 		while (vaddr < vendaddr) {
@@ -594,7 +594,7 @@ _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 			    run_filter(dmat, paddr) != 0) {
 				map->pagesneeded++;
 			}
-			vaddr += PAGE_SIZE;
+			vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 		}
 		CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 	}