From 80c343b215be744387082981af1857953d59caaa Mon Sep 17 00:00:00 2001
From: cognet <cognet@FreeBSD.org>
Date: Mon, 9 Feb 2009 18:03:31 +0000
Subject: [PATCH] The bounce zone sees its page number increased if multiple
 dma maps use it in the same dma tag. However, it can happen multiple dma tags
 share the same bounce zone too, so add a per-bounce zone map counter, and
 check it instead of the dma tag map counter, to know if we have to alloc more
 pages.

Reported by:	miwi
Reviewed by:	scottl
---
 sys/amd64/amd64/busdma_machdep.c | 7 ++++++-
 sys/arm/arm/busdma_machdep.c     | 7 ++++++-
 sys/i386/i386/busdma_machdep.c   | 7 ++++++-
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/sys/amd64/amd64/busdma_machdep.c b/sys/amd64/amd64/busdma_machdep.c
index c8f689abc94f..c50fcc3cef9e 100644
--- a/sys/amd64/amd64/busdma_machdep.c
+++ b/sys/amd64/amd64/busdma_machdep.c
@@ -93,6 +93,7 @@ struct bounce_zone {
 	int		active_bpages;
 	int		total_bounced;
 	int		total_deferred;
+	int		map_count;
 	bus_size_t	alignment;
 	bus_size_t	boundary;
 	bus_addr_t	lowaddr;
@@ -418,7 +419,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 		else
 			maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
 		if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
-		 || (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
+		 || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 			int pages;
 
 			pages = MAX(atop(dmat->maxsize), 1);
@@ -434,6 +435,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 				error = 0;
 			}
 		}
+		bz->map_count++;
 	} else {
 		*mapp = NULL;
 	}
@@ -457,6 +459,8 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 			    __func__, dmat, EBUSY);
 			return (EBUSY);
 		}
+		if (dmat->bounce_zone)
+			dmat->bounce_zone->map_count--;
 		free(map, M_DEVBUF);
 	}
 	dmat->map_count--;
@@ -989,6 +993,7 @@ alloc_bounce_zone(bus_dma_tag_t dmat)
 	bz->lowaddr = dmat->lowaddr;
 	bz->alignment = dmat->alignment;
 	bz->boundary = dmat->boundary;
+	bz->map_count = 0;
 	snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
 	busdma_zonecount++;
 	snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
diff --git a/sys/arm/arm/busdma_machdep.c b/sys/arm/arm/busdma_machdep.c
index fb14ab096f47..a7381724682d 100644
--- a/sys/arm/arm/busdma_machdep.c
+++ b/sys/arm/arm/busdma_machdep.c
@@ -112,6 +112,7 @@ struct bounce_zone {
 	int		active_bpages;
 	int		total_bounced;
 	int		total_deferred;
+	int		map_count;
 	bus_size_t	alignment;
 	bus_size_t	boundary;
 	bus_addr_t	lowaddr;
@@ -523,7 +524,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 		 */
 		maxpages = MAX_BPAGES;
 		if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
-		 || (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
+		 || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 			int pages;
 
 			pages = MAX(atop(dmat->maxsize), 1);
@@ -539,6 +540,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 				error = 0;
 			}
 		}
+		bz->map_count++;
 	}
 	CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 	    __func__, dmat, dmat->flags, error);
@@ -560,6 +562,8 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 		    __func__, dmat, EBUSY);
 		return (EBUSY);
 	}
+	if (dmat->bounce_zone)
+		dmat->bounce_zone->map_count--;
         dmat->map_count--;
 	CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
         return (0);
@@ -1277,6 +1281,7 @@ alloc_bounce_zone(bus_dma_tag_t dmat)
 	bz->lowaddr = dmat->lowaddr;
 	bz->alignment = dmat->alignment;
 	bz->boundary = dmat->boundary;
+	bz->map_count = 0;
 	snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
 	busdma_zonecount++;
 	snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
diff --git a/sys/i386/i386/busdma_machdep.c b/sys/i386/i386/busdma_machdep.c
index 04844f98dcad..d4aa9b51c1c0 100644
--- a/sys/i386/i386/busdma_machdep.c
+++ b/sys/i386/i386/busdma_machdep.c
@@ -98,6 +98,7 @@ struct bounce_zone {
 	int		active_bpages;
 	int		total_bounced;
 	int		total_deferred;
+	int		map_count;
 	bus_size_t	alignment;
 	bus_size_t	boundary;
 	bus_addr_t	lowaddr;
@@ -431,7 +432,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 		else
 			maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
 		if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
-		 || (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
+		 || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 			int pages;
 
 			pages = MAX(atop(dmat->maxsize), 1);
@@ -447,6 +448,7 @@ bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 				error = 0;
 			}
 		}
+		bz->map_count++;
 	} else {
 		*mapp = NULL;
 	}
@@ -470,6 +472,8 @@ bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 			    __func__, dmat, EBUSY);
 			return (EBUSY);
 		}
+		if (dmat->bounce_zone)
+			dmat->bounce_zone->map_count--;
 		free(map, M_DEVBUF);
 	}
 	dmat->map_count--;
@@ -1007,6 +1011,7 @@ alloc_bounce_zone(bus_dma_tag_t dmat)
 	bz->lowaddr = dmat->lowaddr;
 	bz->alignment = dmat->alignment;
 	bz->boundary = dmat->boundary;
+	bz->map_count = 0;
 	snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
 	busdma_zonecount++;
 	snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);