The patch titled
dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE and
has been added to the -mm tree. Its filename is
dma-debug-allow-dma_bidirectional-mappings-to-be-synced-with-dma_from_device-and.patch
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------------------------------------------------------
Subject: dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE and
From: Krzysztof Halasa <khc@xxxxxxxxx>
There is no need to perform full BIDIR sync (copying the buffers in case
of swiotlb and similar schemes) if we know that the owner (CPU or device)
hasn't altered the data.
Addresses the false-positive reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14169
Signed-off-by: Krzysztof Halasa <khc@xxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Joerg Roedel <joerg.roedel@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/dma-debug.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff -puN lib/dma-debug.c~dma-debug-allow-dma_bidirectional-mappings-to-be-synced-with-dma_from_device-and lib/dma-debug.c
--- a/lib/dma-debug.c~dma-debug-allow-dma_bidirectional-mappings-to-be-synced-with-dma_from_device-and
+++ a/lib/dma-debug.c
@@ -907,6 +907,9 @@ static void check_sync(struct device *de
ref->size);
}
+ if (entry->direction == DMA_BIDIRECTIONAL)
+ goto out;
+
if (ref->direction != entry->direction) {
err_printk(dev, entry, "DMA-API: device driver syncs "
"DMA memory with different direction "
@@ -917,9 +920,6 @@ static void check_sync(struct device *de
dir2name[ref->direction]);
}
- if (entry->direction == DMA_BIDIRECTIONAL)
- goto out;
-
if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
!(ref->direction == DMA_TO_DEVICE))
err_printk(dev, entry, "DMA-API: device driver syncs "
@@ -942,7 +942,6 @@ static void check_sync(struct device *de
out:
put_hash_bucket(bucket, &flags);
-
}
void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
_
Patches currently in -mm which might be from khc@xxxxxxxxx are
dma-debug-allow-dma_bidirectional-mappings-to-be-synced-with-dma_from_device-and.patch
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