From 42d53b4ff7d61487d18274ebdf1f70c1aef6f122 Mon Sep 17 00:00:00 2001 From: Krzysztof Halasa Date: Fri, 8 Jan 2010 14:42:36 -0800 Subject: [PATCH] dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE and 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 Cc: David Miller Cc: Joerg Roedel Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/dma-debug.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/lib/dma-debug.c b/lib/dma-debug.c index cf90620..7d2f0b3 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -913,6 +913,9 @@ static void check_sync(struct device *dev, 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 " @@ -923,9 +926,6 @@ static void check_sync(struct device *dev, 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 " @@ -948,7 +948,6 @@ static void check_sync(struct device *dev, out: put_hash_bucket(bucket, &flags); - } void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, -- 2.7.4