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authorMiles Chen <miles.chen@mediatek.com>2017-02-22 15:40:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-22 16:41:26 -0800
commita5759b2bffa807a727cbf6790ecdc4df2ae8e4d4 (patch)
tree5173968a55e0108695940050b419cab596bc9d37 /lib
parentf42003917b4569a2f4f0c79c35e1e3df2859f81a (diff)
downloadlinux-a5759b2bffa807a727cbf6790ecdc4df2ae8e4d4.tar.gz
linux-a5759b2bffa807a727cbf6790ecdc4df2ae8e4d4.tar.xz
dma-debug: add comment for failed to check map error
Add comment for failure to check a map error to help driver developers. Link: http://lkml.kernel.org/r/1484622289-22085-1-git-send-email-miles.chen@mediatek.com Signed-off-by: Miles Chen <miles.chen@mediatek.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/dma-debug.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 8971370bfb16..60c57ec936db 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1155,6 +1155,11 @@ static void check_unmap(struct dma_debug_entry *ref)
dir2name[ref->direction]);
}
+ /*
+ * Drivers should use dma_mapping_error() to check the returned
+ * addresses of dma_map_single() and dma_map_page().
+ * If not, print this warning message. See Documentation/DMA-API.txt.
+ */
if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
err_printk(ref->dev, entry,
"DMA-API: device driver failed to check map error"