The message of commit 504e2b4ab97a ("dma-buf/udmabuf: skip redundant cpu sync to
fix cacheline EEXIST warning") says:
> The CPU sync at map/unmap time is also redundant for udmabuf:
> begin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit
> cache synchronization via dma_sync_sgtable_for_cpu/device() when CPU
> access is requested through the dma-buf interface.
This, however, does not apply to the first time begin_cpu_udmabuf() is
called on an udmabuf, in which case the implementation previously relied on
get_sg_table() to perform the cache synchronisation.
Ensure to call dma_sync_sgtable_for_cpu() in that case as well.
Fixes: 504e2b4ab97a ("dma-buf/udmabuf: skip redundant cpu sync to fix cacheline
EEXIST warning")
Signed-off-by: Robert Mader <[email protected]>
---
drivers/dma-buf/udmabuf.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index bced421c0d65..08f57bc1294d 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -224,21 +224,22 @@ static int begin_cpu_udmabuf(struct dma_buf *buf,
{
struct udmabuf *ubuf = buf->priv;
struct device *dev = ubuf->device->this_device;
- int ret = 0;
if (!ubuf->sg) {
ubuf->sg = get_sg_table(dev, buf, direction);
if (IS_ERR(ubuf->sg)) {
+ int ret;
+
ret = PTR_ERR(ubuf->sg);
ubuf->sg = NULL;
+ return ret;
} else {
ubuf->sg_dir = direction;
}
- } else {
- dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);
}
- return ret;
+ dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);
+ return 0;
}
static int end_cpu_udmabuf(struct dma_buf *buf,
--
2.54.0
