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Subject[PATCH v2 2/3] USB: ehci-tegra: fix inefficient copy of unaligned buffers
Date
Make sure only to copy any actual data rather than the whole buffer,
when releasing the temporary buffer used for unaligned non-isochronous
transfers.

Compile-tested only.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/usb/host/ehci-tegra.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index ff9af29b4e9f..4031b372008e 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -304,6 +304,7 @@ struct dma_aligned_buffer {
static void free_dma_aligned_buffer(struct urb *urb)
{
struct dma_aligned_buffer *temp;
+ size_t length;

if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
return;
@@ -311,9 +312,14 @@ static void free_dma_aligned_buffer(struct urb *urb)
temp = container_of(urb->transfer_buffer,
struct dma_aligned_buffer, data);

- if (usb_urb_dir_in(urb))
- memcpy(temp->old_xfer_buffer, temp->data,
- urb->transfer_buffer_length);
+ if (usb_urb_dir_in(urb)) {
+ if (usb_pipeisoc(urb->pipe))
+ length = urb->transfer_buffer_length;
+ else
+ length = urb->actual_length;
+
+ memcpy(temp->old_xfer_buffer, temp->data, length);
+ }
urb->transfer_buffer = temp->old_xfer_buffer;
kfree(temp->kmalloc_ptr);

--
2.0.5


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