[PATCH v2 1/3] USB: musb: fix inefficient copy of unaligned buffers

From: Johan Hovold
Date: Thu Apr 23 2015 - 10:09:45 EST


Make sure only to copy any actual data rather than the whole buffer,
when releasing the temporary buffer used for unaligned non-isochronous
transfers.

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/musb/musb_host.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index c3d5fc9dfb5b..e1fb5d885c18 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -2512,6 +2512,7 @@ static void musb_free_temp_buffer(struct urb *urb)
{
enum dma_data_direction dir;
struct musb_temp_buffer *temp;
+ size_t length;

if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
return;
@@ -2522,8 +2523,12 @@ static void musb_free_temp_buffer(struct urb *urb)
data);

if (dir == DMA_FROM_DEVICE) {
- memcpy(temp->old_xfer_buffer, temp->data,
- urb->transfer_buffer_length);
+ 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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