Reorder elements in the usb_host_interface structure to remove 8 bytes
of padding on 64 bit builds , and so shrink it's size to 40 bytes.
usb_interface_descriptor is a odd size which leaves a gap that is not
big enough to hold a pointer, so moving extralen into that gap removes
the need for more padding.
Signed-off-by: Richard Kennedy <rich...@rsk.demon.co.uk>
---
patch against v3.5-rc6
compiled and tested on x86_64
I've been running this patch for several weeks with no obvious problems.
This will allow the usb_host_interface array to be a bit smaller and should
better align with the cachelines.
regards
Richard
diff --git a/include/linux/usb.h b/include/linux/usb.h
index dea39dc..2abec02 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -77,14 +77,14 @@ struct usb_host_endpoint {
struct usb_host_interface {
struct usb_interface_descriptor desc;
+ int extralen;
+ unsigned char *extra; /* Extra descriptors */
/* array of desc.bNumEndpoint endpoints associated with this
* interface setting. these will be in no particular order.
*/
struct usb_host_endpoint *endpoint;
char *string; /* iInterface string, if present */
- unsigned char *extra; /* Extra descriptors */
- int extralen;
};
enum usb_interface_condition {
--
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