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USB: core: add helpers to retrieve endpoints in reverse order

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Several drivers have implemented their endpoint look-up loops in such a
way that they have picked the last endpoint descriptor of the specified
type should more than one such descriptor exist.

To avoid any regressions, add corresponding helpers to lookup endpoints
by searching the endpoint descriptors in reverse order.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold
2017-03-17 11:35:31 +01:00
committed by Greg Kroah-Hartman
parent 66a359390e
commit 279daf4e05
2 changed files with 113 additions and 38 deletions
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35
include/linux/usb.h
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@@ -106,6 +106,13 @@ usb_find_common_endpoints(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **int_in,
struct usb_endpoint_descriptor **int_out);
int __must_check
usb_find_common_endpoints_reverse(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **bulk_in,
struct usb_endpoint_descriptor **bulk_out,
struct usb_endpoint_descriptor **int_in,
struct usb_endpoint_descriptor **int_out);
static inline int __must_check
usb_find_bulk_in_endpoint(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **bulk_in)
@@ -134,6 +141,34 @@ usb_find_int_out_endpoint(struct usb_host_interface *alt,
return usb_find_common_endpoints(alt, NULL, NULL, NULL, int_out);
}
static inline int __must_check
usb_find_last_bulk_in_endpoint(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **bulk_in)
{
return usb_find_common_endpoints_reverse(alt, bulk_in, NULL, NULL, NULL);
}
static inline int __must_check
usb_find_last_bulk_out_endpoint(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **bulk_out)
{
return usb_find_common_endpoints_reverse(alt, NULL, bulk_out, NULL, NULL);
}
static inline int __must_check
usb_find_last_int_in_endpoint(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **int_in)
{
return usb_find_common_endpoints_reverse(alt, NULL, NULL, int_in, NULL);
}
static inline int __must_check
usb_find_last_int_out_endpoint(struct usb_host_interface *alt,
struct usb_endpoint_descriptor **int_out)
{
return usb_find_common_endpoints_reverse(alt, NULL, NULL, NULL, int_out);
}
/**
* struct usb_interface - what usb device drivers talk to
* @altsetting: array of interface structures, one for each alternate