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

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

116
drivers/usb/core/usb.c
View File

@ -74,6 +74,48 @@ MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
#define usb_autosuspend_delay 0
#endif
static bool match_endpoint(struct usb_endpoint_descriptor *epd,
struct usb_endpoint_descriptor **bulk_in,
struct usb_endpoint_descriptor **bulk_out,
struct usb_endpoint_descriptor **int_in,
struct usb_endpoint_descriptor **int_out)
{
switch (usb_endpoint_type(epd)) {
case USB_ENDPOINT_XFER_BULK:
if (usb_endpoint_dir_in(epd)) {
if (bulk_in && !*bulk_in) {
*bulk_in = epd;
break;
}
} else {
if (bulk_out && !*bulk_out) {
*bulk_out = epd;
break;
}
}
return false;
case USB_ENDPOINT_XFER_INT:
if (usb_endpoint_dir_in(epd)) {
if (int_in && !*int_in) {
*int_in = epd;
break;
}
} else {
if (int_out && !*int_out) {
*int_out = epd;
break;
}
}
return false;
default:
return false;
}
return (!bulk_in || *bulk_in) && (!bulk_out || *bulk_out) &&
(!int_in || *int_in) && (!int_out || *int_out);
}
/**
* usb_find_common_endpoints() -- look up common endpoint descriptors
@ -113,51 +155,49 @@ int usb_find_common_endpoints(struct usb_host_interface *alt,
for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
epd = &alt->endpoint[i].desc;
switch (usb_endpoint_type(epd)) {
case USB_ENDPOINT_XFER_BULK:
if (usb_endpoint_dir_in(epd)) {
if (bulk_in && !*bulk_in) {
*bulk_in = epd;
break;
}
} else {
if (bulk_out && !*bulk_out) {
*bulk_out = epd;
break;
}
}
continue;
case USB_ENDPOINT_XFER_INT:
if (usb_endpoint_dir_in(epd)) {
if (int_in && !*int_in) {
*int_in = epd;
break;
}
} else {
if (int_out && !*int_out) {
*int_out = epd;
break;
}
}
continue;
default:
continue;
}
if ((!bulk_in || *bulk_in) &&
(!bulk_out || *bulk_out) &&
(!int_in || *int_in) &&
(!int_out || *int_out)) {
if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
return 0;
}
}
return -ENXIO;
}
EXPORT_SYMBOL_GPL(usb_find_common_endpoints);
/**
* usb_find_common_endpoints_reverse() -- look up common endpoint descriptors
*
* Same as usb_find_common_endpoints(), but the endpoint descriptors are
* searched in reverse order (see usb_find_common_endpoints() for details).
*/
int 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)
{
struct usb_endpoint_descriptor *epd;
int i;
if (bulk_in)
*bulk_in = NULL;
if (bulk_out)
*bulk_out = NULL;
if (int_in)
*int_in = NULL;
if (int_out)
*int_out = NULL;
for (i = alt->desc.bNumEndpoints - 1; i >= 0; --i) {
epd = &alt->endpoint[i].desc;
if (match_endpoint(epd, bulk_in, bulk_out, int_in, int_out))
return 0;
}
return -ENXIO;
}
EXPORT_SYMBOL_GPL(usb_find_common_endpoints_reverse);
/**
* usb_find_alt_setting() - Given a configuration, find the alternate setting
* for the given interface.

35
include/linux/usb.h
View File

@ -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