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wusbcore: fix root hub hub_status_data to only return > 0 if status has actually changed

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The hub_status_data function on the wireless USB root hub controller
(wusbhc_rh_status_data) always returns a positive value even if no ports
have changed.  This patch updates wusbhc_rh_status_data to only return a
positive value if the root hub status needs to be queried.  The current
implementation can also leave the upper bits of the port bitmap
uninitialized if wusbhc->ports_max is not one less than an even multiple
of 8.  This patch fixes that as well by initializing the buffer to 0.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Pugliese 2013-08-08 12:11:45 -05:00 committed by Greg Kroah-Hartman
parent 9841f37a1c
commit 467d296f47
1 changed files with 18 additions and 10 deletions
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28
drivers/usb/wusbcore/rh.c
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@ -141,18 +141,26 @@ static int wusbhc_rh_port_reset(struct wusbhc *wusbhc, u8 port_idx)
int wusbhc_rh_status_data(struct usb_hcd *usb_hcd, char *_buf)
{
struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
size_t cnt, size;
unsigned long *buf = (unsigned long *) _buf;
size_t cnt, size, bits_set = 0;
/* WE DON'T LOCK, see comment */
size = wusbhc->ports_max + 1 /* hub bit */;
size = (size + 8 - 1) / 8; /* round to bytes */
for (cnt = 0; cnt < wusbhc->ports_max; cnt++)
if (wusb_port_by_idx(wusbhc, cnt)->change)
set_bit(cnt + 1, buf);
else
clear_bit(cnt + 1, buf);
return size;
/* round up to bytes. Hub bit is bit 0 so add 1. */
size = DIV_ROUND_UP(wusbhc->ports_max + 1, 8);
/* clear the output buffer. */
memset(_buf, 0, size);
/* set the bit for each changed port. */
for (cnt = 0; cnt < wusbhc->ports_max; cnt++) {
if (wusb_port_by_idx(wusbhc, cnt)->change) {
const int bitpos = cnt+1;
_buf[bitpos/8] |= (1 << (bitpos % 8));
bits_set++;
}
}
return bits_set ? size : 0;
}
EXPORT_SYMBOL_GPL(wusbhc_rh_status_data);