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Commit 467d296f authored by Thomas Pugliese's avatar Thomas Pugliese Committed by Greg Kroah-Hartman
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wusbcore: fix root hub hub_status_data to only return > 0 if status has actually changed 



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: default avatarThomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9841f37a

drivers/usb/wusbcore/rh.c

+18 −10
Original line number Diff line number Diff line
@@ -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);