wusbcore: fix root hub hub_status_data to only return > 0 if status has actually changed (467d296f) · Commits · 戴 / test

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>

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);

Admin message