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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: Thomas Pugliese <thomas.pugliese@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -141,18 +141,26 @@ static int wusbhc_rh_port_reset(struct wusbhc *wusbhc, u8 port_idx)
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int wusbhc_rh_status_data(struct usb_hcd *usb_hcd, char *_buf)
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{
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struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
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size_t cnt, size;
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unsigned long *buf = (unsigned long *) _buf;
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size_t cnt, size, bits_set = 0;
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/* WE DON'T LOCK, see comment */
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size = wusbhc->ports_max + 1 /* hub bit */;
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size = (size + 8 - 1) / 8; /* round to bytes */
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for (cnt = 0; cnt < wusbhc->ports_max; cnt++)
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if (wusb_port_by_idx(wusbhc, cnt)->change)
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set_bit(cnt + 1, buf);
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else
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clear_bit(cnt + 1, buf);
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return size;
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/* round up to bytes. Hub bit is bit 0 so add 1. */
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size = DIV_ROUND_UP(wusbhc->ports_max + 1, 8);
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/* clear the output buffer. */
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memset(_buf, 0, size);
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/* set the bit for each changed port. */
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for (cnt = 0; cnt < wusbhc->ports_max; cnt++) {
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if (wusb_port_by_idx(wusbhc, cnt)->change) {
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const int bitpos = cnt+1;
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_buf[bitpos/8] |= (1 << (bitpos % 8));
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bits_set++;
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}
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}
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return bits_set ? size : 0;
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}
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EXPORT_SYMBOL_GPL(wusbhc_rh_status_data);
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