On 01/04/2024 04:21, Ping-Ke Shih wrote: >> >> I asked linux-usb and they said the two interfaces are probed >> and disconnected one at a time, so it should be fine without >> another mutex: >> >> https://lore.kernel.org/linux-usb/2024032907-smokeless-imperial-f3f9@gregkh/ > > Thanks for the clarification. Then, will you dynamically allocate mutex > by first interface with ref_cnt=1, and second interface obtains mutex from > first interface and increases ref_cnt=2? > > When USB disconnection, decrease ref_cnt and if ref_cnt==0 free the mutex > no matter which one disconnect first. > > My thinking above is the same as yours? > I did not consider using a ref_cnt variable. I made the first probe allocate the things and the first disconnect frees them: static struct usb_interface *rtl92du_get_other_intf(struct ieee80211_hw *hw) { struct usb_interface *intf; struct usb_device *udev; u8 other_interfaceindex; /* See SET_IEEE80211_DEV(hw, &intf->dev); in usb.c */ intf = container_of_const(wiphy_dev(hw->wiphy), struct usb_interface, dev); other_interfaceindex = 1 - intf->altsetting[0].desc.bInterfaceNumber; udev = interface_to_usbdev(intf); return usb_ifnum_to_if(udev, other_interfaceindex); } static int rtl92du_init_shared_data(struct ieee80211_hw *hw) { struct usb_interface *other_intf = rtl92du_get_other_intf(hw); struct rtl_priv *rtlpriv = rtl_priv(hw); struct rtl_priv *other_rtlpriv = NULL; struct ieee80211_hw *other_hw = NULL; if (other_intf) other_hw = usb_get_intfdata(other_intf); if (other_hw) { /* The other interface was already probed. */ other_rtlpriv = rtl_priv(other_hw); rtlpriv->curveindex_2g = other_rtlpriv->curveindex_2g; rtlpriv->curveindex_5g = other_rtlpriv->curveindex_5g; rtlpriv->mutex_for_power_on_off = other_rtlpriv->mutex_for_power_on_off; rtlpriv->mutex_for_hw_init = other_rtlpriv->mutex_for_hw_init; if (!rtlpriv->curveindex_2g || !rtlpriv->curveindex_5g || !rtlpriv->mutex_for_power_on_off || !rtlpriv->mutex_for_hw_init) return 1; return 0; } /* The other interface doesn't exist or was not probed yet. */ rtlpriv->curveindex_2g = kzalloc(TARGET_CHNL_NUM_2G * sizeof(*rtlpriv->curveindex_2g), GFP_KERNEL); rtlpriv->curveindex_5g = kzalloc(TARGET_CHNL_NUM_5G * sizeof(*rtlpriv->curveindex_5g), GFP_KERNEL); rtlpriv->mutex_for_power_on_off = kzalloc(sizeof(*rtlpriv->mutex_for_power_on_off), GFP_KERNEL); rtlpriv->mutex_for_hw_init = kzalloc(sizeof(*rtlpriv->mutex_for_hw_init), GFP_KERNEL); if (!rtlpriv->curveindex_2g || !rtlpriv->curveindex_5g || !rtlpriv->mutex_for_power_on_off || !rtlpriv->mutex_for_hw_init) { kfree(rtlpriv->curveindex_2g); kfree(rtlpriv->curveindex_5g); kfree(rtlpriv->mutex_for_power_on_off); kfree(rtlpriv->mutex_for_hw_init); rtlpriv->curveindex_2g = NULL; rtlpriv->curveindex_5g = NULL; rtlpriv->mutex_for_power_on_off = NULL; rtlpriv->mutex_for_hw_init = NULL; return 1; } mutex_init(rtlpriv->mutex_for_power_on_off); mutex_init(rtlpriv->mutex_for_hw_init); return 0; } static void rtl92du_deinit_shared_data(struct ieee80211_hw *hw) { struct usb_interface *other_intf = rtl92du_get_other_intf(hw); struct rtl_priv *rtlpriv = rtl_priv(hw); if (!other_intf || usb_get_intfdata(other_intf)) { /* The other interface doesn't exist or was not disconnected yet. */ kfree(rtlpriv->curveindex_2g); kfree(rtlpriv->curveindex_5g); if (rtlpriv->mutex_for_power_on_off) mutex_destroy(rtlpriv->mutex_for_power_on_off); if (rtlpriv->mutex_for_hw_init) mutex_destroy(rtlpriv->mutex_for_hw_init); kfree(rtlpriv->mutex_for_power_on_off); kfree(rtlpriv->mutex_for_hw_init); } } static int rtl92du_init_sw_vars(struct ieee80211_hw *hw) { const char *fw_name = "rtlwifi/rtl8192dufw.bin"; struct rtl_priv *rtlpriv = rtl_priv(hw); int err; if (rtl92du_init_shared_data(hw)) return 1; [...] return 0; } static void rtl92du_deinit_sw_vars(struct ieee80211_hw *hw) { struct rtl_priv *rtlpriv = rtl_priv(hw); kfree(rtlpriv->rtlhal.pfirmware); rtlpriv->rtlhal.pfirmware = NULL; rtl92du_deinit_shared_data(hw); }
