Messages in this thread | | | Date | Fri, 13 Oct 2017 23:48:25 +0200 (CEST) | From | Julia Lawall <> | Subject | Re: drivers/staging/rtlwifi/base.c:920:7-9: WARNING: possible condition with no effect (if == else) |
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On Fri, 13 Oct 2017, Larry Finger wrote:
> Julia, > > On 10/13/2017 08:55 AM, Julia Lawall wrote: > > It seems that the then and else branches of the conditions on lines 920 > > and 932 are the same. > > I think line 923 should be using RTL_RC_VHT_RATE_2SS_MCS8 rather than > RTL_RC_VHT_RATE_2SS_MCS9, but I have sent an inquiry to my contact at Realtek > to check.
OK, thanks. The realtek code has a surprisingly large number of these kinds of problems, for example, the following from (drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtc8723b2ant.c):
if ((wifi_rssi_state == BTC_RSSI_STATE_HIGH) || (wifi_rssi_state == BTC_RSSI_STATE_STAY_HIGH)) { btc8723b2ant_sw_mechanism(btcoexist, true, false, false, false); } else { btc8723b2ant_sw_mechanism(btcoexist, true, false, false, false); }
I wondered if the code is generated, and the generator has a policy of just doing the last "then" branch if all of the known tests fail.
I could send a complete list of such issues, if they are of interest.
julia
> > Thanks, > > Larry > > > On Fri, 13 Oct 2017, kbuild test robot wrote: > > > > > CC: kbuild-all@01.org > > > CC: linux-kernel@vger.kernel.org > > > TO: Larry Finger <Larry.Finger@lwfinger.net> > > > CC: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org> > > > > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > master > > > head: 3d7882769b5dc929690f96e0c318c29b97f51018 > > > commit: 5b5ab4cb5cda824ef59e0511ac5d585f35f1a1a6 staging: r8822be: Add > > > Makefiles and Kconfig for new driver > > > date: 8 weeks ago > > > :::::: branch date: 12 hours ago > > > :::::: commit date: 8 weeks ago > > > > > > > > drivers/staging/rtlwifi/base.c:920:7-9: WARNING: possible condition > > > > > with no effect (if == else) > > > drivers/staging/rtlwifi/base.c:932:7-9: WARNING: possible condition > > > with no effect (if == else) > > > > > > # > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5b5ab4cb5cda824ef59e0511ac5d585f35f1a1a6 > > > git remote add linus > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > > git remote update linus > > > git checkout 5b5ab4cb5cda824ef59e0511ac5d585f35f1a1a6 > > > vim +920 drivers/staging/rtlwifi/base.c > > > > > > 56bde846 Ping-Ke Shih 2017-08-17 905 > > > 56bde846 Ping-Ke Shih 2017-08-17 906 static u8 > > > _rtl_get_vht_highest_n_rate(struct ieee80211_hw *hw, > > > 56bde846 Ping-Ke Shih 2017-08-17 907 > > > struct ieee80211_sta *sta) > > > 56bde846 Ping-Ke Shih 2017-08-17 908 { > > > 56bde846 Ping-Ke Shih 2017-08-17 909 struct rtl_priv *rtlpriv = > > > rtl_priv(hw); > > > 56bde846 Ping-Ke Shih 2017-08-17 910 struct rtl_phy *rtlphy = > > > &rtlpriv->phy; > > > 56bde846 Ping-Ke Shih 2017-08-17 911 u8 hw_rate; > > > 56bde846 Ping-Ke Shih 2017-08-17 912 u16 tx_mcs_map = > > > le16_to_cpu(sta->vht_cap.vht_mcs.tx_mcs_map); > > > 56bde846 Ping-Ke Shih 2017-08-17 913 > > > 56bde846 Ping-Ke Shih 2017-08-17 914 if ((get_rf_type(rtlphy) == > > > RF_2T2R) && > > > 56bde846 Ping-Ke Shih 2017-08-17 915 (tx_mcs_map & 0x000c) != > > > 0x000c) { > > > 56bde846 Ping-Ke Shih 2017-08-17 916 if ((tx_mcs_map & > > > 0x000c) >> 2 == > > > 56bde846 Ping-Ke Shih 2017-08-17 917 > > > IEEE80211_VHT_MCS_SUPPORT_0_7) > > > 56bde846 Ping-Ke Shih 2017-08-17 918 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 919 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_2SS_MCS7]; > > > 56bde846 Ping-Ke Shih 2017-08-17 @920 else if ((tx_mcs_map > > > & 0x000c) >> 2 == > > > 56bde846 Ping-Ke Shih 2017-08-17 921 > > > IEEE80211_VHT_MCS_SUPPORT_0_8) > > > 56bde846 Ping-Ke Shih 2017-08-17 922 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 923 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_2SS_MCS9]; > > > 56bde846 Ping-Ke Shih 2017-08-17 924 else > > > 56bde846 Ping-Ke Shih 2017-08-17 925 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 926 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_2SS_MCS9]; > > > 56bde846 Ping-Ke Shih 2017-08-17 927 } else { > > > 56bde846 Ping-Ke Shih 2017-08-17 928 if ((tx_mcs_map & > > > 0x0003) == > > > 56bde846 Ping-Ke Shih 2017-08-17 929 > > > IEEE80211_VHT_MCS_SUPPORT_0_7) > > > 56bde846 Ping-Ke Shih 2017-08-17 930 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 931 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_1SS_MCS7]; > > > 56bde846 Ping-Ke Shih 2017-08-17 932 else if ((tx_mcs_map > > > & 0x0003) == > > > 56bde846 Ping-Ke Shih 2017-08-17 933 > > > IEEE80211_VHT_MCS_SUPPORT_0_8) > > > 56bde846 Ping-Ke Shih 2017-08-17 934 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 935 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_1SS_MCS9]; > > > 56bde846 Ping-Ke Shih 2017-08-17 936 else > > > 56bde846 Ping-Ke Shih 2017-08-17 937 hw_rate = > > > 56bde846 Ping-Ke Shih 2017-08-17 938 > > > rtlpriv->cfg->maps[RTL_RC_VHT_RATE_1SS_MCS9]; > > > 56bde846 Ping-Ke Shih 2017-08-17 939 } > > > 56bde846 Ping-Ke Shih 2017-08-17 940 > > > 56bde846 Ping-Ke Shih 2017-08-17 941 return hw_rate; > > > 56bde846 Ping-Ke Shih 2017-08-17 942 } > > > 56bde846 Ping-Ke Shih 2017-08-17 943 > > > > > > :::::: The code at line 920 was first introduced by commit > > > :::::: 56bde846304ea05d5f8c8de0e3a42627a7a92be6 staging: r8822be: Add > > > existing rtlwifi and rtl_pci parts for new driver > > > > > > :::::: TO: Ping-Ke Shih <pkshih@realtek.com> > > > :::::: CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > > > > --- > > > 0-DAY kernel test infrastructure Open Source Technology > > > Center > > > https://lists.01.org/pipermail/kbuild-all Intel > > > Corporation > > > > > > >
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