2016-02-08 18:22:38

by Dan Carpenter

Subject: re: rtlwifi: fix broken VHT support

Hello Larry Finger,

The patch d76d65fd2695: "rtlwifi: fix broken VHT support" from Feb 1,
2016, leads to the following static checker warning:

drivers/net/wireless/realtek/rtlwifi/rc.c:144 _rtl_rc_rate_set_series()
warn: impossible condition '(wireless_mode == 256) => (0-255 == 256)'

drivers/net/wireless/realtek/rtlwifi/rc.c
135 if (sgi_20 || sgi_40 || sgi_80)
136 rate->flags |= IEEE80211_TX_RC_SHORT_GI;
137 if (sta && sta->ht_cap.ht_supported &&
138 ((wireless_mode == WIRELESS_MODE_N_5G) ||
139 (wireless_mode == WIRELESS_MODE_N_24G)))
140 rate->flags |= IEEE80211_TX_RC_MCS;
141 if (sta && sta->vht_cap.vht_supported &&
142 (wireless_mode == WIRELESS_MODE_AC_5G ||
143 wireless_mode == WIRELESS_MODE_AC_24G ||
144 wireless_mode == WIRELESS_MODE_AC_ONLY))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Not possible. sta_entry->wireless_mode is u8 and WIRELESS_MODE_AC_ONLY
is 0x100.

145 rate->flags |= IEEE80211_TX_RC_VHT_MCS;
146 }
147 }


regards,
dan carpenter

2016-02-08 19:52:06

by Larry Finger

Subject: Re: rtlwifi: fix broken VHT support

On 02/08/2016 12:22 PM, Dan Carpenter wrote:
> Hello Larry Finger,
>
> The patch d76d65fd2695: "rtlwifi: fix broken VHT support" from Feb 1,
> 2016, leads to the following static checker warning:
>
> drivers/net/wireless/realtek/rtlwifi/rc.c:144 _rtl_rc_rate_set_series()
> warn: impossible condition '(wireless_mode == 256) => (0-255 == 256)'
>
> drivers/net/wireless/realtek/rtlwifi/rc.c
> 135 if (sgi_20 || sgi_40 || sgi_80)
> 136 rate->flags |= IEEE80211_TX_RC_SHORT_GI;
> 137 if (sta && sta->ht_cap.ht_supported &&
> 138 ((wireless_mode == WIRELESS_MODE_N_5G) ||
> 139 (wireless_mode == WIRELESS_MODE_N_24G)))
> 140 rate->flags |= IEEE80211_TX_RC_MCS;
> 141 if (sta && sta->vht_cap.vht_supported &&
> 142 (wireless_mode == WIRELESS_MODE_AC_5G ||
> 143 wireless_mode == WIRELESS_MODE_AC_24G ||
> 144 wireless_mode == WIRELESS_MODE_AC_ONLY))
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Not possible. sta_entry->wireless_mode is u8 and WIRELESS_MODE_AC_ONLY
> is 0x100.
>
> 145 rate->flags |= IEEE80211_TX_RC_VHT_MCS;
> 146 }
> 147 }
>
>

Dan,

Thanks for the heads-up. Obviously, wireless_mode needs to be u16, but I will
need some time to consider any side effects as the underlying variable in the
private space is used by several of the rtlwifi family.

Larry