Re: [Outreachy kernel] [PATCH] staging: rtl8723bs: os_dep: Remove typecast in kfree

[Nachammai Karuppiah <nachukannan@gmail.com>]

On Tue, Oct 8, 2019 at 1:53 AM Julia Lawall <julia.lawall@lip6.fr> wrote:
>
>
>
> On Mon, 7 Oct 2019, Nachammai Karuppiah wrote:
>
> > Remove typecast in the call to kfree as it is not needed.
>
> Acked-by: Julia Lawall <julia.lawall@lip6.fr>
>
>
> > Issue found using the below coccinelle script,
> >
> > @@
> > type t1;
> > expression e;
> > @@
> >
> > -kfree((t1 *)e);
> > +kfree(e);
>
> One might consider that a slight improvement would be to declare
> expression * e; rather than expression e;, ie to ensure that e is a
> pointer.  But it's a bit of a tradeoff, because if you specify type
> information, then Coccinelle has to find the type.  If it can't find the
> type, some changes will be overlooked.  Still it could be good to try both
> approaches.  If both approaches give the same results, you can be more
> confident that everything is ok.
>

Thanks for the suggestion. I used expression *e for other sub
directories in rtl8723bs and it covered all cases once I used the
right options (-I and --recursive-includes).
Both scripts gave the same result.

> On the other hand, it would be pretty odd for an argument of kmalloc not
> to be of pointer type.
>

Yeah, I assumed and expected the script to only remove the typecast
but not to check if the parameter itself was a pointer.
Thanks for your insights.

> julia
>
> > Signed-off-by: Nachammai Karuppiah <nachukannan@gmail.com>
> > ---
> >  drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c | 10 +++++-----
> >  drivers/staging/rtl8723bs/os_dep/os_intfs.c       |  2 +-
> >  2 files changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
> > index 67d56f3..8555f52 100644
> > --- a/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
> > +++ b/drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c
> > @@ -165,7 +165,7 @@ static void rtw_spt_band_free(struct ieee80211_supported_band *spt_band)
> >                       + sizeof(struct ieee80211_channel)*RTW_2G_CHANNELS_NUM
> >                       + sizeof(struct ieee80211_rate)*RTW_G_RATES_NUM;
> >       }
> > -     kfree((u8 *)spt_band);
> > +     kfree(spt_band);
> >  }
> >
> >  static const struct ieee80211_txrx_stypes
> > @@ -1156,7 +1156,7 @@ static int cfg80211_rtw_add_key(struct wiphy *wiphy, struct net_device *ndev,
> >       }
> >
> >  addkey_end:
> > -     kfree((u8 *)param);
> > +     kfree(param);
> >
> >       return ret;
> >
> > @@ -2193,7 +2193,7 @@ static int cfg80211_rtw_connect(struct wiphy *wiphy, struct net_device *ndev,
> >                       ret = -EOPNOTSUPP ;
> >               }
> >
> > -             kfree((u8 *)pwep);
> > +             kfree(pwep);
> >
> >               if (ret < 0)
> >                       goto exit;
> > @@ -2646,7 +2646,7 @@ static int rtw_cfg80211_add_monitor_if (struct adapter *padapter, char *name, st
> >
> >  out:
> >       if (ret && mon_wdev) {
> > -             kfree((u8 *)mon_wdev);
> > +             kfree(mon_wdev);
> >               mon_wdev = NULL;
> >       }
> >
> > @@ -3502,7 +3502,7 @@ void rtw_wdev_free(struct wireless_dev *wdev)
> >
> >       wiphy_free(wdev->wiphy);
> >
> > -     kfree((u8 *)wdev);
> > +     kfree(wdev);
> >  }
> >
> >  void rtw_wdev_unregister(struct wireless_dev *wdev)
> > diff --git a/drivers/staging/rtl8723bs/os_dep/os_intfs.c b/drivers/staging/rtl8723bs/os_dep/os_intfs.c
> > index ec3a754..5044f73 100644
> > --- a/drivers/staging/rtl8723bs/os_dep/os_intfs.c
> > +++ b/drivers/staging/rtl8723bs/os_dep/os_intfs.c
> > @@ -1142,7 +1142,7 @@ void rtw_ndev_destructor(struct net_device *ndev)
> >       DBG_871X(FUNC_NDEV_FMT "\n", FUNC_NDEV_ARG(ndev));
> >
> >       if (ndev->ieee80211_ptr)
> > -             kfree((u8 *)ndev->ieee80211_ptr);
> > +             kfree(ndev->ieee80211_ptr);
> >  }
> >
> >  void rtw_dev_unload(struct adapter *padapter)
> > --
> > 2.7.4
> >
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