Re: [PATCH RFC 1/3] staging: r8188eu: add proper rtw_read* error handling

[Pavel Skripkin]

On 8/21/21 8:55 AM, Fabio M. De Francesco wrote:
> On Friday, August 20, 2021 7:07:36 PM CEST Pavel Skripkin wrote:
> > rtw_read*() functions call usb_read* inside. These functions could fail
> > in some cases; for example: failed to receive control message. These
> > cases should be handled to prevent uninit value bugs, since usb_read*
> > functions blindly return stack variable without checking if this value
> > _actualy_ initialized.
> >
> > To achive it, all usb_read* and rtw_read*() argument list is expanded
>
> Dear Pavel,
>
> Please, achive --> achieve.
>
> > with pointer to error and added error usbctrl_vendorreq() error checking.
> > If transfer is successful error will be initialized to 0 otherwise to
> > error returned from usb_control_msg().
> >
> > To not break the build, added error checking for rtw_read*() call all
> > across the driver.
> >
> > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
> > ---
> >  drivers/staging/r8188eu/core/rtw_debug.c      |  79 +++-
> >  drivers/staging/r8188eu/core/rtw_efuse.c      |  83 +++-
> >  drivers/staging/r8188eu/core/rtw_io.c         |  18 +-
> >  drivers/staging/r8188eu/core/rtw_mp.c         |  37 +-
> >  drivers/staging/r8188eu/core/rtw_mp_ioctl.c   |  20 +-
> >  drivers/staging/r8188eu/core/rtw_pwrctrl.c    |   6 +-
> >  drivers/staging/r8188eu/core/rtw_sreset.c     |   7 +-
> >  drivers/staging/r8188eu/hal/HalPwrSeqCmd.c    |   9 +-
> >  drivers/staging/r8188eu/hal/hal_com.c         |  22 +-
> >  drivers/staging/r8188eu/hal/odm_interface.c   |  12 +-
> >  drivers/staging/r8188eu/hal/rtl8188e_cmd.c    |  37 +-
> >  drivers/staging/r8188eu/hal/rtl8188e_dm.c     |   6 +-
> >  .../staging/r8188eu/hal/rtl8188e_hal_init.c   | 198 +++++++--
> >  drivers/staging/r8188eu/hal/rtl8188e_phycfg.c |  26 +-
> >  drivers/staging/r8188eu/hal/rtl8188e_sreset.c |  20 +-
> >  drivers/staging/r8188eu/hal/rtl8188eu_led.c   |  17 +-
> >  drivers/staging/r8188eu/hal/usb_halinit.c     | 394 ++++++++++++++----
> >  drivers/staging/r8188eu/hal/usb_ops_linux.c   |  16 +-
> >  drivers/staging/r8188eu/include/rtw_io.h      |  18 +-
> >  drivers/staging/r8188eu/os_dep/ioctl_linux.c  | 168 +++++---
> >  20 files changed, 941 insertions(+), 252 deletions(-)

Hi, Fabio!


Thank you for feedback

> I agree with Philip: please, split this long patch. If I were you, I'd make
> one patch for each of the three rtw_read*() and a fourth patch for usb_read*().

Make sense. Will fix in v2.

> > --- a/drivers/staging/r8188eu/core/rtw_io.c
> > +++ b/drivers/staging/r8188eu/core/rtw_io.c
> > @@ -34,44 +34,44 @@ jackson@xxxxxxxxxxxxxx
> >  #define rtw_cpu_to_le16(val)		cpu_to_le16(val)
> >  #define rtw_cpu_to_le32(val)		cpu_to_le32(val)
>
> Not related to your patch, these macros are useless and misleading.

Sorry, I don't get it. I didn't touch these macros, it's part of diffstat.

> > -u8 _rtw_read8(struct adapter *adapter, u32 addr)
> > +u8 _rtw_read8(struct adapter *adapter, u32 addr, int *error)
> >  {
> >  	u8 r_val;
> >  	struct io_priv *pio_priv = &adapter->iopriv;
> >  	struct	intf_hdl *pintfhdl = &pio_priv->intf;
> > -	u8 (*_read8)(struct intf_hdl *pintfhdl, u32 addr);
> > +	u8 (*_read8)(struct intf_hdl *pintfhdl, u32 addr, int *error);
> >  
> >  
> >  	_read8 = pintfhdl->io_ops._read8;
> > -	r_val = _read8(pintfhdl, addr);
> > +	r_val = _read8(pintfhdl, addr, error);
> >  
> >  	return r_val;
> >  }
>
> I really don't like passing errors through arguments. Why don't you pass
> a storage location where the function save the byte read and instead use the
> return for errors? I think that this would result in a cleaner design. Furthermore,
> it is used everywhere in the kernel.
>    

Yep, this will be more cleaner, but I decided to receive some feedback 
first about the idea. If this error handling is really necessary, I will 
rework this approach :)


> > -u16 _rtw_read16(struct adapter *adapter, u32 addr)
> > +u16 _rtw_read16(struct adapter *adapter, u32 addr, int *error)
> >  {
> >  	u16 r_val;
> >  	struct io_priv *pio_priv = &adapter->iopriv;
> >  	struct	intf_hdl		*pintfhdl = &pio_priv->intf;
> > -	u16 (*_read16)(struct intf_hdl *pintfhdl, u32 addr);
> > +	u16 (*_read16)(struct intf_hdl *pintfhdl, u32 addr, int *error);
> >  
> >  	_read16 = pintfhdl->io_ops._read16;
> >  
> > -	r_val = _read16(pintfhdl, addr);
> > +	r_val = _read16(pintfhdl, addr, error);
> >  
> >  	return r_val;
> >  }
>
> Same.
>
> > -u32 _rtw_read32(struct adapter *adapter, u32 addr)
> > +u32 _rtw_read32(struct adapter *adapter, u32 addr, int *error)
> >  {
> >  	u32 r_val;
> >  	struct io_priv *pio_priv = &adapter->iopriv;
> >  	struct	intf_hdl		*pintfhdl = &pio_priv->intf;
> > -	u32	(*_read32)(struct intf_hdl *pintfhdl, u32 addr);
> > +	u32	(*_read32)(struct intf_hdl *pintfhdl, u32 addr, int *error);
> >  
> >  	_read32 = pintfhdl->io_ops._read32;
> >  
> > -	r_val = _read32(pintfhdl, addr);
> > +	r_val = _read32(pintfhdl, addr, error);
> >  
> >  	return r_val;
> >  }
>
> Same.
>
> I'm done for now: too many lines to read all at once :)



With regards,
Pavel Skripkin