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

Pavel Skripkin
2021-08-21T10:35:53Z

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@gmail.com>
>> ---
>> 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@realtek.com.tw
>> #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