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

Fabio M. De Francesco
2021-08-21T05:55:41Z

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(-)

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*().

> --- 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.

> -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.

> -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 :)

Regards,

Fabio