Re: [PATCH v1] staging: r8188eu: an incorrect return value made the function always return fail

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jun 20, 2022 at 04:54:13PM +0800, Kate Hsuan wrote:
> Since _SUCCESS (1) and _FAIL (0) are used to indicate the status of the
> functions. The previous commit 8ae7bf782eacad803f752c83a183393b0a67127b

In the future, please reference commit ids as the documentation asks, as
it's a much nicer way to understand things.  Also this commit id is not
in Linus's tree or any tree that I can see, where did it come from?

> fixed and prevented dereferencing a NULL pointer through checking the
> return pointer. The NULL pointer check work properly but the return
> values (-ENOMEM on fail and 0 on success). This work fixed the return
> values to make sure the caller function will return the correct status.
> 
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2097526
> Signed-off-by: Kate Hsuan <hpa@redhat.com>
> ---
>  drivers/staging/r8188eu/core/rtw_xmit.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index f4e9f6102539..2f8720db21d9 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -180,10 +180,8 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
>  	pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
>  
>  	res = rtw_alloc_hwxmits(padapter);
> -	if (res) {
> -		res = _FAIL;
> +	if (res == _FAIL)
>  		goto exit;
> -	}
>  
>  	rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
>  
> @@ -1510,7 +1508,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
>  
>  	pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
>  	if (!pxmitpriv->hwxmits)
> -		return -ENOMEM;
> +		return _FAIL;

No, please let's fix up the callers to properly detect normal kernel
error values and get rid of all of the crazy _FAIL and _SUCCESS values
in this driver.

>  
>  	hwxmits = pxmitpriv->hwxmits;
>  
> @@ -1528,7 +1526,7 @@ int rtw_alloc_hwxmits(struct adapter *padapter)
>  	} else {
>  	}
>  
> -	return 0;
> +	return _SUCCESS;

Same here, fix up the callers if they are checking this incorrectly.

thanks,

greg k-h