Re: [PATCH] staging: r8188eu: Fix different base types in assignments and parameters

Fabio M. De Francesco
2021-08-02T14:26:40Z

On Monday, August 2, 2021 4:05:05 PM CEST Dan Carpenter wrote:
> On Fri, Jul 30, 2021 at 08:14:52PM +0200, Fabio M. De Francesco wrote:
> > Fix sparse warnings of different base types in assignments
> > and in passing function parameters.
>
> This patch fixes some endian bugs but it's not mentioned at all in the
> commit message. Did you send to the correct patch?
>

Too late to change the commit message: Greg K-H has already taken this patch
as-is (please see commit 56febcc2595e).

> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> > ---
> >
> > drivers/staging/r8188eu/core/rtw_br_ext.c | 46 ++++++++++++++++++-----
> > 1 file changed, 36 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c
> > b/drivers/staging/r8188eu/core/rtw_br_ext.c index
e00302137a60..31ca2e548555 100644
> >
> > [...]
> >
> > static inline void __nat25_generate_ipx_network_addr_with_node(unsigned
char
> > *networkAddr,>
> > - unsigned int *ipxNetAddr,
unsigned char *ipxNodeAddr)
> > + __be32 *ipxNetAddr, unsigned char
*ipxNodeAddr)
> >
> > {
> >
> > + union {
> > + unsigned int f0;
> > + unsigned char f1[IPX_NODE_LEN];
>
> What is going on here?? Why is f1 six bytes?
>

Please look at the third parameter of the latest memcpy() in this function.

> > + } addr;
> > +
> >
> > memset(networkAddr, 0, MAX_NETWORK_ADDR_LEN);
> >
> > networkAddr[0] = NAT25_IPX;
> >
> > - memcpy(networkAddr+1, (unsigned char *)ipxNetAddr, 4);
> > + addr.f0 = be32_to_cpu(*ipxNetAddr);
> > + memcpy(networkAddr+1, addr.f1, 4);
>
> What's the point of a union? memcpy() doesn't care about endian
> anotations.
>
> > memcpy(networkAddr+5, ipxNodeAddr, 6);
^^^^^

I'm talking about this memcpy().

> > }
> >
> > static inline void __nat25_generate_ipx_network_addr_with_socket(unsigned
char
> > *networkAddr,>
> > - unsigned int *ipxNetAddr,
unsigned short *ipxSocketAddr)
> > + __be32 *ipxNetAddr, __be16
*ipxSocketAddr)
> >
> > {
> >
> > + union {
> > + unsigned int f0;
> > + unsigned char f1[4];
> > + } addr;
> > +
> >
> > memset(networkAddr, 0, MAX_NETWORK_ADDR_LEN);
> >
> > networkAddr[0] = NAT25_IPX;
> >
> > - memcpy(networkAddr+1, (unsigned char *)ipxNetAddr, 4);
> > - memcpy(networkAddr+5, (unsigned char *)ipxSocketAddr, 2);
> > + addr.f0 = be32_to_cpu(*ipxNetAddr);
> > + memcpy(networkAddr+1, addr.f1, 4);
> > + addr.f0 ^= addr.f0;
>
> What on earth????

I can't see any problem in xor(ing) a field with itself. Perhaps I read too
much Assembly code :-) . However, am I missing something?

> > + addr.f0 = be16_to_cpu(*ipxSocketAddr);
>
> I'm so puzzled.
>
> > + memcpy(networkAddr+5, addr.f1, 2);
>
> This patch is really weird so I'm done reviewing it.

I'm sorry that you don't like this patch, but Greg already had the last word
on it.

> regards,
> dan carpenter

Regards,

Fabio