Re: [PATCH v3 2/5] staging: r8188eu: cast to restricted __be32

[Dan Carpenter]

On Wed, Aug 25, 2021 at 10:21:23AM +0000, David Laight wrote:
> From: Dan Carpenter
> > Sent: 25 August 2021 10:19
> > 
> > On Wed, Aug 25, 2021 at 09:13:44AM +0000, David Laight wrote:
> > > From: Larry Finger
> > > > Sent: 23 August 2021 15:24
> > > >
> > > > On 8/23/21 3:44 AM, Aakash Hemadri wrote:
> > > > > On 21/08/21 09:48PM, Aakash Hemadri wrote:
> > > > >> Fix sparse warning:
> > > > >>> rtw_br_ext.c:836:54: warning: cast to restricted __be32
> > > > >>
> > > > >> dhpch->cookie is be32, change it's type.
> > > ...
> > > > >> diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c
> > b/drivers/staging/r8188eu/core/rtw_br_ext.c
> > > > >> index f6d1f6029ec3..f65d94bfa286 100644
> > > > >> --- a/drivers/staging/r8188eu/core/rtw_br_ext.c
> > > > >> +++ b/drivers/staging/r8188eu/core/rtw_br_ext.c
> > > ...
> > > > >> @@ -671,7 +671,7 @@ void dhcp_flag_bcast(struct adapter *priv, struct sk_buff *skb)
> > > > >>   				    (udph->dest == __constant_htons(SERVER_PORT))) { /*  DHCP request */
> > > > >>   					struct dhcpMessage *dhcph =
> > > > >>   						(struct dhcpMessage *)((size_t)udph + sizeof(struct
> > udphdr));
> > >
> > > This assignment looks dubious at best - WTF is (size_t) for?
> > > I don't seem to have a source tree with this driver in it (probably only in 'next'?).
> > > I suspect it should be:
> > > 	struct dhcp_message *dhcph = (void *)(udph + 1);
> > 
> > Those are equivalent.  Either way works.
> 
> size_t isn't guaranteed to be large enough to hold a pointer.

It is on every system that Linux is ever going to build on.

regards,
dan carpenter