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

[David Laight]

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.

	David

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