On Thursday, August 19, 2021 7:20:44 PM CEST Greg Kroah-Hartman wrote:

On Thu, Aug 19, 2021 at 01:47:56PM +0530, Aakash Hemadri wrote:

quoted

Fix sparse warning:

quoted

rtw_br_ext.c:839:70: warning: restricted __be16 degrades to integer
rtw_br_ext.c:845:70: warning: invalid assignment: |=
rtw_br_ext.c:845:70:    left side has type unsigned short
rtw_br_ext.c:845:70:    right side has type restricted __be16

dhcp->flag is u16, remove htons() as __be16 degrades.

Um, are you sure?

quoted

Signed-off-by: Aakash Hemadri <redacted>
---
 drivers/staging/r8188eu/core/rtw_br_ext.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
index d4acf02ca64f..14b2935cab98 100644
--- a/drivers/staging/r8188eu/core/rtw_br_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_br_ext.c

@@ -674,13 +674,13 @@ void dhcp_flag_bcast(struct adapter *priv, struct sk_buff *skb)
 					u32 cookie = dhcph->cookie;
 
 					if (cookie == DHCP_MAGIC) { /*  match magic word */
-						if (!(dhcph->flags & htons(BROADCAST_FLAG))) {
+						if (!(dhcph->flags & BROADCAST_FLAG)) {

So you now just ignore the fact that the code used to properly check
BROADCAST_FLAG being in big endian mode, and now you assume it is native
endian?

Why is this ok?  Did you test this?

thanks,

greg k-h

Aakash,

Building on the objections you had from Greg I suggest that, before attempting 
anew to address problems like these, you get a better understanding of the topics of 
native and network endianness and of the API that (conditionally) swap bytes 
in a variable between little endian and big endian representation.

To start with, please note that the following code leads to tests for "v.vub[0] == 0xDD" 
which is true on little endian architectures while "v.vub[0] == 0xAA" is true on big 
endian ones...

union {
        u32 vud;
        u8 vub[4];
} v;

v.vud = 0xAABBCCDD;

Also note that API like cpu_to_be32(), htonl(), be32_to_cpu(), ntohl, and the likes are 
used to (conditionally) swap bytes (i.e., change the arrangement of the bytes in a 
multi-bytes variable).

Casts have very different purposes and usage patterns and, above all, they cannot 
magically change the endianness of a variable.

Regards,

Fabio