Re: [Qemu-devel] [PATCH] Correct use of ! and &

[Markus Armbruster <armbru@redhat.com>]

"Edgar E. Iglesias" <edgar.iglesias@gmail.com> writes:

> On Sat, Aug 21, 2010 at 09:42:51AM +0000, Blue Swirl wrote:
>> Combining bitwise AND and logical NOT is suspicious.
>> 
>> Fixed by this Coccinelle script:
>> // From http://article.gmane.org/gmane.linux.kernel/646367
>> @@ expression E1,E2; @@
>> (
>>   !E1 & !E2
>> |
>> - !E1 & E2
>> + !(E1 & E2)
>> )
>> 
>> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
>> ---
>> 
>> Maybe the middle hunk should be fixed this way instead:
>> -            } else if ((rw == 1) & !matching->d) {
>> +            } else if ((rw == 1) && !matching->d) {
>> 
>> ---
>>  hw/etraxfs_eth.c    |    2 +-
>>  target-sh4/helper.c |    4 ++--
>>  2 files changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/hw/etraxfs_eth.c b/hw/etraxfs_eth.c
>> index b897c9c..ade96f1 100644
>> --- a/hw/etraxfs_eth.c
>> +++ b/hw/etraxfs_eth.c
>> @@ -464,7 +464,7 @@ static int eth_match_groupaddr(struct fs_eth *eth,
>> const unsigned char *sa)
>> 
>>  	/* First bit on the wire of a MAC address signals multicast or
>>  	   physical address.  */
>> -	if (!m_individual && !sa[0] & 1)
>> +	if (!m_individual && !(sa[0] & 1))
>>  		return 0;
>
>
> Yep, the etrax part is a bug and your patch looks OK to me.
>
> Thanks
>
> Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

Such review is exactly what we need when static analysis spots fishy
code.  Thanks!

Volunteers to look at the other two hunks?