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SubjectRe: [PATCH 5/5]bluetooth:hci_bcsp Fix operation on 'bcsp->msgq_txseq' may be undefined
On 06/28/2010 05:52 AM, David Howells wrote:
> Justin P. Mattock<justinmattock@gmail.com> wrote:
>
>> - BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
>> - bcsp->msgq_txseq = ++(bcsp->msgq_txseq)& 0x07;
>> + BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq | ret);
>> + ret = ++(bcsp->msgq_txseq)& 0x07;
>
> I don't know what you're trying to do here, but you seem to be trying to send
> the computed value back in time.
>

I was under the impression that hdr[0] |= 0x80 + bcsp->msgq_txseq;
is computing a value for BT_DBG then ret = ++(bcsp->msgq_txseq)& 0x07
computes a value as well i.e.
BT_DBG("Sending packet with seqno %u", hdr[0] | ret);
> The problem is that the compiler is confused about why a '++' operator makes
> any sense here. It doesn't. It should be a '+ 1' instead. I think what you
> want is:
>
> - bcsp->msgq_txseq = ++(bcsp->msgq_txseq)& 0x07;
> + bcsp->msgq_txseq = (bcsp->msgq_txseq + 1)& 0x07;
>
> David
>

yeah I did play around with the ++ and noticed the compiler would be
satisfied if the ++ was not there, but didn't think to just add a + 1

Justin P. Mattock


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