Re: [PATCH 5/5]bluetooth:hci_bcsp Fix operation on 'bcsp->msgq_txseq'may be undefined

From: Justin P. Mattock
Date: Mon Jun 28 2010 - 13:56:00 EST

On 06/28/2010 05:52 AM, David Howells wrote:
Justin P. Mattock<justinmattock@xxxxxxxxx> 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;


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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