Re: [PATCH v4] staging: rtl8723bs: Use % 4096u instead of & 0xfff

Greg KH
2025-04-07T06:55:00Z

On Mon, Apr 07, 2025 at 08:36:35AM +0200, Greg KH wrote:
> On Mon, Apr 07, 2025 at 06:30:50AM +0000, Abraham Samuel Adekunle wrote:
> > The sequence number is constrained to a range of [0, 4095], which
> > is a total of 4096 values. The bitmask operation using `0xfff` is
> > used to perform this wrap-around. While this is functionally correct,
> > it obscures the intended semantic of a 4096-based wrap.
> >
> > Using a modulo operation with `4096u` makes the wrap-around logic
>
> <snip>
>
> > - psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 0xFFF;
> > + psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 4096u;
>
> I do not see a modulo operation here, only another & operation.
>
> > pattrib->seqnum = psta->sta_xmitpriv.txseq_tid[pattrib->priority];
> >
> > SetSeqNum(hdr, pattrib->seqnum);
> > @@ -963,11 +963,11 @@ s32 rtw_make_wlanhdr(struct adapter *padapter, u8 *hdr, struct pkt_attrib *pattr
> > if (SN_LESS(pattrib->seqnum, tx_seq)) {
> > pattrib->ampdu_en = false;/* AGG BK */
> > } else if (SN_EQUAL(pattrib->seqnum, tx_seq)) {
> > - psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (tx_seq+1)&0xfff;
> > + psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (tx_seq+1)&4096u;
>
> This also looks odd, nothing is being "AND" here, it's an address value
> being set (and an odd one at that, but that's another issue...)

Sorry, no, I was wrong, it is being & here, but not %. My fault,
the lack of spaces here threw me.

thanks,

greg k-h