Messages in this thread Patch in this message |  | | From | Abraham Samuel Adekunle <> | | Subject | [PATCH v9 2/2] staging: rtl8723bs: Use % 4096 instead of & 0xfff | | Date | Wed, 9 Apr 2025 09:12:55 +0000 |
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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 `% 4096u` makes the wrap-around logic explicit and easier to understand. It clearly signals that the sequence number cycles through a range of 4096 values. It also makes the code robust against potential changes of the 4096 upper limit, especially when it becomes a non power-of-2 value while the AND(&) works solely for power-of-2 values.
The use of `% 4096u` also guarantees that the modulo operation is performed with unsigned arithmetic, preventing potential issues with the signed types.
Suggested-by: Andy Shevchenko <andy@kernel.org> Suggested-by: David Laight <david.laight.linux@gmail.com> Signed-off-by: Abraham Samuel Adekunle <abrahamadekunle50@gmail.com> Reviewed-by: Andy Shevchenko <andy@kernel.org> --- drivers/staging/rtl8723bs/core/rtw_xmit.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/rtl8723bs/core/rtw_xmit.c b/drivers/staging/rtl8723bs/core/rtw_xmit.c index 5def2467f42b..76f25ab6a779 100644 --- a/drivers/staging/rtl8723bs/core/rtw_xmit.c +++ b/drivers/staging/rtl8723bs/core/rtw_xmit.c @@ -943,7 +943,7 @@ s32 rtw_make_wlanhdr(struct adapter *padapter, u8 *hdr, struct pkt_attrib *pattr if (psta) { psta->sta_xmitpriv.txseq_tid[pattrib->priority]++; - psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 0xFFF; + psta->sta_xmitpriv.txseq_tid[pattrib->priority] %= 4096u; pattrib->seqnum = psta->sta_xmitpriv.txseq_tid[pattrib->priority]; SetSeqNum(hdr, pattrib->seqnum); @@ -964,12 +964,12 @@ s32 rtw_make_wlanhdr(struct adapter *padapter, u8 *hdr, struct pkt_attrib *pattr 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; + (tx_seq + 1) % 4096u; pattrib->ampdu_en = true;/* AGG EN */ } else { psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = - (pattrib->seqnum + 1) & 0xfff; + (pattrib->seqnum + 1) % 4096u; pattrib->ampdu_en = true;/* AGG EN */ } -- 2.34.1
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