[PATCH v9 2/2] staging: rtl8723bs: Use % 4096 instead of & 0xfff

[Abraham Samuel Adekunle]

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@xxxxxxxxxx>
Suggested-by: David Laight <david.laight.linux@xxxxxxxxx>
Signed-off-by: Abraham Samuel Adekunle <abrahamadekunle50@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy@xxxxxxxxxx>
---
 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