[PATCH v3] staging: rtl8723bs: Use % 4096u instead of & 0xfff

Abraham Samuel Adekunle
2025-04-07T00:27:57Z

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
explicit and easier to understand. It clearly signals that the sequence
number cycles though a range of 4096 values.

The use of `4096u` also guarantees that the modulo operation is performed
with unsigned arithmetic, preventing potential issues with signed types.

Suggested-by: Andy Shevchenko <andy@kernel.org>
David Laight <david.laight.linux@gmail.com>

Signed-off-by: Abraham Samuel Adekunle <abrahamadekunle50@gmail.com>
---
Changes in v2:
- Changed the commit message to a more descriptive message which
makes it clear why the patch does the change.
- Changed the subject title to include `4096u` to show that an unsigned
module is used.
Changes in v1:
- Added more patch recipients.

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 297c93d65315..f534bf2448c3 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);
@@ -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;

pattrib->ampdu_en = true;/* AGG EN */
} else {
- psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (pattrib->seqnum+1)&0xfff;
+ psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (pattrib->seqnum+1)&4096u;
pattrib->ampdu_en = true;/* AGG EN */
}
}
--
2.34.1