[PATCH v3] staging: rtl8723bs: use errno in rtw_register_tx_alive()

[Hungyu Lin]

Replace the driver-specific _SUCCESS and _FAIL return values with
0 when TX can proceed and -EAGAIN when the firmware is not ready yet.

Handle -EAGAIN explicitly in rtl8723bs_xmit_buf_handler(). The buffers
remain queued and XMIT_ALIVE remains set so cpwm_int_hdl() can wake
the TX thread for another attempt. Return _SUCCESS in this case to
keep rtw_xmit_thread() running and waiting on xmit_comp; propagating
-EAGAIN would terminate the thread.

No functional change.

Signed-off-by: Hungyu Lin <dennylin0707@xxxxxxxxx>
---
Changes in v3:
- Handle -EAGAIN explicitly in rtl8723bs_xmit_buf_handler(), as
  suggested by Greg.
- Explain why the deferred TX case returns _SUCCESS to keep the
  transmit thread running for a later retry.

Changes in v2:
- Use the standard 0/-errno return convention instead of bool, as
  suggested by Greg.
- Return -EAGAIN when the transmit path cannot proceed yet.

 drivers/staging/rtl8723bs/core/rtw_pwrctrl.c    | 13 ++++++-------
 drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c  |  9 ++++++++-
 drivers/staging/rtl8723bs/include/rtw_pwrctrl.h |  2 +-
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_pwrctrl.c b/drivers/staging/rtl8723bs/core/rtw_pwrctrl.c
index 448611ad8237..00d64b2ff89e 100644
--- a/drivers/staging/rtl8723bs/core/rtw_pwrctrl.c
+++ b/drivers/staging/rtl8723bs/core/rtw_pwrctrl.c
@@ -771,13 +771,12 @@ void rtw_unregister_task_alive(struct adapter *padapter, u32 task)
  * _SUCCESS	rtw_xmit_thread can write fifo/txcmd afterwards.
  * _FAIL		rtw_xmit_thread can not do anything.
  */
-s32 rtw_register_tx_alive(struct adapter *padapter)
+int rtw_register_tx_alive(struct adapter *padapter)
 {
-	s32 res;
+	int ret = 0;
 	struct pwrctrl_priv *pwrctrl;
 	u8 pslv;
 
-	res = _SUCCESS;
 	pwrctrl = adapter_to_pwrctl(padapter);
 	pslv = PS_STATE_S2;
 
@@ -788,7 +787,7 @@ s32 rtw_register_tx_alive(struct adapter *padapter)
 	if (pwrctrl->fw_current_in_ps_mode) {
 		if (pwrctrl->cpwm < pslv) {
 			if (pwrctrl->cpwm < PS_STATE_S2)
-				res = _FAIL;
+				ret = -EAGAIN;
 			if (pwrctrl->rpwm < pslv)
 				rtw_set_rpwm(padapter, pslv);
 		}
@@ -796,11 +795,11 @@ s32 rtw_register_tx_alive(struct adapter *padapter)
 
 	mutex_unlock(&pwrctrl->lock);
 
-	if (res == _FAIL)
+	if (ret)
 		if (pwrctrl->cpwm >= PS_STATE_S2)
-			res = _SUCCESS;
+			ret = 0;
 
-	return res;
+	return ret;
 }
 
 /*
diff --git a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
index 0441e84ea87d..47f71e3ec633 100644
--- a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
+++ b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
@@ -140,9 +140,16 @@ s32 rtl8723bs_xmit_buf_handler(struct adapter *padapter)
 		return _SUCCESS;
 
 	ret = rtw_register_tx_alive(padapter);
-	if (ret != _SUCCESS) {
+	if (ret == -EAGAIN) {
+		/*
+		 * Leave the buffers queued and XMIT_ALIVE registered so
+		 * cpwm_int_hdl() can wake this thread for another attempt.
+		 * Return success to keep the TX thread running.
+		 */
 		return _SUCCESS;
 	}
+	if (ret)
+		return _FAIL;
 
 	do {
 		queue_empty = rtl8723_dequeue_writeport(padapter);
diff --git a/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h b/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
index 49f19b6ee329..a14da6c18201 100644
--- a/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
+++ b/drivers/staging/rtl8723bs/include/rtw_pwrctrl.h
@@ -217,7 +217,7 @@ void rtw_free_pwrctrl_priv(struct adapter *adapter);
 
 s32 rtw_register_task_alive(struct adapter *adapter, u32 task);
 void rtw_unregister_task_alive(struct adapter *adapter, u32 task);
-s32 rtw_register_tx_alive(struct adapter *padapter);
+int rtw_register_tx_alive(struct adapter *padapter);
 void rtw_unregister_tx_alive(struct adapter *padapter);
 s32 rtw_register_cmd_alive(struct adapter *padapter);
 void rtw_unregister_cmd_alive(struct adapter *padapter);
-- 
2.43.0