staging: rtl8723bs: introduce kmemdup() where applicable

Replace memory allocation followed by memcpy() with kmemdup() to simplify
the code and improve readability.

About GFP Flags:
- GFP_ATOMIC is used for allocations in atomic contexts such as
  spinlock-protected sections, tasklets, and timer handlers.
- GFP_KERNEL is used for process contexts where sleeping is allowed.

Specifically, in OnAssocReq(), GFP_ATOMIC is used because
the allocation is performed while holding a spin lock.

Signed-off-by: Minu Jin <s9430939@naver.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Link: https://patch.msgid.link/20260204131347.3515949-2-s9430939@naver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Jminu

drivers/staging/rtl8723bs/core/rtw_ap.c

@@ -114,11 +114,8 @@ static void update_BCNTIM(struct adapter *padapter)
 		dst_ie = pie + offset;
 	}
 
-	if (remainder_ielen > 0) {
-		pbackup_remainder_ie = rtw_malloc(remainder_ielen);
-		if (pbackup_remainder_ie && premainder_ie)
-			memcpy(pbackup_remainder_ie, premainder_ie, remainder_ielen);
-	}
+	if (premainder_ie && remainder_ielen)
+		pbackup_remainder_ie = kmemdup(premainder_ie, remainder_ielen, GFP_ATOMIC);
 
 	*dst_ie++ = WLAN_EID_TIM;
 
@@ -1442,11 +1439,8 @@ static void update_bcn_wps_ie(struct adapter *padapter)
 
 	remainder_ielen = ielen - wps_offset - wps_ielen;
 
-	if (remainder_ielen > 0) {
-		pbackup_remainder_ie = rtw_malloc(remainder_ielen);
-		if (pbackup_remainder_ie)
-			memcpy(pbackup_remainder_ie, premainder_ie, remainder_ielen);
-	}
+	if (premainder_ie && remainder_ielen)
+		pbackup_remainder_ie = kmemdup(premainder_ie, remainder_ielen, GFP_ATOMIC);
 
 	wps_ielen = (uint)pwps_ie_src[1];/* to get ie data len */
 	if ((wps_offset + wps_ielen + 2 + remainder_ielen) <= MAX_IE_SZ) {

drivers/staging/rtl8723bs/core/rtw_mlme.c

@@ -1326,10 +1326,9 @@ void rtw_stassoc_event_callback(struct adapter *adapter, u8 *pbuf)
 			/* report to upper layer */
 			spin_lock_bh(&psta->lock);
 			if (psta->passoc_req && psta->assoc_req_len > 0) {
-				passoc_req = rtw_zmalloc(psta->assoc_req_len);
+				passoc_req = kmemdup(psta->passoc_req, psta->assoc_req_len, GFP_ATOMIC);
 				if (passoc_req) {
 					assoc_req_len = psta->assoc_req_len;
-					memcpy(passoc_req, psta->passoc_req, assoc_req_len);
 
 					kfree(psta->passoc_req);
 					psta->passoc_req = NULL;

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c

@@ -1323,11 +1323,10 @@ unsigned int OnAssocReq(struct adapter *padapter, union recv_frame *precv_frame)
 		spin_lock_bh(&pstat->lock);
 		kfree(pstat->passoc_req);
 		pstat->assoc_req_len = 0;
-		pstat->passoc_req =  rtw_zmalloc(pkt_len);
-		if (pstat->passoc_req) {
-			memcpy(pstat->passoc_req, pframe, pkt_len);
+		pstat->passoc_req = kmemdup(pframe, pkt_len, GFP_ATOMIC);
+		if (pstat->passoc_req)
 			pstat->assoc_req_len = pkt_len;
-		}
+
 		spin_unlock_bh(&pstat->lock);
 
 		/* 3-(1) report sta add event */

drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c

@@ -159,12 +159,10 @@ static void rtl8723bs_c2h_packet_handler(struct adapter *padapter,
 	if (length == 0)
 		return;
 
-	tmp = rtw_zmalloc(length);
+	tmp = kmemdup(pbuf, length, GFP_ATOMIC);
 	if (!tmp)
 		return;
 
-	memcpy(tmp, pbuf, length);
-
 	res = rtw_c2h_packet_wk_cmd(padapter, tmp, length);
 
 	if (!res)

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c

@@ -1163,11 +1163,10 @@ static int rtw_cfg80211_set_probe_req_wpsp2pie(struct adapter *padapter, char *b
 				pmlmepriv->wps_probe_req_ie = NULL;
 			}
 
-			pmlmepriv->wps_probe_req_ie = rtw_malloc(wps_ielen);
+			pmlmepriv->wps_probe_req_ie = kmemdup(wps_ie, wps_ielen, GFP_KERNEL);
 			if (!pmlmepriv->wps_probe_req_ie)
 				return -EINVAL;
 
-			memcpy(pmlmepriv->wps_probe_req_ie, wps_ie, wps_ielen);
 			pmlmepriv->wps_probe_req_ie_len = wps_ielen;
 		}
 	}

drivers/staging/rtl8723bs/os_dep/osdep_service.c

@@ -129,11 +129,9 @@ void rtw_buf_update(u8 **buf, u32 *buf_len, u8 *src, u32 src_len)
 		goto keep_ori;
 
 	/* duplicate src */
-	dup = rtw_malloc(src_len);
-	if (dup) {
+	dup = kmemdup(src, src_len, GFP_ATOMIC);
+	if (dup)
 		dup_len = src_len;
-		memcpy(dup, src, dup_len);
-	}
 
 keep_ori:
 	ori = *buf;