linux-kernel - [PATCH 3/3] wifi: ath11k: use plain accesses for monitor descriptor

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Message-ID: <20250526114803.2122-4-johan+linaro@kernel.org>
Date: Mon, 26 May 2025 13:48:03 +0200
From: Johan Hovold <johan+linaro@...nel.org>
To: Jeff Johnson <jjohnson@...nel.org>
Cc: Miaoqing Pan <quic_miaoqing@...cinc.com>,
	linux-wireless@...r.kernel.org,
	ath11k@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Johan Hovold <johan+linaro@...nel.org>
Subject: [PATCH 3/3] wifi: ath11k: use plain accesses for monitor descriptor

The read memory barrier added by commit ab52e3e44fe9 ("wifi: ath11k: fix
rx completion meta data corruption") is enough to guarantee ordering
also for plain descriptor accesses so drop the unnecessary READ_ONCE().

Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 drivers/net/wireless/ath/ath11k/dp_rx.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
index dfe2d889c20f..37deb78044c8 100644
--- a/drivers/net/wireless/ath/ath11k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
@@ -2637,7 +2637,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 	struct ath11k *ar;
 	struct hal_reo_dest_ring *desc;
 	enum hal_reo_dest_ring_push_reason push_reason;
-	u32 cookie, info0, rx_msdu_info0, rx_mpdu_info0;
+	u32 cookie;
 	int i;
 
 	for (i = 0; i < MAX_RADIOS; i++)
@@ -2657,7 +2657,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 	      (struct hal_reo_dest_ring *)ath11k_hal_srng_dst_get_next_entry(ab,
 									     srng))) {
 		cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
-				   READ_ONCE(desc->buf_addr_info.info1));
+				   desc->buf_addr_info.info1);
 		buf_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_BUF_ID,
 				   cookie);
 		mac_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_PDEV_ID, cookie);
@@ -2686,9 +2686,8 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 
 		num_buffs_reaped[mac_id]++;
 
-		info0 = READ_ONCE(desc->info0);
 		push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON,
-					info0);
+					desc->info0);
 		if (unlikely(push_reason !=
 			     HAL_REO_DEST_RING_PUSH_REASON_ROUTING_INSTRUCTION)) {
 			dev_kfree_skb_any(msdu);
@@ -2696,21 +2695,18 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 			continue;
 		}
 
-		rx_msdu_info0 = READ_ONCE(desc->rx_msdu_info.info0);
-		rx_mpdu_info0 = READ_ONCE(desc->rx_mpdu_info.info0);
-
-		rxcb->is_first_msdu = !!(rx_msdu_info0 &
+		rxcb->is_first_msdu = !!(desc->rx_msdu_info.info0 &
 					 RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
-		rxcb->is_last_msdu = !!(rx_msdu_info0 &
+		rxcb->is_last_msdu = !!(desc->rx_msdu_info.info0 &
 					RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
-		rxcb->is_continuation = !!(rx_msdu_info0 &
+		rxcb->is_continuation = !!(desc->rx_msdu_info.info0 &
 					   RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
 		rxcb->peer_id = FIELD_GET(RX_MPDU_DESC_META_DATA_PEER_ID,
-					  READ_ONCE(desc->rx_mpdu_info.meta_data));
+					  desc->rx_mpdu_info.meta_data);
 		rxcb->seq_no = FIELD_GET(RX_MPDU_DESC_INFO0_SEQ_NUM,
-					 rx_mpdu_info0);
+					 desc->rx_mpdu_info.info0);
 		rxcb->tid = FIELD_GET(HAL_REO_DEST_RING_INFO0_RX_QUEUE_NUM,
-				      info0);
+				      desc->info0);
 
 		rxcb->mac_id = mac_id;
 		__skb_queue_tail(&msdu_list[mac_id], msdu);
-- 
2.49.0