netdev - [PATCH v2 net-next] net: ethernet: mtk_wed: get rid of queue lock for rx queue

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Message-Id: <36ec3b729542ea60898471d890796f745479ba32.1673342990.git.lorenzo@kernel.org>
Date:   Tue, 10 Jan 2023 10:31:26 +0100
From:   Lorenzo Bianconi <lorenzo@...nel.org>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, lorenzo.bianconi@...hat.com, nbd@....name,
        john@...ozen.org, sean.wang@...iatek.com, Mark-MC.Lee@...iatek.com,
        sujuan.chen@...iatek.com, daniel@...rotopia.org,
        alexanderduyck@...com
Subject: [PATCH v2 net-next] net: ethernet: mtk_wed: get rid of queue lock for rx queue

Queue spinlock is currently held in mtk_wed_wo_queue_rx_clean and
mtk_wed_wo_queue_refill routines for MTK Wireless Ethernet Dispatcher
MCU rx queue. mtk_wed_wo_queue_refill() is running during initialization
and in rx tasklet while mtk_wed_wo_queue_rx_clean() is running in
mtk_wed_wo_hw_deinit() during hw de-init phase after rx tasklet has been
disabled. Since mtk_wed_wo_queue_rx_clean and mtk_wed_wo_queue_refill
routines can't run concurrently get rid of spinlock for mcu rx queue.

Reviewed-by: Alexander Duyck <alexanderduyck@...com>
Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
---
Changes since v1:
- improve commit message
---
 drivers/net/ethernet/mediatek/mtk_wed_wo.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_wed_wo.c b/drivers/net/ethernet/mediatek/mtk_wed_wo.c
index a0a39643caf7..d32b86499896 100644
--- a/drivers/net/ethernet/mediatek/mtk_wed_wo.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed_wo.c
@@ -138,7 +138,6 @@ mtk_wed_wo_queue_refill(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q,
 	enum dma_data_direction dir = rx ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 	int n_buf = 0;
 
-	spin_lock_bh(&q->lock);
 	while (q->queued < q->n_desc) {
 		struct mtk_wed_wo_queue_entry *entry;
 		dma_addr_t addr;
@@ -172,7 +171,6 @@ mtk_wed_wo_queue_refill(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q,
 		q->queued++;
 		n_buf++;
 	}
-	spin_unlock_bh(&q->lock);
 
 	return n_buf;
 }
@@ -316,7 +314,6 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q)
 {
 	struct page *page;
 
-	spin_lock_bh(&q->lock);
 	for (;;) {
 		void *buf = mtk_wed_wo_dequeue(wo, q, NULL, true);
 
@@ -325,7 +322,6 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q)
 
 		skb_free_frag(buf);
 	}
-	spin_unlock_bh(&q->lock);
 
 	if (!q->cache.va)
 		return;
-- 
2.39.0