target/linux/generic/backport-5.15/729-16-v6.3-net-ethernet-mtk_wed-get-rid-of-queue-lock-for-rx-qu.patch

   1 From: Lorenzo Bianconi <lorenzo@kernel.org>
   2 Date: Tue, 10 Jan 2023 10:31:26 +0100
   3 Subject: [PATCH] net: ethernet: mtk_wed: get rid of queue lock for rx queue
   4
   5 Queue spinlock is currently held in mtk_wed_wo_queue_rx_clean and
   6 mtk_wed_wo_queue_refill routines for MTK Wireless Ethernet Dispatcher
   7 MCU rx queue. mtk_wed_wo_queue_refill() is running during initialization
   8 and in rx tasklet while mtk_wed_wo_queue_rx_clean() is running in
   9 mtk_wed_wo_hw_deinit() during hw de-init phase after rx tasklet has been
  10 disabled. Since mtk_wed_wo_queue_rx_clean and mtk_wed_wo_queue_refill
  11 routines can't run concurrently get rid of spinlock for mcu rx queue.
  12
  13 Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
  14 Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
  15 Link: https://lore.kernel.org/r/36ec3b729542ea60898471d890796f745479ba32.1673342990.git.lorenzo@kernel.org
  16 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  17 ---
  18
  19 --- a/drivers/net/ethernet/mediatek/mtk_wed_wo.c
  20 +++ b/drivers/net/ethernet/mediatek/mtk_wed_wo.c
  21 @@ -138,7 +138,6 @@ mtk_wed_wo_queue_refill(struct mtk_wed_w
  22         enum dma_data_direction dir = rx ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
  23         int n_buf = 0;
  24
  25 -       spin_lock_bh(&q->lock);
  26         while (q->queued < q->n_desc) {
  27                 struct mtk_wed_wo_queue_entry *entry;
  28                 dma_addr_t addr;
  29 @@ -172,7 +171,6 @@ mtk_wed_wo_queue_refill(struct mtk_wed_w
  30                 q->queued++;
  31                 n_buf++;
  32         }
  33 -       spin_unlock_bh(&q->lock);
  34
  35         return n_buf;
  36  }
  37 @@ -316,7 +314,6 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed
  38  {
  39         struct page *page;
  40
  41 -       spin_lock_bh(&q->lock);
  42         for (;;) {
  43                 void *buf = mtk_wed_wo_dequeue(wo, q, NULL, true);
  44
  45 @@ -325,7 +322,6 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed
  46
  47                 skb_free_frag(buf);
  48         }
  49 -       spin_unlock_bh(&q->lock);
  50
  51         if (!q->cache.va)
  52                 return;