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net: hibmcge: move dma_rmb() after dma_sync_single_for_cpu() in RX path

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The dma_rmb() barrier was placed before dma_sync_single_for_cpu(), which
is incorrect. DMA sync must complete first to make the buffer accessible
to the CPU, then the rmb barrier ensures subsequent descriptor reads
observe the latest data written by the hardware.

Reorder the operations so dma_sync_single_for_cpu() is called before
dma_rmb() to guarantee the driver reads consistent data from the DMA
buffer.

Fixes: f72e255940 ("net: hibmcge: Implement rx_poll function to receive packets")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Link: https://patch.msgid.link/20260525144525.94884-3-shaojijie@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Jijie Shao 2026-05-25 22:45:25 +08:00 committed by Paolo Abeni
parent 463a1271aa
commit b545b6ea18
1 changed files with 3 additions and 3 deletions
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6
drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.c
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@ -452,12 +452,12 @@ static bool hbg_sync_data_from_hw(struct hbg_priv *priv,
{
struct hbg_rx_desc *rx_desc;
/* make sure HW write desc complete */
dma_rmb();
dma_sync_single_for_cpu(&priv->pdev->dev, buffer->page_dma,
buffer->page_size, DMA_FROM_DEVICE);
/* make sure HW write desc complete */
dma_rmb();
rx_desc = (struct hbg_rx_desc *)buffer->page_addr;
return FIELD_GET(HBG_RX_DESC_W2_PKT_LEN_M, rx_desc->word2) != 0;
}