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realtek: fix locking bug in rtl838x_hw_receive() 

A Locking bug in the packet receive path was introduced with PR
#4973. The following patch prevents the driver from locking
after a few minutes with an endless flow of

[ 1434.185085] rtl838x-eth 1b00a300.ethernet eth0: Ring contention: r: 0, last a28000f4, cur a28000f8
[ 1434.208971] rtl838x-eth 1b00a300.ethernet eth0: Ring contention: r: 0, last a28000f4, cur a28000fc
[ 1434.794800] rtl838x-eth 1b00a300.ethernet eth0: Ring contention: r: 0, last a28000f4, cur a28000fc
[ 1435.049187] rtl838x-eth 1b00a300.ethernet eth0: Ring contention: r: 0, last a28000f4, cur a28000fc

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
This commit is contained in:
Birger Koblitz 2022-02-18 12:01:53 +01:00 committed by Daniel Golle
parent e9e61d76fd
commit 4d8020072e
1 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c
View File

@ -1254,8 +1254,9 @@ static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)
bool dsa = netdev_uses_dsa(dev);
struct dsa_tag tag;
last = (u32 *)KSEG1ADDR(sw_r32(priv->r->dma_if_rx_cur + r * 4));
pr_debug("---------------------------------------------------------- RX - %d\n", r);
spin_lock_irqsave(&priv->lock, flags);
last = (u32 *)KSEG1ADDR(sw_r32(priv->r->dma_if_rx_cur + r * 4));
do {
if ((ring->rx_r[r][ring->c_rx[r]] & 0x1)) {
@ -1329,7 +1330,6 @@ static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)
}
/* Reset header structure */
spin_lock_irqsave(&priv->lock, flags);
memset(h, 0, sizeof(struct p_hdr));
h->buf = data;
h->size = RING_BUFFER;
@ -1338,12 +1338,13 @@ static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)
| (ring->c_rx[r] == (priv->rxringlen - 1) ? WRAP : 0x1);
ring->c_rx[r] = (ring->c_rx[r] + 1) % priv->rxringlen;
last = (u32 *)KSEG1ADDR(sw_r32(priv->r->dma_if_rx_cur + r * 4));
spin_unlock_irqrestore(&priv->lock, flags);
} while (&ring->rx_r[r][ring->c_rx[r]] != last && work_done < budget);
// Update counters
priv->r->update_cntr(r, 0);
spin_unlock_irqrestore(&priv->lock, flags);
return work_done;
}