Re: [PATCH rfc v0 2/9] net: dsa: qca8k: Move completion into DSA core
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2022-09-20 14:43:12
On Tue, Sep 20, 2022 at 12:18:46AM +0200, Andrew Lunn wrote:
quoted hunk ↗ jump to hunk
@@ -248,8 +248,6 @@ static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len) skb->dev = priv->mgmt_master; - reinit_completion(&mgmt_eth_data->rw_done); - /* Increment seq_num and set it in the mdio pkt */ mgmt_eth_data->seq++; qca8k_mdio_header_fill_seq_num(skb, mgmt_eth_data->seq);@@ -257,8 +255,8 @@ static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len) dev_queue_xmit(skb); - ret = wait_for_completion_timeout(&mgmt_eth_data->rw_done, - QCA8K_ETHERNET_TIMEOUT); + ret = dsa_inband_wait_for_completion(&mgmt_eth_data->inband, + QCA8K_ETHERNET_TIMEOUT); *val = mgmt_eth_data->data[0]; if (len > QCA_HDR_MGMT_DATA1_LEN)
Replacing the pattern above with this pattern:
int dsa_inband_wait_for_completion(struct dsa_inband *inband, int timeout_ms)
{
unsigned long jiffies = msecs_to_jiffies(timeout_ms);
reinit_completion(&inband->completion);
return wait_for_completion_timeout(&inband->completion, jiffies);
}
is buggy because we reinitialize the completion later than the original
code used to. We now call reinit_completion() from a code path that
races with the handler that is supposed to call dsa_inband_complete().