net: stmmac: avoid unnecessary work in stmmac_release()/stmmac_dvr_remove()

Hi,

This small series is a subset of a RFC I sent earlier. These two patches remove code that is unnecessary and/or wrong in these paths. Details in each commit.

 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 -----
 1 file changed, 5 deletions(-)

RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

While the network device is registered, it is published to userspace, and thus userspace can change its state. This means calling functions such as stmmac_stop_all_dma() and stmmac_mac_set() are racy.

Moreover, unregister_netdev() will unpublish the network device, and then if appropriate call the .ndo_stop() method, which is stmmac_release(). This will first call phylink_stop() which will synchronously take the link down, resulting in stmmac_mac_link_down() and stmmac_mac_set(, false) being called.

stmmac_release() will also call stmmac_stop_all_dma().

Consequently, neither of these two functions need to called prior to unregister_netdev() as that will safely call paths that will result in this work being done if necessary.

Remove these redundant racy calls.

---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 --
 1 file changed, 2 deletions(-)

index fa1d7d3a2f43..c2ee6c0af3fd 100644
@@ -7768,8 +7768,6 @@ void stmmac_dvr_remove(struct device *dev)
 
 	pm_runtime_get_sync(dev);
 
-	stmmac_stop_all_dma(priv);
-	stmmac_mac_set(priv, priv->ioaddr, false);
 	unregister_netdev(ndev);
 
 #ifdef CONFIG_DEBUG_FS

2.30.2

stmmac_release() calls phylink_stop() and then goes on to call stmmac_mac_set(, false). However, phylink_stop() will call stmmac_mac_link_down() before returning, which will do this work. Remove this unnecessary call.

---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ---
 1 file changed, 3 deletions(-)

index c2ee6c0af3fd..839ecebf5f5f 100644
@@ -4129,9 +4129,6 @@ static int stmmac_release(struct net_device *dev)
 	/* Release and free the Rx/Tx resources */
 	free_dma_desc_resources(priv, &priv->dma_conf);
 
-	/* Disable the MAC Rx/Tx */
-	stmmac_mac_set(priv, priv->ioaddr, false);
-
 	/* Powerdown Serdes if there is */
 	if (priv->plat->serdes_powerdown)
 		priv->plat->serdes_powerdown(dev, priv->plat->bsp_priv);

2.30.2

Hi Jakub,

Why is this series showing in patchwork, but not being subjected to any nipabot tests?

There's also "net: phylink: expand on .pcs_config() method documentation" which isn't being subjected to nipabot tests.

Thanks.

RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

We had an outage in the nipa infra that caused no test running for a while. At least it entered later CI runs.

Cheers,

Paolo