2020-09-17 05:10:15

by Wong, Vee Khee

Subject: [PATCH net-next] net: stmmac: introduce rtnl_lock|unlock() on configuring real_num_rx|tx_queues

From: "Tan, Tee Min" <[email protected]>

For driver open(), rtnl_lock is acquired by network stack but not in the
resume(). Therefore, we introduce lock_acquired boolean to control when
to use rtnl_lock|unlock() within stmmac_hw_setup().

Fixes: 686cff3d7022 ("net: stmmac: Fix incorrect location to set real_num_rx|tx_queues")

Signed-off-by: Tan, Tee Min <[email protected]>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index df2c74bbfcff..22e6a3defa78 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2607,7 +2607,8 @@ static void stmmac_safety_feat_configuration(struct stmmac_priv *priv)
* 0 on success and an appropriate (-)ve integer as defined in errno.h
* file on failure.
*/
-static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
+static int stmmac_hw_setup(struct net_device *dev, bool init_ptp,
+ bool lock_acquired)
{
struct stmmac_priv *priv = netdev_priv(dev);
u32 rx_cnt = priv->plat->rx_queues_to_use;
@@ -2715,9 +2716,15 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
}

/* Configure real RX and TX queues */
+ if (!lock_acquired)
+ rtnl_lock();
+
netif_set_real_num_rx_queues(dev, priv->plat->rx_queues_to_use);
netif_set_real_num_tx_queues(dev, priv->plat->tx_queues_to_use);

+ if (!lock_acquired)
+ rtnl_unlock();
+
/* Start the ball rolling... */
stmmac_start_all_dma(priv);

@@ -2804,7 +2811,7 @@ static int stmmac_open(struct net_device *dev)
goto init_error;
}

- ret = stmmac_hw_setup(dev, true);
+ ret = stmmac_hw_setup(dev, true, true);
if (ret < 0) {
netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
goto init_error;
@@ -5238,7 +5245,7 @@ int stmmac_resume(struct device *dev)

stmmac_clear_descriptors(priv);

- stmmac_hw_setup(ndev, false);
+ stmmac_hw_setup(ndev, false, false);
stmmac_init_coalesce(priv);
stmmac_set_rx_mode(ndev);

--
2.17.0

2020-09-17 07:08:50

by Leon Romanovsky

Subject: Re: [PATCH net-next] net: stmmac: introduce rtnl_lock|unlock() on configuring real_num_rx|tx_queues

On Thu, Sep 17, 2020 at 01:02:15PM +0800, Wong Vee Khee wrote:
> From: "Tan, Tee Min" <[email protected]>
>
> For driver open(), rtnl_lock is acquired by network stack but not in the
> resume(). Therefore, we introduce lock_acquired boolean to control when
> to use rtnl_lock|unlock() within stmmac_hw_setup().

Doesn't really make sense, if function needs to have lock acquired, the
caller is supposed to take it and function should have proper lockdep
annotation inside and not this conditional lock/unlock.

Thanks

>
> Fixes: 686cff3d7022 ("net: stmmac: Fix incorrect location to set real_num_rx|tx_queues")
>

Extra line.

> Signed-off-by: Tan, Tee Min <[email protected]>
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index df2c74bbfcff..22e6a3defa78 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2607,7 +2607,8 @@ static void stmmac_safety_feat_configuration(struct stmmac_priv *priv)
> * 0 on success and an appropriate (-)ve integer as defined in errno.h
> * file on failure.
> */
> -static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
> +static int stmmac_hw_setup(struct net_device *dev, bool init_ptp,
> + bool lock_acquired)
> {
> struct stmmac_priv *priv = netdev_priv(dev);
> u32 rx_cnt = priv->plat->rx_queues_to_use;
> @@ -2715,9 +2716,15 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
> }
>
> /* Configure real RX and TX queues */
> + if (!lock_acquired)
> + rtnl_lock();
> +
> netif_set_real_num_rx_queues(dev, priv->plat->rx_queues_to_use);
> netif_set_real_num_tx_queues(dev, priv->plat->tx_queues_to_use);
>
> + if (!lock_acquired)
> + rtnl_unlock();
> +
> /* Start the ball rolling... */
> stmmac_start_all_dma(priv);
>
> @@ -2804,7 +2811,7 @@ static int stmmac_open(struct net_device *dev)
> goto init_error;
> }
>
> - ret = stmmac_hw_setup(dev, true);
> + ret = stmmac_hw_setup(dev, true, true);
> if (ret < 0) {
> netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
> goto init_error;
> @@ -5238,7 +5245,7 @@ int stmmac_resume(struct device *dev)
>
> stmmac_clear_descriptors(priv);
>
> - stmmac_hw_setup(ndev, false);
> + stmmac_hw_setup(ndev, false, false);
> stmmac_init_coalesce(priv);
> stmmac_set_rx_mode(ndev);
>
> --
> 2.17.0
>