ptp_clock: future-proofing drivers against PTP subsystem becoming optional

Drivers must be ready to accept NULL from ptp_clock_register() if the
PTP clock subsystem is configured out.

This patch documents that and ensures that all drivers cope well
with a NULL return.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Eugenia Emantayev <eugenia@mellanox.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/intel/e1000e/ptp.c b/drivers/net/ethernet/intel/e1000e/ptp.c
index 2e1b17a..ad03763 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/ptp.c
+++ b/drivers/net/ethernet/intel/e1000e/ptp.c
@@ -334,7 +334,7 @@ void e1000e_ptp_init(struct e1000_adapter *adapter)
        if (IS_ERR(adapter->ptp_clock)) {
                adapter->ptp_clock = NULL;
                e_err("ptp_clock_register failed\n");
-       } else {
+       } else if (adapter->ptp_clock) {
                e_info("registered PHC clock\n");
        }
 }

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
index ed39cba..f1fecea 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
@@ -669,7 +669,7 @@ void i40e_ptp_init(struct i40e_pf *pf)
                pf->ptp_clock = NULL;
                dev_err(&pf->pdev->dev, "%s: ptp_clock_register failed\n",
                        __func__);
-       } else {
+       } else if (pf->ptp_clock) {
                struct timespec64 ts;
                u32 regval;
 

diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 66dfa20..1dd14e1 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -1159,7 +1159,7 @@ void igb_ptp_init(struct igb_adapter *adapter)
        if (IS_ERR(adapter->ptp_clock)) {
                adapter->ptp_clock = NULL;
                dev_err(&adapter->pdev->dev, "ptp_clock_register failed\n");
-       } else {
+       } else if (adapter->ptp_clock) {
                dev_info(&adapter->pdev->dev, "added PHC on %s\n",
                         adapter->netdev->name);
                adapter->ptp_flags |= IGB_PTP_ENABLED;

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index e5431bf..a922776 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -1254,7 +1254,7 @@ static long ixgbe_ptp_create_clock(struct ixgbe_adapter *adapter)
                adapter->ptp_clock = NULL;
                e_dev_err("ptp_clock_register failed\n");
                return err;
-       } else
+       } else if (adapter->ptp_clock)
                e_dev_info("registered PHC device on %s\n", netdev->name);
 
        /* set default timestamp mode to disabled here. We do this in

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 1494997..08fc5fc 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -298,7 +298,7 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
        if (IS_ERR(mdev->ptp_clock)) {
                mdev->ptp_clock = NULL;
                mlx4_err(mdev, "ptp_clock_register failed\n");
-       } else {
+       } else if (mdev->ptp_clock) {
                mlx4_info(mdev, "registered PHC clock\n");
        }
 

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
index 847a8f3..13dc388 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_clock.c
@@ -273,7 +273,7 @@ void mlx5e_timestamp_init(struct mlx5e_priv *priv)
 
        tstamp->ptp = ptp_clock_register(&tstamp->ptp_info,
                                         &priv->mdev->pdev->dev);
-       if (IS_ERR_OR_NULL(tstamp->ptp)) {
+       if (IS_ERR(tstamp->ptp)) {
                mlx5_core_warn(priv->mdev, "ptp_clock_register failed %ld\n",
                               PTR_ERR(tstamp->ptp));
                tstamp->ptp = NULL;

diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index dd204d9..77a5364 100644 (file)
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -1269,13 +1269,13 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
                if (IS_ERR(ptp->phc_clock)) {
                        rc = PTR_ERR(ptp->phc_clock);
                        goto fail3;
-               }
-
-               INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
-               ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
-               if (!ptp->pps_workwq) {
-                       rc = -ENOMEM;
-                       goto fail4;
+               } else if (ptp->phc_clock) {
+                       INIT_WORK(&ptp->pps_work, efx_ptp_pps_worker);
+                       ptp->pps_workwq = create_singlethread_workqueue("sfc_pps");
+                       if (!ptp->pps_workwq) {
+                               rc = -ENOMEM;
+                               goto fail4;
+                       }
                }
        }
        ptp->nic_ts_enabled = false;

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index 170a18b..6e3b829 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -187,7 +187,7 @@ int stmmac_ptp_register(struct stmmac_priv *priv)
        if (IS_ERR(priv->ptp_clock)) {
                priv->ptp_clock = NULL;
                pr_err("ptp_clock_register() failed on %s\n", priv->dev->name);
-       } else
+       } else if (priv->ptp_clock)
                pr_debug("Added PTP HW clock successfully on %s\n",
                         priv->dev->name);
 

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 6b15e16..5ad54fc 100644 (file)
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -127,6 +127,11 @@ struct ptp_clock;
  *
  * @info:   Structure describing the new clock.
  * @parent: Pointer to the parent device of the new clock.
+ *
+ * Returns a valid pointer on success or PTR_ERR on failure.  If PHC
+ * support is missing at the configuration level, this function
+ * returns NULL, and drivers are expected to gracefully handle that
+ * case separately.
  */
 
 extern struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,