[PATCH v3 2/2] can: bittiming: change can_calc_tdco()'s prototype to not directly modify priv

From: Vincent Mailhol
Date: Mon Sep 06 2021 - 12:04:07 EST


In previous commit, we introduced a temporary priv variable in
can_changelink(), wrote the changes to it and committed all changes at
the very end of the function.

However, the function can_calc_tdco() directly retrieves can_priv from
the net_device and directly modifies it. We change the prototype so
that it instead writes its changes to a struct can_priv that is passed
as an argument. This way, can_changelink() can pass the newly
introduced temporary priv variable.


Fixes: c25cc7993243 ("can: bittiming: add calculation for CAN FD Transmitter Delay Compensation (TDC)")
Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
---
drivers/net/can/dev/bittiming.c | 8 ++------
drivers/net/can/dev/netlink.c | 2 +-
include/linux/can/bittiming.h | 7 +++++--
3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c
index f49170eadd54..bddd93e2e439 100644
--- a/drivers/net/can/dev/bittiming.c
+++ b/drivers/net/can/dev/bittiming.c
@@ -175,13 +175,9 @@ int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
return 0;
}

-void can_calc_tdco(struct net_device *dev)
+void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
+ const struct can_bittiming *dbt)
{
- struct can_priv *priv = netdev_priv(dev);
- const struct can_bittiming *dbt = &priv->data_bittiming;
- struct can_tdc *tdc = &priv->tdc;
- const struct can_tdc_const *tdc_const = priv->tdc_const;
-
if (!tdc_const)
return;

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 21b76ca8cb22..66815ea6046e 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -190,7 +190,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
return -EINVAL;
}

- can_calc_tdco(dev);
+ can_calc_tdco(&priv->tdc, priv->tdc_const, &priv->data_bittiming);

if (priv->do_set_data_bittiming) {
/* Finally, set the bit-timing registers */
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 9de6e9053e34..b3c1711ee0f0 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -87,7 +87,8 @@ struct can_tdc_const {
int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc);

-void can_calc_tdco(struct net_device *dev);
+void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
+ const struct can_bittiming *dbt);
#else /* !CONFIG_CAN_CALC_BITTIMING */
static inline int
can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
@@ -97,7 +98,9 @@ can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
return -EINVAL;
}

-static inline void can_calc_tdco(struct net_device *dev)
+static inline void
+can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
+ const struct can_bittiming *dbt)
{
}
#endif /* CONFIG_CAN_CALC_BITTIMING */
--
2.32.0