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can: dev: add sanity check in can_set_static_ctrlmode()

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Previous patch removed can_priv::ctrlmode_static to replace it with
can_get_static_ctrlmode().

A condition sine qua non for this to work is that the controller
static modes should never be set in can_priv::ctrlmode_supported
(c.f. the comment on can_priv::ctrlmode_supported which states that it
is for "options that can be *modified* by netlink"). Also, this
condition is already correctly fulfilled by all existing drivers
which rely on the ctrlmode_static feature.

Nonetheless, we added an extra safeguard in can_set_static_ctrlmode()
to return an error value and to warn the developer who would be
adventurous enough to set to static a given feature that is already
set to supported.

The drivers which rely on the static controller mode are then updated
to check the return value of can_set_static_ctrlmode().

Link: https://lore.kernel.org/all/20211213160226.56219-3-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Vincent Mailhol 2021-12-14 01:02:24 +09:00 • committed by Marc Kleine-Budde
parent c9e1d8ed30
commit 7d4a101c0b
3 changed files with 19 additions and 6 deletions
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11
include/linux/can/dev.h
View file

@ -131,17 +131,24 @@ static inline s32 can_get_relative_tdco(const struct can_priv *priv)
}
/* helper to define static CAN controller features at device creation time */
static inline void can_set_static_ctrlmode(struct net_device *dev,
u32 static_mode)
static inline int __must_check can_set_static_ctrlmode(struct net_device *dev,
u32 static_mode)
{
struct can_priv *priv = netdev_priv(dev);
/* alloc_candev() succeeded => netdev_priv() is valid at this point */
if (priv->ctrlmode_supported & static_mode) {
netdev_warn(dev,
"Controller features can not be supported and static at the same time\n");
return -EINVAL;
}
priv->ctrlmode = static_mode;
/* override MTU which was set by default in can_setup()? */
if (static_mode & CAN_CTRLMODE_FD)
dev->mtu = CANFD_MTU;
return 0;
}
static inline u32 can_get_static_ctrlmode(struct can_priv *priv)