Miscdevice now supports revocable fops replacement. Use it to secure the cros_ec_device.
Signed-off-by: Tzung-Bi Shih <[email protected]> --- PoC patch. v4: - New in the series. drivers/platform/chrome/cros_ec_chardev.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c index c9d80ad5b57e..cacc73635d6b 100644 --- a/drivers/platform/chrome/cros_ec_chardev.c +++ b/drivers/platform/chrome/cros_ec_chardev.c @@ -166,7 +166,6 @@ static int cros_ec_chardev_open(struct inode *inode, struct file *filp) if (!priv) return -ENOMEM; - priv->ec_dev = ec_dev; priv->cmd_offset = ec->cmd_offset; filp->private_data = priv; INIT_LIST_HEAD(&priv->events); @@ -370,6 +369,18 @@ static const struct file_operations chardev_fops = { #endif }; +static int cros_ec_chardev_rev_try_access(struct revocable *rev, void *data) +{ + struct chardev_priv *priv = data; + + priv->ec_dev = revocable_try_access(rev); + return priv->ec_dev ? 0 : -ENODEV; +} + +static const struct revocable_operations cros_ec_chardev_rops = { + .try_access = cros_ec_chardev_rev_try_access, +}; + static int cros_ec_chardev_probe(struct platform_device *pdev) { struct cros_ec_dev *ec = dev_get_drvdata(pdev->dev.parent); @@ -385,6 +396,8 @@ static int cros_ec_chardev_probe(struct platform_device *pdev) misc->fops = &chardev_fops; misc->name = ec_platform->ec_name; misc->parent = pdev->dev.parent; + misc->rp = ec->ec_dev->revocable_provider; + misc->rops = &cros_ec_chardev_rops; dev_set_drvdata(&pdev->dev, misc); -- 2.51.0.534.gc79095c0ca-goog
