2021-01-28 09:16:00

by Uwe Kleine-König

Subject: [PATCH 1/2] i3c: Handle drivers without probe or remove callback

A registered driver without a probe callback doesn't make sense, so
refuse to register such a driver. (Otherwise i3c_device_probe() yields a
NULL pointer exception.)

A driver without remove is possible, e.g. when all resources are freed
using devm callbacks. So guard the call to driver->remove by a check
for being non-NULL.

Note that the only in-tree i3c driver
(drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c) doesn't have a remove
callback.

Signed-off-by: Uwe Kleine-König <[email protected]>
---
drivers/i3c/device.c | 5 +++++
drivers/i3c/master.c | 10 ++++++----
2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
index bb8e60dff988..e92d3e9a52bd 100644
--- a/drivers/i3c/device.c
+++ b/drivers/i3c/device.c
@@ -262,6 +262,11 @@ int i3c_driver_register_with_owner(struct i3c_driver *drv, struct module *owner)
drv->driver.owner = owner;
drv->driver.bus = &i3c_bus_type;

+ if (!drv->probe) {
+ pr_err("Trying to register an i3c driver without probe callback\n");
+ return -EINVAL;
+ }
+
return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(i3c_driver_register_with_owner);
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index b61bf53ec07a..57a4f699eb8d 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -326,11 +326,13 @@ static int i3c_device_remove(struct device *dev)
{
struct i3c_device *i3cdev = dev_to_i3cdev(dev);
struct i3c_driver *driver = drv_to_i3cdrv(dev->driver);
- int ret;
+ int ret = 0;

- ret = driver->remove(i3cdev);
- if (ret)
- return ret;
+ if (driver->remove) {
+ ret = driver->remove(i3cdev);
+ if (ret)
+ return ret;
+ }

i3c_device_free_ibi(i3cdev);

--
2.29.2

2021-02-01 23:22:42

by Alexandre Belloni

Subject: Re: [PATCH 1/2] i3c: Handle drivers without probe or remove callback

On Thu, 28 Jan 2021 10:10:47 +0100, Uwe Kleine-König wrote:
> A registered driver without a probe callback doesn't make sense, so
> refuse to register such a driver. (Otherwise i3c_device_probe() yields a
> NULL pointer exception.)
>
> A driver without remove is possible, e.g. when all resources are freed
> using devm callbacks. So guard the call to driver->remove by a check
> for being non-NULL.
>
> [...]

Applied, thanks!

[1/2] i3c: Handle drivers without probe or remove callback
commit: 7456fea589c6ad3422b0c188871ae80e1d307737
[2/2] i3c: Make remove callback return void
commit: dd9267034c0e364b49261c3e0070b863286d1242

Best regards,
--
Alexandre Belloni <[email protected]>