* [PATCH 1/2] i3c: Handle drivers without probe or remove callback
@ 2021-01-28 9:10 Uwe Kleine-König
2021-01-28 9:10 ` [PATCH 2/2] i3c: Make remove callback return void Uwe Kleine-König
2021-02-01 23:17 ` [PATCH 1/2] i3c: Handle drivers without probe or remove callback Alexandre Belloni
0 siblings, 2 replies; 3+ messages in thread
From: Uwe Kleine-König @ 2021-01-28 9:10 UTC (permalink / raw)
To: Alexandre Belloni; +Cc: Greg Kroah-Hartman, linux-i3c, linux-kernel, kernel
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 <u.kleine-koenig@pengutronix.de>
---
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
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^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] i3c: Make remove callback return void
2021-01-28 9:10 [PATCH 1/2] i3c: Handle drivers without probe or remove callback Uwe Kleine-König
@ 2021-01-28 9:10 ` Uwe Kleine-König
2021-02-01 23:17 ` [PATCH 1/2] i3c: Handle drivers without probe or remove callback Alexandre Belloni
1 sibling, 0 replies; 3+ messages in thread
From: Uwe Kleine-König @ 2021-01-28 9:10 UTC (permalink / raw)
To: Alexandre Belloni; +Cc: Greg Kroah-Hartman, linux-i3c, linux-kernel, kernel
The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct i3c_driver::remove() return
void, too. This makes it obvious that returning an error code is
a bad idea and future driver authors cannot get that wrong.
Up to now there are no drivers with a remove callback, so there is no
need to adapt drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
drivers/i3c/master.c | 10 +++-------
include/linux/i3c/device.h | 2 +-
2 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 57a4f699eb8d..f8e9b7305c13 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -326,17 +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 = 0;
- if (driver->remove) {
- ret = driver->remove(i3cdev);
- if (ret)
- return ret;
- }
+ if (driver->remove)
+ driver->remove(i3cdev);
i3c_device_free_ibi(i3cdev);
- return ret;
+ return 0;
}
struct bus_type i3c_bus_type = {
diff --git a/include/linux/i3c/device.h b/include/linux/i3c/device.h
index de102e4418ab..8242e13e7b0b 100644
--- a/include/linux/i3c/device.h
+++ b/include/linux/i3c/device.h
@@ -176,7 +176,7 @@ struct i3c_device;
struct i3c_driver {
struct device_driver driver;
int (*probe)(struct i3c_device *dev);
- int (*remove)(struct i3c_device *dev);
+ void (*remove)(struct i3c_device *dev);
const struct i3c_device_id *id_table;
};
--
2.29.2
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH 1/2] i3c: Handle drivers without probe or remove callback
2021-01-28 9:10 [PATCH 1/2] i3c: Handle drivers without probe or remove callback Uwe Kleine-König
2021-01-28 9:10 ` [PATCH 2/2] i3c: Make remove callback return void Uwe Kleine-König
@ 2021-02-01 23:17 ` Alexandre Belloni
1 sibling, 0 replies; 3+ messages in thread
From: Alexandre Belloni @ 2021-02-01 23:17 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: Greg Kroah-Hartman, Alexandre Belloni, linux-i3c, linux-kernel, kernel
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,
--
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-01-28 9:10 [PATCH 1/2] i3c: Handle drivers without probe or remove callback Uwe Kleine-König
2021-01-28 9:10 ` [PATCH 2/2] i3c: Make remove callback return void Uwe Kleine-König
2021-02-01 23:17 ` [PATCH 1/2] i3c: Handle drivers without probe or remove callback Alexandre Belloni
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