On Tue, Jul 06 2021, Cornelia Huck <[email protected]> wrote:
> On Tue, Jul 06 2021, Uwe Kleine-König <[email protected]> wrote:
>
>> The driver core ignores the return value of this callback because there
>> is only little it can do when a device disappears.
>>
>> This is the final bit of a long lasting cleanup quest where several
>> buses were converted to also return void from their remove callback.
>> Additionally some resource leaks were fixed that were caused by drivers
>> returning an error code in the expectation that the driver won't go
>> away.
>>
>> With struct bus_type::remove returning void it's prevented that newly
>> implemented buses return an ignored error code and so don't anticipate
>> wrong expectations for driver authors.
>
> Yay!
>
>>
>> Signed-off-by: Uwe Kleine-König <[email protected]>
>> ---
>> Hello,
>>
>> this patch depends on "PCI: endpoint: Make struct pci_epf_driver::remove
>> return void" that is not yet applied, see
>> https://lore.kernel.org/r/[email protected].
>>
>> I tested it using allmodconfig on amd64 and arm, but I wouldn't be
>> surprised if I still missed to convert a driver. So it would be great to
>> get this into next early after the merge window closes.
>
> I'm afraid you missed the s390-specific busses in drivers/s390/cio/
> (css/ccw/ccwgroup).
The change for vfio/mdev looks good.
The following should do the trick for s390; not sure if other
architectures have easy-to-miss busses as well.
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 9748165e08e9..a66f416138ab 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -439,17 +439,15 @@ module_exit(cleanup_ccwgroup);
/************************** driver stuff ******************************/
-static int ccwgroup_remove(struct device *dev)
+static void ccwgroup_remove(struct device *dev)
{
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
if (!dev->driver)
- return 0;
+ return;
if (gdrv->remove)
gdrv->remove(gdev);
-
- return 0;
}
static void ccwgroup_shutdown(struct device *dev)
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index a974943c27da..ebc321edba51 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -1371,15 +1371,14 @@ static int css_probe(struct device *dev)
return ret;
}
-static int css_remove(struct device *dev)
+static void css_remove(struct device *dev)
{
struct subchannel *sch;
- int ret;
sch = to_subchannel(dev);
- ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
+ if (sch->driver->remove)
+ sch->driver->remove(sch);
sch->driver = NULL;
- return ret;
}
static void css_shutdown(struct device *dev)
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 84f659cafe76..61d5d55bd9c8 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1742,7 +1742,7 @@ ccw_device_probe (struct device *dev)
return 0;
}
-static int ccw_device_remove(struct device *dev)
+static void ccw_device_remove(struct device *dev)
{
struct ccw_device *cdev = to_ccwdev(dev);
struct ccw_driver *cdrv = cdev->drv;
@@ -1776,8 +1776,6 @@ static int ccw_device_remove(struct device *dev)
spin_unlock_irq(cdev->ccwlock);
io_subchannel_quiesce(sch);
__disable_cmf(cdev);
-
- return 0;
}
static void ccw_device_shutdown(struct device *dev)
diff --git a/drivers/s390/cio/scm.c b/drivers/s390/cio/scm.c
index 9f26d4310bb3..b6b4589c70bd 100644
--- a/drivers/s390/cio/scm.c
+++ b/drivers/s390/cio/scm.c
@@ -28,12 +28,13 @@ static int scmdev_probe(struct device *dev)
return scmdrv->probe ? scmdrv->probe(scmdev) : -ENODEV;
}
-static int scmdev_remove(struct device *dev)
+static void scmdev_remove(struct device *dev)
{
struct scm_device *scmdev = to_scm_dev(dev);
struct scm_driver *scmdrv = to_scm_drv(dev->driver);
- return scmdrv->remove ? scmdrv->remove(scmdev) : -ENODEV;
+ if (scmdrv->remove)
+ scmdrv->remove(scmdev);
}
static int scmdev_uevent(struct device *dev, struct kobj_uevent_env *env)
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index d2560186d771..8a0d37c0e2a5 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -884,7 +884,7 @@ static int ap_device_probe(struct device *dev)
return rc;
}
-static int ap_device_remove(struct device *dev)
+static void ap_device_remove(struct device *dev)
{
struct ap_device *ap_dev = to_ap_dev(dev);
struct ap_driver *ap_drv = ap_dev->drv;
@@ -909,8 +909,6 @@ static int ap_device_remove(struct device *dev)
ap_dev->drv = NULL;
put_device(dev);
-
- return 0;
}
struct ap_queue *ap_get_qdev(ap_qid_t qid)
On Tue, Jul 06, 2021 at 01:17:37PM +0200, Cornelia Huck wrote:
> On Tue, Jul 06 2021, Cornelia Huck <[email protected]> wrote:
>
> > On Tue, Jul 06 2021, Uwe Kleine-K?nig <[email protected]> wrote:
> >
> >> The driver core ignores the return value of this callback because there
> >> is only little it can do when a device disappears.
> >>
> >> This is the final bit of a long lasting cleanup quest where several
> >> buses were converted to also return void from their remove callback.
> >> Additionally some resource leaks were fixed that were caused by drivers
> >> returning an error code in the expectation that the driver won't go
> >> away.
> >>
> >> With struct bus_type::remove returning void it's prevented that newly
> >> implemented buses return an ignored error code and so don't anticipate
> >> wrong expectations for driver authors.
> >
> > Yay!
> >
> >>
> >> Signed-off-by: Uwe Kleine-K?nig <[email protected]>
> >> ---
> >> Hello,
> >>
> >> this patch depends on "PCI: endpoint: Make struct pci_epf_driver::remove
> >> return void" that is not yet applied, see
> >> https://lore.kernel.org/r/[email protected].
> >>
> >> I tested it using allmodconfig on amd64 and arm, but I wouldn't be
> >> surprised if I still missed to convert a driver. So it would be great to
> >> get this into next early after the merge window closes.
> >
> > I'm afraid you missed the s390-specific busses in drivers/s390/cio/
> > (css/ccw/ccwgroup).
:-\
> The change for vfio/mdev looks good.
>
> The following should do the trick for s390; not sure if other
> architectures have easy-to-miss busses as well.
>
> diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
> index 9748165e08e9..a66f416138ab 100644
> --- a/drivers/s390/cio/ccwgroup.c
> +++ b/drivers/s390/cio/ccwgroup.c
> @@ -439,17 +439,15 @@ module_exit(cleanup_ccwgroup);
>
> /************************** driver stuff ******************************/
>
> -static int ccwgroup_remove(struct device *dev)
> +static void ccwgroup_remove(struct device *dev)
> {
> struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
> struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
>
> if (!dev->driver)
> - return 0;
> + return;
This is fine to be squashed into my patch. In the long run: in a remove
callback dev->driver cannot be NULL, so this if could go away.
> if (gdrv->remove)
> gdrv->remove(gdev);
> -
> - return 0;
> }
>
> static void ccwgroup_shutdown(struct device *dev)
> diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
> index a974943c27da..ebc321edba51 100644
> --- a/drivers/s390/cio/css.c
> +++ b/drivers/s390/cio/css.c
> @@ -1371,15 +1371,14 @@ static int css_probe(struct device *dev)
> return ret;
> }
>
> -static int css_remove(struct device *dev)
> +static void css_remove(struct device *dev)
> {
> struct subchannel *sch;
> - int ret;
>
> sch = to_subchannel(dev);
> - ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
> + if (sch->driver->remove)
> + sch->driver->remove(sch);
Maybe the return type for this function pointer can be changed to void,
too.
I will add these changes to a v2 that I plan to send out after the dust
settles some more.
Thanks
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |