Re: [PATCH] bus: Make remove callback return void
From: Cornelia Huck <cohuck@redhat.com>
Date: 2021-07-06 11:24:52
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Subsystem:
s390 architecture, s390 common i/o layer, s390 scm driver, s390 zcrypt and pkey driver and ap bus, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Vineeth Vijayan, Peter Oberparleiter, Harald Freudenberger, Holger Dengler, Linus Torvalds
On Tue, Jul 06 2021, Cornelia Huck [off-list ref] wrote:
On Tue, Jul 06 2021, Uwe Kleine-König [off-list ref] wrote:quoted
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!quoted
Signed-off-by: Uwe Kleine-König <redacted> --- 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/20210223090757.57604-1-u.kleine-koenig@pengutronix.de (local). 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)