From fde25a9b63b9a3dc91365c394a426ebe64cfc2da Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 24 Jan 2012 13:34:24 -0500 Subject: Driver core: driver_find() drops reference before returning As part of the removal of get_driver()/put_driver(), this patch (as1510) changes driver_find(); it now drops the reference it acquires before returning. The patch also adjusts all the callers of driver_find() to remove the now unnecessary calls to put_driver(). In addition, the patch adds a warning to driver_find(): Callers must make sure the driver they are searching for does not get unloaded while they are using it. This has always been the case; driver_find() has never prevented a driver from being unregistered or unloaded. Hence the patch will not introduce any new bugs. The existing callers all seem to be okay in this respect, however I don't understand the video drivers well enough to be certain about them. Signed-off-by: Alan Stern CC: Dmitry Torokhov CC: Kyungmin Park CC: Andy Walls CC: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- drivers/s390/net/smsgiucv_app.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'drivers/s390') diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c index 4d2ea4000422..32515a201bbc 100644 --- a/drivers/s390/net/smsgiucv_app.c +++ b/drivers/s390/net/smsgiucv_app.c @@ -168,7 +168,7 @@ static int __init smsgiucv_app_init(void) rc = dev_set_name(smsg_app_dev, KMSG_COMPONENT); if (rc) { kfree(smsg_app_dev); - goto fail_put_driver; + goto fail; } smsg_app_dev->bus = &iucv_bus; smsg_app_dev->parent = iucv_root; @@ -177,7 +177,7 @@ static int __init smsgiucv_app_init(void) rc = device_register(smsg_app_dev); if (rc) { put_device(smsg_app_dev); - goto fail_put_driver; + goto fail; } /* convert sender to uppercase characters */ @@ -191,12 +191,11 @@ static int __init smsgiucv_app_init(void) rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback); if (rc) { device_unregister(smsg_app_dev); - goto fail_put_driver; + goto fail; } rc = 0; -fail_put_driver: - put_driver(smsgiucv_drv); +fail: return rc; } module_init(smsgiucv_app_init); -- cgit v1.2.3 From 9f30ea950edfaefa51221dd26a065b3442599778 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Tue, 24 Jan 2012 13:35:02 -0500 Subject: cio: remove {get,put}_driver Remove useless {get,put}_driver - the caller of the functions has to ensure valid driver pointers. Signed-off-by: Sebastian Ott Signed-off-by: Alan Stern CC: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- drivers/s390/cio/ccwgroup.c | 2 -- drivers/s390/cio/device.c | 8 +------- 2 files changed, 1 insertion(+), 9 deletions(-) (limited to 'drivers/s390') diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c index 4f1989d27b1f..5f1dc6fb5708 100644 --- a/drivers/s390/cio/ccwgroup.c +++ b/drivers/s390/cio/ccwgroup.c @@ -580,7 +580,6 @@ void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver) struct device *dev; /* We don't want ccwgroup devices to live longer than their driver. */ - get_driver(&cdriver->driver); while ((dev = driver_find_device(&cdriver->driver, NULL, NULL, __ccwgroup_match_all))) { struct ccwgroup_device *gdev = to_ccwgroupdev(dev); @@ -592,7 +591,6 @@ void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver) mutex_unlock(&gdev->reg_mutex); put_device(dev); } - put_driver(&cdriver->driver); driver_unregister(&cdriver->driver); } EXPORT_SYMBOL(ccwgroup_driver_unregister); diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c index 47269858ecb6..02d015259461 100644 --- a/drivers/s390/cio/device.c +++ b/drivers/s390/cio/device.c @@ -1676,15 +1676,9 @@ struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv, const char *bus_id) { struct device *dev; - struct device_driver *drv; - drv = get_driver(&cdrv->driver); - if (!drv) - return NULL; - - dev = driver_find_device(drv, NULL, (void *)bus_id, + dev = driver_find_device(&cdrv->driver, NULL, (void *)bus_id, __ccwdev_check_busid); - put_driver(drv); return dev ? to_ccwdev(dev) : NULL; } -- cgit v1.2.3