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 <stern@rowland.harvard.edu>
CC: Dmitry Torokhov <dmitry.torokhov@gmail.com>
CC: Kyungmin Park <kyungmin.park@samsung.com>
CC: Andy Walls <awalls@md.metrocast.net>
CC: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2012-01-24 13:34:24 -05:00
committed by Greg Kroah-Hartman
parent 2b31594a95
commit fde25a9b63
8 changed files with 10 additions and 17 deletions

View File

@@ -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);