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device_schedule_callback() needs a module reference

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This patch (as896b) fixes an oversight in the design of
device_schedule_callback().  It is necessary to acquire a reference to the
module owning the callback routine, to prevent the module from being
unloaded before the callback can run.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2007-04-26 00:12:04 -07:00
committed by Greg Kroah-Hartman
parent fa1a8c23eb
commit 523ded71de
4 changed files with 29 additions and 13 deletions
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14
fs/sysfs/file.c
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@@ -633,6 +633,7 @@ struct sysfs_schedule_callback_struct {
struct kobject *kobj;
void (*func)(void *);
void *data;
struct module *owner;
struct work_struct work;
};
@@ -643,6 +644,7 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
(ss->func)(ss->data);
kobject_put(ss->kobj);
module_put(ss->owner);
kfree(ss);
}
@@ -651,6 +653,7 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
* @kobj: object we're acting for.
* @func: callback function to invoke later.
* @data: argument to pass to @func.
* @owner: module owning the callback code
*
* sysfs attribute methods must not unregister themselves or their parent
* kobject (which would amount to the same thing). Attempts to do so will
@@ -663,20 +666,25 @@ static void sysfs_schedule_callback_work(struct work_struct *work)
* until @func returns.
*
* Returns 0 if the request was submitted, -ENOMEM if storage could not
* be allocated.
* be allocated, -ENODEV if a reference to @owner isn't available.
*/
int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
void *data)
void *data, struct module *owner)
{
struct sysfs_schedule_callback_struct *ss;
if (!try_module_get(owner))
return -ENODEV;
ss = kmalloc(sizeof(*ss), GFP_KERNEL);
if (!ss)
if (!ss) {
module_put(owner);
return -ENOMEM;
}
kobject_get(kobj);
ss->kobj = kobj;
ss->func = func;
ss->data = data;
ss->owner = owner;
INIT_WORK(&ss->work, sysfs_schedule_callback_work);
schedule_work(&ss->work);
return 0;