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w1: remove race with sysfs file creation

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W1 slave sysfs files are created _after_ userspace is notified that the
device has been added to the system.  Fix that race by moving the
creation/remove of the files to the bus notifier that is there for doing
this type of thing.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2013-08-21 13:24:32 -07:00
parent 3e1026b3fa
commit 47eba33a09
1 changed files with 73 additions and 38 deletions
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111
drivers/w1/w1.c
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@ -587,6 +587,73 @@ end:
return err;
}
/*
* Handle sysfs file creation and removal here, before userspace is told that
* the device is added / removed from the system
*/
static int w1_bus_notify(struct notifier_block *nb, unsigned long action,
void *data)
{
struct device *dev = data;
struct w1_slave *sl;
int err;
/*
* Only care about slave devices at the moment. Yes, we should use a
* separate "type" for this, but for now, look at the release function
* to know which type it is...
*/
if (dev->release != w1_slave_release)
return 0;
sl = dev_to_w1_slave(dev);
switch (action) {
case BUS_NOTIFY_ADD_DEVICE:
/* Create our sysfs files before userspace is told about it */
/* Create "name" entry */
err = device_create_file(&sl->dev, &w1_slave_attr_name);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
return err;
}
/* Create "id" entry */
err = device_create_file(&sl->dev, &w1_slave_attr_id);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
return err;
}
/* if the family driver needs to initialize something... */
if (sl->family->fops && sl->family->fops->add_slave &&
((err = sl->family->fops->add_slave(sl)) < 0)) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
return err;
}
break;
case BUS_NOTIFY_DEL_DEVICE:
/* Remove our sysfs files */
if (sl->family->fops && sl->family->fops->remove_slave)
sl->family->fops->remove_slave(sl);
device_remove_file(&sl->dev, &w1_slave_attr_id);
device_remove_file(&sl->dev, &w1_slave_attr_name);
break;
}
return 0;
}
static struct notifier_block w1_bus_nb = {
.notifier_call = w1_bus_notify,
};
static int __w1_attach_slave_device(struct w1_slave *sl)
{
int err;
@ -615,44 +682,13 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
return err;
}
/* Create "name" entry */
err = device_create_file(&sl->dev, &w1_slave_attr_name);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
goto out_unreg;
}
/* Create "id" entry */
err = device_create_file(&sl->dev, &w1_slave_attr_id);
if (err < 0) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
goto out_rem1;
}
/* if the family driver needs to initialize something... */
if (sl->family->fops && sl->family->fops->add_slave &&
((err = sl->family->fops->add_slave(sl)) < 0)) {
dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n",
dev_name(&sl->dev), err);
goto out_rem2;
}
dev_set_uevent_suppress(&sl->dev, false);
kobject_uevent(&sl->dev.kobj, KOBJ_ADD);
list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
return 0;
out_rem2:
device_remove_file(&sl->dev, &w1_slave_attr_id);
out_rem1:
device_remove_file(&sl->dev, &w1_slave_attr_name);
out_unreg:
device_unregister(&sl->dev);
return err;
}
static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
@ -723,16 +759,11 @@ void w1_slave_detach(struct w1_slave *sl)
list_del(&sl->w1_slave_entry);
if (sl->family->fops && sl->family->fops->remove_slave)
sl->family->fops->remove_slave(sl);
memset(&msg, 0, sizeof(msg));
memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
msg.type = W1_SLAVE_REMOVE;
w1_netlink_send(sl->master, &msg);
device_remove_file(&sl->dev, &w1_slave_attr_id);
device_remove_file(&sl->dev, &w1_slave_attr_name);
device_unregister(&sl->dev);
wait_for_completion(&sl->released);
@ -1017,6 +1048,10 @@ static int __init w1_init(void)
goto err_out_exit_init;
}
retval = bus_register_notifier(&w1_bus_type, &w1_bus_nb);
if (retval)
goto err_out_bus_unregister;
retval = driver_register(&w1_master_driver);
if (retval) {
printk(KERN_ERR