From 47eba33a0997fc7362ae41cf28cea687e28bd731 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 21 Aug 2013 13:24:32 -0700 Subject: w1: remove race with sysfs file creation 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 Signed-off-by: Greg Kroah-Hartman --- drivers/w1/w1.c | 111 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 73 insertions(+), 38 deletions(-) diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 0459df843c58..3c798db0152c 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -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 -- cgit v1.2.3