diff options
| -rw-r--r-- | drivers/base/core.c | 29 | ||||
| -rw-r--r-- | drivers/s390/cio/ccwgroup.c | 18 | ||||
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 14 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 54 | ||||
| -rw-r--r-- | include/linux/device.h | 2 | ||||
| -rw-r--r-- | include/linux/sysfs.h | 9 |
6 files changed, 122 insertions, 4 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index f191afe62b4d..ad0f4a2f25c4 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -407,6 +407,35 @@ void device_remove_bin_file(struct device *dev, struct bin_attribute *attr) } EXPORT_SYMBOL_GPL(device_remove_bin_file); +/** + * device_schedule_callback - helper to schedule a callback for a device + * @dev: device. + * @func: callback function to invoke later. + * + * Attribute methods must not unregister themselves or their parent device + * (which would amount to the same thing). Attempts to do so will deadlock, + * since unregistration is mutually exclusive with driver callbacks. + * + * Instead methods can call this routine, which will attempt to allocate + * and schedule a workqueue request to call back @func with @dev as its + * argument in the workqueue's process context. @dev will be pinned until + * @func returns. + * + * Returns 0 if the request was submitted, -ENOMEM if storage could not + * be allocated. + * + * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an + * underlying sysfs routine (since it is intended for use by attribute + * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. + */ +int device_schedule_callback(struct device *dev, + void (*func)(struct device *)) +{ + return sysfs_schedule_callback(&dev->kobj, + (void (*)(void *)) func, dev); +} +EXPORT_SYMBOL_GPL(device_schedule_callback); + static void klist_children_get(struct klist_node *n) { struct device *dev = container_of(n, struct device, knode_parent); diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c index d48e3ca4752c..5aeb68e732b0 100644 --- a/drivers/s390/cio/ccwgroup.c +++ b/drivers/s390/cio/ccwgroup.c @@ -71,19 +71,31 @@ __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev) * Provide an 'ungroup' attribute so the user can remove group devices no * longer needed or accidentially created. Saves memory :) */ +static void ccwgroup_ungroup_callback(struct device *dev) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + + __ccwgroup_remove_symlinks(gdev); + device_unregister(dev); +} + static ssize_t ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ccwgroup_device *gdev; + int rc; gdev = to_ccwgroupdev(dev); if (gdev->state != CCWGROUP_OFFLINE) return -EINVAL; - __ccwgroup_remove_symlinks(gdev); - device_unregister(dev); - + /* Note that we cannot unregister the device from one of its + * attribute methods, so we have to use this roundabout approach. + */ + rc = device_schedule_callback(dev, ccwgroup_ungroup_callback); + if (rc) + count = rc; return count; } diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index c275dcac3f18..939de0de18bc 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -452,10 +452,22 @@ store_rescan_field (struct device *dev, struct device_attribute *attr, const cha } static DEVICE_ATTR(rescan, S_IWUSR, NULL, store_rescan_field); +static void sdev_store_delete_callback(struct device *dev) +{ + scsi_remove_device(to_scsi_device(dev)); +} + static ssize_t sdev_store_delete(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - scsi_remove_device(to_scsi_device(dev)); + int rc; + + /* An attribute cannot be unregistered by one of its own methods, + * so we have to use this roundabout approach. + */ + rc = device_schedule_callback(dev, sdev_store_delete_callback); + if (rc) + count = rc; return count; }; static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete); diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 8d4d839a9d88..1bafdf6e171c 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -629,6 +629,60 @@ void sysfs_remove_file_from_group(struct kobject *kobj, } EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); +struct sysfs_schedule_callback_struct { + struct kobject *kobj; + void (*func)(void *); + void *data; + struct work_struct work; +}; + +static void sysfs_schedule_callback_work(struct work_struct *work) +{ + struct sysfs_schedule_callback_struct *ss = container_of(work, + struct sysfs_schedule_callback_struct, work); + + (ss->func)(ss->data); + kobject_put(ss->kobj); + kfree(ss); +} + +/** + * sysfs_schedule_callback - helper to schedule a callback for a kobject + * @kobj: object we're acting for. + * @func: callback function to invoke later. + * @data: argument to pass to @func. + * + * sysfs attribute methods must not unregister themselves or their parent + * kobject (which would amount to the same thing). Attempts to do so will + * deadlock, since unregistration is mutually exclusive with driver + * callbacks. + * + * Instead methods can call this routine, which will attempt to allocate + * and schedule a workqueue request to call back @func with @data as its + * argument in the workqueue's process context. @kobj will be pinned + * until @func returns. + * + * Returns 0 if the request was submitted, -ENOMEM if storage could not + * be allocated. + */ +int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), + void *data) +{ + struct sysfs_schedule_callback_struct *ss; + + ss = kmalloc(sizeof(*ss), GFP_KERNEL); + if (!ss) + return -ENOMEM; + kobject_get(kobj); + ss->kobj = kobj; + ss->func = func; + ss->data = data; + INIT_WORK(&ss->work, sysfs_schedule_callback_work); + schedule_work(&ss->work); + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_schedule_callback); + EXPORT_SYMBOL_GPL(sysfs_create_file); EXPORT_SYMBOL_GPL(sysfs_remove_file); diff --git a/include/linux/device.h b/include/linux/device.h index 39a3199a826d..caad9bba9652 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -353,6 +353,8 @@ extern int __must_check device_create_bin_file(struct device *dev, struct bin_attribute *attr); extern void device_remove_bin_file(struct device *dev, struct bin_attribute *attr); +extern int device_schedule_callback(struct device *dev, + void (*func)(struct device *)); /* device resource management */ typedef void (*dr_release_t)(struct device *dev, void *res); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 523405e1e1f6..0544edda7168 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -78,6 +78,9 @@ struct sysfs_ops { #ifdef CONFIG_SYSFS +extern int sysfs_schedule_callback(struct kobject *kobj, + void (*func)(void *), void *data); + extern int __must_check sysfs_create_dir(struct kobject *, struct dentry *); @@ -132,6 +135,12 @@ extern int __must_check sysfs_init(void); #else /* CONFIG_SYSFS */ +static inline int sysfs_schedule_callback(struct kobject *kobj, + void (*func)(void *), void *data) +{ + return -ENOSYS; +} + static inline int sysfs_create_dir(struct kobject * k, struct dentry *shadow) { return 0; |