diff options
Diffstat (limited to 'drivers')
| -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 |
3 files changed, 57 insertions, 4 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index f191afe62b4..ad0f4a2f25c 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 d48e3ca4752..5aeb68e732b 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 c275dcac3f1..939de0de18b 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); |