Linux Kernel设备驱动模型之 总线查找驱动

设备模型之总线查找驱动：

/** * bus_for_each_drv - driver iterator * @bus: bus we're dealing with. * @start: driver to start iterating on. * @data: data to pass to the callback. * @fn: function to call for each driver. * * This is nearly identical to the device iterator above. * We iterate over each driver that belongs to @bus, and call * @fn for each. If @fn returns anything but 0, we break out * and return it. If @start is not NULL, we use it as the head * of the list. * * NOTE: we don't return the driver that returns a non-zero * value, nor do we leave the reference count incremented for that * driver. If the caller needs to know that info, it must set it * in the callback. It must also be sure to increment the refcount * so it doesn't disappear before returning to the caller. */int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,       void *data, int (*fn)(struct device_driver *, void *)){ struct klist_iter i; struct device_driver *drv; int error = 0;
 if (!bus)  return -EINVAL;
 klist_iter_init_node(&bus->p->klist_drivers, &i,        start ? &start->p->knode_bus : NULL); while ((drv = next_driver(&i)) && !error)  error = fn(drv, data); klist_iter_exit(&i); return error;}
 
static struct device_driver *next_driver(struct klist_iter *i){ struct klist_node *n = klist_next(i); struct driver_private *drv_priv;
 if (n) {  drv_priv = container_of(n, struct driver_private, knode_bus);  return drv_priv->driver; } return NULL;}