diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 315bed8d5e7f..135231239103 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -18,9 +18,11 @@ */ #include +#include #include #include #include +#include #include "base.h" #include "power/power.h" @@ -167,6 +169,21 @@ int driver_probe_done(void) return 0; } +/** + * wait_for_device_probe + * Wait for device probing to be completed. + * + * Note: this function polls at 100 msec intervals. + */ +int wait_for_device_probe(void) +{ + /* wait for the known devices to complete their probing */ + while (driver_probe_done() != 0) + msleep(100); + async_synchronize_full(); + return 0; +} + /** * driver_probe_device - attempt to bind device & driver together * @drv: driver to bind a device to diff --git a/include/linux/device.h b/include/linux/device.h index 45e5b1921fbb..47f343c7bdda 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -147,6 +147,8 @@ extern void put_driver(struct device_driver *drv); extern struct device_driver *driver_find(const char *name, struct bus_type *bus); extern int driver_probe_done(void); +extern int wait_for_device_probe(void); + /* sysfs interface for exporting driver attributes */ diff --git a/init/do_mounts.c b/init/do_mounts.c index 708105e163df..8d4ff5afc1d8 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -370,10 +370,14 @@ void __init prepare_namespace(void) ssleep(root_delay); } - /* wait for the known devices to complete their probing */ - while (driver_probe_done() != 0) - msleep(100); - async_synchronize_full(); + /* + * wait for the known devices to complete their probing + * + * Note: this is a potential source of long boot delays. + * For example, it is not atypical to wait 5 seconds here + * for the touchpad of a laptop to initialize. + */ + wait_for_device_probe(); md_run_setup(); @@ -399,6 +403,7 @@ void __init prepare_namespace(void) while (driver_probe_done() != 0 || (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) msleep(100); + async_synchronize_full(); } is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c index ff95e3192884..9bdddbcb3d6a 100644 --- a/init/do_mounts_md.c +++ b/init/do_mounts_md.c @@ -281,8 +281,9 @@ static void __init autodetect_raid(void) */ printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n"); printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n"); - while (driver_probe_done() < 0) - msleep(100); + + wait_for_device_probe(); + fd = sys_open("/dev/md0", 0, 0); if (fd >= 0) { sys_ioctl(fd, RAID_AUTORUN, raid_autopart);