Consolidate driver_probe_done() loops into one place
Arjan van de Ven [Sat, 14 Feb 2009 00:59:06 +0000 (01:59 +0100)]
there's a few places that currently loop over driver_probe_done(), and
I'm about to add another one. This patch abstracts it into a helper
to reduce duplication.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/dd.c
include/linux/device.h
init/do_mounts.c
init/do_mounts_md.c

index 315bed8..1352312 100644 (file)
  */
 
 #include <linux/device.h>
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/wait.h>
+#include <linux/async.h>
 
 #include "base.h"
 #include "power/power.h"
@@ -168,6 +170,21 @@ int driver_probe_done(void)
 }
 
 /**
+ * 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
  * @dev: device to try to bind to the driver
index 45e5b19..47f343c 100644 (file)
@@ -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 */
 
index 708105e..8d4ff5a 100644 (file)
@@ -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;
index ff95e31..9bdddbc 100644 (file)
@@ -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);