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Subject[PATCH 1/2] consolidate driver_probe_done() loops into one place
From 11b47973023398ecdb933c442bab120906946762 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Fri, 9 Jan 2009 21:04:53 -0800
Subject: [PATCH] consolidate driver_probe_done() loops into one place

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>
---
drivers/base/dd.c | 16 ++++++++++++++++
include/linux/device.h | 2 ++
init/do_mounts.c | 13 +++++++++----
init/do_mounts_md.c | 5 +++--
4 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 315bed8..b911fab 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -21,6 +21,7 @@
#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 +169,21 @@ 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
diff --git a/include/linux/device.h b/include/linux/device.h
index 45e5b19..47f343c 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 708105e..2c80113 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 ff95e31..9bdddbc 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);
--
1.6.0.6


--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org


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