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Message-Id: <1235139447-5829-1-git-send-email-tom.leiming@gmail.com>
Date: Fri, 20 Feb 2009 22:17:27 +0800
From: tom.leiming@...il.com
To: kay.sievers@...y.org, greg@...ah.com
Cc: cornelia.huck@...ibm.com, arjan@...radead.org,
linux-kernel@...r.kernel.org, Ming Lei <tom.leiming@...il.com>
Subject: [PATCH] [PATCH/RESEND] driver core: remove polling for driver_probe_done(v4)
From: Ming Lei <tom.leiming@...il.com>
This patch adds a function : driver_wait_probe_done,
which waits on condition of probing done to replace
polling for driver_probe_done in fs initialization.
There is no better way to avoid polling for
driver_probe_done _and_ existence of the root device,
so we does not replace the driver_probe_done with
driver_wait_probe_done in such special case.
Removing polling in fs initialization may lead to
a faster boot.
This patch is against the latest linux-next tree.
Signed-off-by: Ming Lei <tom.leiming@...il.com>
Acked-by: Cornelia Huck <cornelia.huck@...ibm.com>
Reviewed-by: Arjan van de Ven <arjan@...ux.intel.com>
---
drivers/base/dd.c | 15 ++++++---------
include/linux/device.h | 2 +-
init/do_mounts.c | 2 +-
init/do_mounts_md.c | 2 +-
4 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 62a31b9..fef201c 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -170,18 +170,15 @@ int driver_probe_done(void)
}
/**
- * wait_for_device_probe
- * Wait for device probing to be completed.
+ * driver_wait_probe_done
+ * Wait until the probe sequence is finished.
*
- * Note: this function polls at 100 msec intervals.
*/
-int wait_for_device_probe(void)
+void driver_wait_probe_done(void)
{
- /* wait for the known devices to complete their probing */
- while (driver_probe_done() != 0)
- msleep(100);
- async_synchronize_full();
- return 0;
+ pr_debug("%s: probe_count = %d\n", __func__,
+ atomic_read(&probe_count));
+ wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
}
/**
diff --git a/include/linux/device.h b/include/linux/device.h
index f6d6270..4527064 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -148,7 +148,7 @@ 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);
+extern void driver_wait_probe_done(void);
/* sysfs interface for exporting driver attributes */
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 8d4ff5a..01be2cd 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -377,7 +377,7 @@ void __init prepare_namespace(void)
* For example, it is not atypical to wait 5 seconds here
* for the touchpad of a laptop to initialize.
*/
- wait_for_device_probe();
+ driver_wait_probe_done();
md_run_setup();
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index 9bdddbc..bcea03b 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -282,7 +282,7 @@ 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");
- wait_for_device_probe();
+ driver_wait_probe_done();
fd = sys_open("/dev/md0", 0, 0);
if (fd >= 0) {
--
1.6.0.GIT
--
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