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driver core: check bus->match without holding device lock

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From: Linux Kernel Mailing List
Subject: driver core: check bus->match without holding device lock
Date: Thursday, March 26, 2009 - 12:26 pm

Gitweb:     http://git.kernel.org/linus/49b420a13ff95b449947181190b08367348e3e1b
Commit:     49b420a13ff95b449947181190b08367348e3e1b
Parent:     4a67a1bc0b3a0db017b560cee27370d141c58e25
Author:     Ming Lei <tom.leiming@gmail.com>
AuthorDate: Wed Jan 21 23:27:47 2009 +0800
Committer:  Greg Kroah-Hartman <gregkh@suse.de>
CommitDate: Tue Mar 24 16:38:24 2009 -0700

    driver core: check bus->match without holding device lock
    
    This patch moves bus->match out from driver_probe_device and
    does not hold device lock to check the match between a device
    and a driver.
    
    The idea has been verified by the commit 6cd495860901,
    which leads to a faster boot. But the commit 6cd495860901 has
    the following drawbacks: 1),only does the quick check in
    the path of __driver_attach->driver_probe_device, not in other
    paths; 2),for a matched device and driver, check the same match
    twice. It is a waste of cpu ,especially for some drivers with long
    device id table (eg. usb-storage driver).
    
    This patch adds a helper of driver_match_device to check the match
    in all paths, and testes the match only once.
    
    Signed-off-by: Ming Lei <tom.leiming@gmail.com>
    Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/base/base.h |    5 +++++
 drivers/base/bus.c  |    2 +-
 drivers/base/dd.c   |   19 +++++++------------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/base/base.h b/drivers/base/base.h
index 9f50f1b..ca2b037 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -86,6 +86,11 @@ extern void bus_remove_driver(struct device_driver *drv);
 
 extern void driver_detach(struct device_driver *drv);
 extern int driver_probe_device(struct device_driver *drv, struct device *dev);
+static inline int driver_match_device(struct device_driver *drv,
+				      struct device *dev)
+{
+	return drv->bus->match && drv->bus->match(dev, ...
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Previous thread: sysfs: Take sysfs_mutex when fetching the root inode. by Linux Kernel Mailing List on Thursday, March 26, 2009 - 12:26 pm. (1 message)

Next thread: platform: make better use of to_platform_{device,driver}() macros by Linux Kernel Mailing List on Thursday, March 26, 2009 - 12:26 pm. (1 message)