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

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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 6cd4958609,
which leads to a faster boot. But the commit 6cd4958609 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>
This commit is contained in:
Ming Lei
2009-01-21 23:27:47 +08:00
committed by Greg Kroah-Hartman
parent 4a67a1bc0b
commit 49b420a13f
3 changed files with 13 additions and 13 deletions
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2
drivers/base/bus.c
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@@ -198,7 +198,7 @@ static ssize_t driver_bind(struct device_driver *drv,
int err = -ENODEV;
dev = bus_find_device_by_name(bus, NULL, buf);
if (dev && dev->driver == NULL) {
if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
if (dev->parent) /* Needed for USB */
down(&dev->parent->sem);
down(&dev->sem);