linux-stable.git/drivers/base/dd.c, branch linux-2.6.30.y

driver synchronization: make scsi_wait_scan more advanced

2009-04-22T02:40:00+00:00

There is currently only one way for userspace to say "wait for my storage
device to get ready for the modules I just loaded": to load the
scsi_wait_scan module. Expectations of userspace are that once this
module is loaded, all the (storage) devices for which the drivers
were loaded before the module load are present.

Now, there are some issues with the implementation, and the async
stuff got caught in the middle of this: The existing code only
waits for the scsy async probing to finish, but it did not take
into account at all that probing might not have begun yet.
(Russell ran into this problem on his computer and the fix works for him)

This patch fixes this more thoroughly than the previous "fix", which
had some bad side effects (namely, for kernel code that wanted to wait for
the scsi scan it would also do an async sync, which would deadlock if you did
it from async context already.. there's a report about that on lkml):
The patch makes the module first wait for all device driver probes, and then it
will wait for the scsi parallel scan to finish.

Signed-off-by: Arjan van de Ven 
Tested-by: Russell King 
Signed-off-by: Linus Torvalds

driver core: move knode_driver into private structure

2009-03-24T23:38:25+00:00

Nothing outside of the driver core should ever touch knode_driver, so
move it out of the public eye.

Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

driver core: remove polling for driver_probe_done(v5)

2009-03-24T23:38:25+00:00

This patch removes 100ms polling for driver_probe_done in
wait_for_device_probe(), and uses wait_event() instead.
Removing polling in fs initialization may lead to
a faster boot.

This patch also changes the return type of wait_for_device_done()
from int to void.

This patch is against Arjan's patch in linux-next tree.

Signed-off-by: Ming Lei 
Acked-by: Cornelia Huck 
Reviewed-by: Arjan van de Ven 
Signed-off-by: Greg Kroah-Hartman

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

2009-03-24T23:38:24+00:00

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 
Acked-by: Cornelia Huck 
Signed-off-by: Greg Kroah-Hartman

Consolidate driver_probe_done() loops into one place

2009-02-21T22:17:17+00:00

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 
Signed-off-by: Rafael J. Wysocki 
Cc: Len Brown 
Acked-by: Greg KH 
Signed-off-by: Linus Torvalds

Revert "driver core: move knode_driver into private structure"

2009-01-09T22:44:18+00:00

This reverts commit 93e746db183b3bdbbda67900f79b5835f9cb388f.

Turns out that device_initialize shouldn't fail silently.
This series needs to be reworked in order to get into proper
shape.

Reported-by: Stefan Richter 
Cc: Alan Cox 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

driver core:fix duplicate removing driver link in __device_release_driver

2009-01-06T18:44:33+00:00

In __device_release_driver(),driver_sysfs_remove() has removed the
driver link under device dir in sysfs, but sysfs_remove_link() is
called again to do such thing. Remove the duplicate call to
sys_remove_link().

Signed-off-by: Ming Lei 
Signed-off-by: Greg Kroah-Hartman

driver core: move knode_driver into private structure

2009-01-06T18:44:32+00:00

Nothing outside of the driver core should ever touch knode_driver, so
move it out of the public eye.

Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

driver core: struct device - replace bus_id with dev_name(), dev_set_name()

2009-01-06T18:44:31+00:00

Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

device model: Do a quickcheck for driver binding before doing an expensive check

2008-10-16T16:24:50+00:00

This patch adds a quick check for the driver<->device match before
taking the locks and doin gthe expensive checks. Taking the lock hurts
in asynchronous boot context where the device lock gets hit; one of the
init functions takes the lock and goes to do an expensive hardware init;
the other init functions walk the same PCI list and get stuck on the
lock as a result.

For the common case, we can know there's no chance whatsoever of a match
if the device isn't in the drivers ID table... so this patch does that
check as a best-effort-avoid-the-lock approach.

Bootcharts for before and after can be seen at
http://www.fenrus.org/before.svg
http://www.fenrus.org/after.svg

Note the long time "agp_ali_init" takes in the first graph; my laptop
doesn't even have an ALI chip in it!  (the bootgraphs look a bit
dissimilar, but that's the point, the first one has a bunch of arbitrary
delays in it that cause it to look very different)

This reduces my kernel boot time by about 20%

Signed-off-by: Arjan van de Ven 
Cc: Alan Stern 
Signed-off-by: Greg Kroah-Hartman