]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[PATCH] cpufreq: make the transition_notifier chain use SRCU
authorAlan Stern <stern@rowland.harvard.edu>
Wed, 4 Oct 2006 09:17:06 +0000 (02:17 -0700)
committerLinus Torvalds <torvalds@g5.osdl.org>
Wed, 4 Oct 2006 14:55:30 +0000 (07:55 -0700)
commitb4dfdbb3c707474a2254c5b4d7e62be31a4b7da9
tree20558266428cb904c4ffc660647cfdb7e7abeae5
parente6a92013ba458804161c0c5b6d134d82204dc233
[PATCH] cpufreq: make the transition_notifier chain use SRCU

This patch (as762) changes the cpufreq_transition_notifier_list from a
blocking_notifier_head to an srcu_notifier_head.  This will prevent errors
caused attempting to call down_read() to access the notifier chain at a
time when interrupts must remain disabled, during system suspend.

It's not clear to me whether this is really necessary; perhaps the chain
could be made into an atomic_notifier.  However a couple of the callout
routines do use blocking operations, so this approach seems safer.

The head of the notifier chain needs to be initialized before use; this is
done by an __init routine at core_initcall time.  If this turns out not to
be a good choice, it can easily be changed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Jesse Brandeburg <jesse.brandeburg@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/cpufreq/cpufreq.c