[PATCH] RCU: clean up a few remaining synchronize_kernel() calls

2.6.12-rc6-mm1 has a few remaining synchronize_kernel()s, some (but not
all) in comments.  This patch changes these synchronize_kernel() calls (and
comments) to synchronize_rcu() or synchronize_sched() as follows:

- arch/x86_64/kernel/mce.c mce_read(): change to synchronize_sched() to
  handle races with machine-check exceptions (synchronize_rcu() would not cut
  it given RCU implementations intended for hardcore realtime use.

- drivers/input/serio/i8042.c i8042_stop(): change to synchronize_sched() to
  handle races with i8042_interrupt() interrupt handler.  Again,
  synchronize_rcu() would not cut it given RCU implementations intended for
  hardcore realtime use.

- include/*/kdebug.h comments: change to synchronize_sched() to handle races
  with NMIs.  As before, synchronize_rcu() would not cut it...

- include/linux/list.h comment: change to synchronize_rcu(), since this
  comment is for list_del_rcu().

- security/keys/key.c unregister_key_type(): change to synchronize_rcu(),
  since this is interacting with RCU read side.

- security/keys/process_keys.c install_session_keyring(): change to
  synchronize_rcu(), since this is interacting with RCU read side.

Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index 3304d37bb37..fb89f984446 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -980,7 +980,7 @@ void unregister_key_type(struct key_type *ktype)
         spin_unlock(&key_serial_lock);
 
         /* make sure everyone revalidates their keys */
-        synchronize_kernel();
+        synchronize_rcu();
 
         /* we should now be able to destroy the payloads of all the keys of
          * this type with impunity */
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 34db087bbcc..9b0369c5a22 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -234,7 +234,7 @@ static int install_session_keyring(struct task_struct *tsk,
         ret = 0;
 
         /* we're using RCU on the pointer */
-        synchronize_kernel();
+        synchronize_rcu();
         key_put(old);
  error:
         return ret;