Add comments requested by Andrew.
Updated comments about synchronize_sched(). Since we use call_rcu and
rcu_barrier now, these comments were out of sync with the code.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Mason <mmlnx@us.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: David Smith <dsmith@redhat.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Adrian Bunk <adrian.bunk@movial.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- * disabling preemption to make sure the teardown of the callbacks can
- * be done correctly when they are in modules and they insure RCU read
- * coherency.
+ * preempt_disable does two things : disabling preemption to make sure
+ * the teardown of the callbacks can be done correctly when they are in
+ * modules and they insure RCU read coherency.
*/
preempt_disable();
ptype = ACCESS_ONCE(mdata->ptype);
*/
preempt_disable();
ptype = ACCESS_ONCE(mdata->ptype);
/*
* Disable a marker and its probe callback.
/*
* Disable a marker and its probe callback.
- * Note: only after a synchronize_sched() issued after setting elem->call to the
- * empty function insures that the original callback is not used anymore. This
- * insured by preemption disabling around the call site.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
*/
static void disable_marker(struct marker *elem)
{
*/
static void disable_marker(struct marker *elem)
{
elem->ptype = 0; /* single probe */
/*
* Leave the private data and id there, because removal is racy and
elem->ptype = 0; /* single probe */
/*
* Leave the private data and id there, because removal is racy and
- * should be done only after a synchronize_sched(). These are never used
- * until the next initialization anyway.
+ * should be done only after an RCU period. These are never used until
+ * the next initialization anyway.
/*
* Update probes, removing the faulty probes.
/*
* Update probes, removing the faulty probes.
- * Issues a synchronize_sched() when no reference to the module passed
- * as parameter is found in the probes so the probe module can be
- * safely unloaded from now on.
*
* Internal callback only changed before the first probe is connected to it.
* Single probe private data can only be changed on 0 -> 1 and 2 -> 1
*
* Internal callback only changed before the first probe is connected to it.
* Single probe private data can only be changed on 0 -> 1 and 2 -> 1